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Sheffield Resources Ltd. — Capital/Financing Update 2015
Jul 30, 2015
44780_rns_2015-07-30_01fa336f-2f2d-4b5b-a0c7-c8f095d09a2d.pdf
Capital/Financing Update
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ASX and Media Release 31 July 2015
THUNDERBIRD HIGH GRADE RESOURCE UPDATE
KEY POINTS
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Infill drilling triples the Measured category of the high grade component of resource to 110 million tonnes (Mt) @ 14.9% heavy mineral (HM)
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Exceptionally high in-situ zircon (1.09%) and ilmenite (4.0%) grades in the Measured category of the high grade component of the resource
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Coherent high grade zone of 1.09Bt @ 11.9% HM (7.5% HM cut-off)
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Confirms Thunderbird as a globally significant zircon deposit
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Provides strong platform for upcoming Pre-Feasibility Study update due Q4 2015, which will incorporate this resource update
Mineral sands company Sheffield Resources (“Sheffield”) (ASX:SFX) today announced an updated mineral resource of 3.240Bt @ 6.9% HM, which includes a coherent high grade zone of 1.09Bt @ 11.9% HM at 7.5% HM cut-off (Measured, Indicated and Inferred), for the Thunderbird heavy mineral sands (HMS) Project near Derby in northwest Western Australia (Figure 7).
Table 1: Thunderbird Deposit Mineral Resource[1] Summary
Mineral Resources |
Valuable HMGrade (In-situ)2 |
|---|---|
| Resource Category Cut-off HM% Material Million Tonnes3 HM % |
Zircon % HiTi Leucoxene % Leucoxene % Ilmenite % |
| Measured 3.0 230 9.4 |
0.74 0.21 0.20 2.5 |
| Indicated 3.0 2,410 6.9 |
0.58 0.19 0.22 1.9 |
| Inferred 3.0 600 5.6 |
0.47 0.16 0.20 1.5 |
| Total 3.0 3,240 6.9 |
0.57 0.18 0.21 1.9 |
| Measured 7.5 110 14.9 |
1.09 0.31 0.28 4.0 |
| Indicated 7.5 850 11.8 |
0.90 0.28 0.25 3.3 |
| Inferred 7.5 130 10.7 |
0.82 0.25 0.23 3.0 |
| Total 7.5 1,090 11.9 |
0.91 0.28 0.25 3.3 |
The high grade zone of 1.09Bt @ 11.9% HM contains 9.9Mt of zircon, 3.0Mt of high-titanium leucoxene, 2.8Mt of leucoxene and 36Mt of ilmenite.
The most significant aspect of the resource update is the increase in the Measured category to 110Mt @ 14.9% HM (at a 7.5% HM cut-off) with very high in-situ zircon and ilmenite grades of 1.09% and 4.0% respectively (Table 1, Figure 1).
1 Data is sourced from Appendix 2, and also presented in Tables 2 & 3 (below). Refer to Appendix 1 for further information. 2 The in-situ grade is determined by multiplying the percentage of HM by the percentage of each valuable heavy mineral within the heavy mineral assemblage at the resource block model scale.
3 Tonnes and grades have been rounded to reflect the relative uncertainty of the estimate, thus the sum of columns may not equal.
Sheffield Resources Ltd ACN 125 811 083 L1, 57 Havelock Street West Perth WA 6005 T: +61(0) 8 6424 8440 F: +61(0) 8 9321 1710
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The majority of the Measured Resource occurs in the shallow up-dip portion of the deposit which is being scheduled for early production years (Figure 2).
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Figure 1: Thunderbird high-grade resource growth (contained VHM at 7.5% HM cut-off)
Managing Director Bruce McQuitty said the resource update is expected to have a positive impact on the Thunderbird project economics.
“This resource update demonstrates that the Thunderbird deposit is superior in size and grade to the vast majority of existing mineral sands operations and projects under investigation globally.
“The updated resource will allow us to undertake detailed mine planning to schedule higher grade feed in early production years. The aim is to increase revenues and to shorten the payback period.
“In addition, the 2015 drill program has recently been completed, with assay results expected Q3 2015 which will be factored into an updated mineral resource targeted for Q4 2015. The recent drilling program was designed to further increase the amount of resource in the Measured category to cover the first 8 to 10 years of scheduled production from this globally significant deposit.
“The Thunderbird PFS update is also progressing well and will be completed during Q4 2015, incorporating this resource update.”
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Figure 2: Thunderbird Resource block model resource category plan, and comparison with December 2014 resource category boundaries and May 2015 PFS pit shells
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Figure 3: Cross-section F-F’ through the Thunderbird resource block model showing the current Resource HM grade and May 2015 PFS pit shell outlines
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Figure 4: Cross-section F-F’ through the Thunderbird resource block model showing the current Resource Zircon grade and May 2015 PFS pit shell outlines
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Figure 5: Cross-section F-F’ through the Thunderbird Resource block model with the current Resource Titanium minerals grade and May 2015 PFS pit shell outlines
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Figure 6: Thunderbird Resource block model >0.9% in-situ zircon left and >3% TiO2 minerals right
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About the Thunderbird Deposit
The Thunderbird deposit is located on the Dampier Peninsula about 60km west of Derby, and 25km north of the sealed Great Northern Hwy joining Derby and Broome (Figure 7).
Thunderbird is the first major mineral sands deposit to be discovered in the Canning Basin, which is rapidly emerging as an important new mineral sands province. Sheffield has a strategic tenement holding in the region of over 5,795km[2] .
The Thunderbird deposit has many attributes that favour large scale mining. Mineralisation occurs as a gently-dipping, thick, broad sheet-like body. A high grade zone (+7.5% HM) averaging 16m thickness is encased within a halo of lower grade (+3% HM)
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Figure 7: Location of the Thunderbird Deposit and Sheffield’s tenement holding in the Canning Basin
mineralisation averaging 38m thickness (Figure 3). In the north-east sector of the deposit, the upper part of the mineralised sequence has been eroded, leaving an extensive zone of high grade mineralisation with minimal overburden. Sheffield is prioritising this area of the deposit for early production years.
The May 2015 PFS, based on the previous Resource, indicated a very low waste-to-ore ratio of 0.22:1 for the first 10 years and 0.68:1 for the life of mine (32 years).
The continuity of high grade mineralisation is exceptionally strong, with high grade zircon (+0.9%) and titanium mineralisation (+3.0%) occurring as coherent bodies (Figures 4 to 6).
The shallower half of the deposit has higher in-situ VHM grades, while the overall mineralised package thickens down-dip (Figures 3 to 5).
Mineral Resource
This updated mineral resource incorporates results from 560 drill holes for a total 33,608.5m drilled by Sheffield between 2012 and 2014, including 51 new infill holes drilled towards the end of 2014 (refer to ASX releases dated 9 February 2015 and 12 December 2014). The resource in this announcement supercedes all previously announced Mineral Resources for Thunderbird.
At 3% HM cut-off the Resource covers an area which is 8.5km long and between 3km and 6.5km wide and remains open in most directions. The mineralisation occurs as a thick, broad sheet-like body striking northwest, extending from surface to a maximum depth of 155m. The average depth to the top of main body of mineralisation is 36m and the average mineralised thickness is 38m (Figures 3-5). The deposit is flat-lying along the north-eastern flank, but the dip steepens to 4 degrees along the south-western flank. Around 30% of the total resource area occurs within 6m of surface.
At 7.5% HM cut-off the Resource covers an area about 7.5km long by 2.5km to 6.5km wide, and remains open to the north and south. This higher grade mineralisation is enclosed within the 3% cut-off Resource envelope, but has a north-south long axis orientation which is oblique to the regional strike. The high grade mineralisation extends from surface to a maximum modelled depth of 126m. The average depth to the top of the high-grade mineralisation is
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35m and the average mineralised thickness is 16m (Figures 3-5). Approximately 26% of the >7.5% resource area is within 15m of surface.
The Resource includes the results of 702 samples which were analysed to determine the HM assemblage, representing 69% of the metres drilled within mineralisation. The analytical method used a combination of screening, magnetic separation, QEMSCAN and XRF. The method was developed following mineralogical trials guided by bulk sample metallurgical test work.
At a 3% HM cut-off, the HM assemblage of the total Resource comprises 8.3% zircon, 2.7% hightitanium leucoxene, 3.1% leucoxene and 28% ilmenite for a total VHM component of 42%. Process test work has shown that these valuable heavy minerals can be recovered using standard mineral sands processing techniques.
Further information relating to the Mineral Resource is included in Appendix 1 and 2 of this announcement.
Geology
The Thunderbird deposit is hosted by deeply weathered Cretaceous-aged formations. Its areal extent, thickness, grainsize, excellent grade and geological continuity are thought to indicate an off-shore, sub-wave base depositional environment.
Sheffield geologists have defined five stratigraphic units within the deposit area using a combination of surface mapping and drill hole lithological logs. These are referred to locally as the Fraser Beds, Reeves, Melligo, Thunderbird and Jowlaenga Formations. Of these, the Thunderbird Formation is the main mineralised unit.
The Thunderbird Formation comprises medium to dark brown/orange, fine to very fine wellsorted loose sands. It is over 90m thick and is very rich in heavy minerals (up to 40% HM). Within the Formation are layers of iron cemented sandstone, interpreted to have been formed by post-depositional chemical processes involving ancient water table movements leaching iron oxides from iron-bearing minerals such as ilmenite. They are a minor component of the overall mineralised sequence and have a patchy distribution, they are typically 5-10cm thick and cannot be traced between adjacent drill holes (closest drill spacing is currently about 60m).
Within the Thunderbird Formation is a continuous zone of very high grade HM (>7.5%) named the “GT Zone”. The GT Zone is up to 43m thick (average 15m) over an area about 7.5km x 4km, strikes approximately north-south, follows the dip of the Thunderbird Formation and is open along strike. The GT Zone is interpreted to have formed in off-shore higher wave energy shoals.
ENDS
For further information please contact:
Bruce McQuitty Managing Director Tel: 08 6424 8440 [email protected]
Media: Luke Forrestal/Annette Ellis Cannings Purple Tel: 08 6314 6300 [email protected]
Website: www.sheffieldresources.com.au
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Table 2: Thunderbird Deposit Mineral Resource[1]
| Mineral | Resources | Resources | Mineral Assemblage2 | Mineral Assemblage2 | Mineral Assemblage2 | Mineral Assemblage2 | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Resource Category |
Cut off (HM%) |
Material (Mt) |
Bulk Density |
HM % |
Slime s % |
Osize % |
In-situ HM (Mt) |
Zircon % |
HiTi Leuc % |
Leuc % |
Ilmenite % |
| Measured | 3.0 |
230 | 2.1 | 9.4 | 19 | 10 | 21 | 7.9 | 2.2 | 2.1 | 27 |
| Indicated | 3.0 | 2,410 | 2.0 | 6.9 | 16 | 8 | 167 | 8.4 | 2.7 | 3.1 | 28 |
| Inferred | 3.0 | 600 | 2.0 | 5.6 | 16 | 9 | 33 | 8.4 | 2.8 | 3.5 | 28 |
| Total | 3.0 | 3,240 | 2.1 | 6.9 | 16 | 9 | 222 | 8.3 | 2.7 | 3.1 | 28 |
| Measured | 7.5 |
110 | 2.2 | 14.9 | 17 | 13 | 16 | 7.3 | 2.1 | 1.9 | 27 |
| Indicated | 7.5 | 850 | 2.1 | 11.8 | 15 | 10 | 100 | 7.6 | 2.4 | 2.2 | 28 |
| Inferred | 7.5 | 130 | 2.0 | 10.7 | 14 | 9 | 14 | 7.6 | 2.3 | 2.2 | 28 |
| Total | 7.5 | 1,090 | 2.1 | 11.9 | 15 | 10 | 131 | 7.6 | 2.3 | 2.1 | 28 |
Table 3: Thunderbird Deposit contained Valuable HM (VHM) Resource Inventory[1]
| Resource | Cut off | Zircon |
HiTi Leucoxene | Leucoxene | Ilmenite | Total VHM |
|---|---|---|---|---|---|---|
| Category | (HM%) | (kt) |
(kt) | (kt) | (kt) | (kt) |
| Measured | 3.0 | 1,700 | 500 | 500 | 5,800 | 8,400 |
| Indicated | 3.0 | 14,000 | 4,500 | 5,300 | 46,700 | 70,500 |
| Inferred | 3.0 | 2,800 | 900 | 1,200 | 9,300 | 14,200 |
| Total | 3.0 | 18,500 | 5,900 | 6,900 | 61,800 | 93,100 |
| Measured | 7.5 | 1,200 | 300 | 300 | 4,300 | 6,100 |
| Indicated | 7.5 | 7,700 | 2,400 | 2,200 | 27,800 | 40,000 |
| Inferred | 7.5 | 1,100 | 300 | 300 | 3,900 | 5,700 |
| Total | 7.5 | 9,900 | 3,000 | 2,800 | 36,000 | 51,700 |
1 All tonnages and grades have been rounded to reflect the relative uncertainty of the estimate, thus sum of columns may not equal.[2] Estimates of Mineral Assemblage are presented as percentages of the Heavy Mineral (HM) component of the deposit, as determined by magnetic separation, QEMSCAN and XRF. Magnetic fractions were analysed by QEMSCAN for mineral determination as follows: Ilmenite: 40-70% TiO2 >90% Liberation; Leucoxene: 70-94% TiO2 >90% Liberation; High Titanium Leucoxene (HiTi Leucoxene): >94% TiO2 >90% Liberation; and Zircon: 66.7% ZrO2+HfO2 >90% Liberation. The nonmagnetic fraction was submitted for XRF analysis and minerals determined as follows: Zircon: ZrO2+HfO2/0.667 and High Titanium Leucoxene (HiTi Leucoxene): TiO2/0.94.
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Figure 8: Thunderbird resource grade-tonnage curve.
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COMPLIANCE STATEMENTS
MINERAL RESOURCES
The information in this report that relates to Mineral Resources is based on information compiled under the guidance of Mr Mark Teakle, a Competent Person who is a Member of the Australasian Institute of Geoscientists (AIG) and the Australasian Institute of Mining and Metallurgy (AusIMM). Mr Teakle is a full-time employee of Sheffield Resources Ltd and has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken to qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Mr Teakle consents to the inclusion in the report of the matters based on his information in the form and context in which it appears.
The information in this report that relates to the estimation of Mineral Resources is based on information compiled by Mr Trent Strickland, who is a Member of the Australasian Institute of Mining and Metallurgy (AusIMM). Mr Strickland is a full time employee of QG Australia Pty Ltd and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Mr Strickland consents to the inclusion in this report of the matters based on his information in the form and context in which it appears.
PREVIOUSLY REPORTED INFORMATION
This report includes information that relates to Exploration Results, Mineral Resources and Technical Studies which were prepared and first disclosed under the JORC Code 2012. The information was extracted from the Company’s previous ASX announcements as follows:
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Thunderbird PFS Update progress: “QUARTERLY REPORT FOR PERIOD ENDING 30 JUNE 2015” 27 July 2015
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Thunderbird pre-feasibility study: “PRE-FEASIBILITY STUDY CONFIRMS THUNDERBIRD AS NEXT MAJOR MINERAL SANDS PROJECT IN GLOBAL DEVELOPMENT PIPELINE” 14 May 2015
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Thunderbird infill drilling results: “EXCEPTIONALLY HIGH GRADES FROM INFILL DRILLING AT THUNDERBIRD MINERAL SANDS PROJECT” 9 February, 2015
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Thunderbird Resource Update: “THUNDERBIRD HIGH GRADE RESOURCE SURPASSES ONE BILLION TONNES” 12 December 2014
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Thunderbird Scoping Study: “SCOPING STUDY HIGHLIGHTS THUNDERBIRD’S EXCEPTIONAL FINANCIAL RETURNS” 14 April, 2014
These announcements are available on Sheffield Resources Ltd’s web site www.sheffieldresources.com.au.
The Company confirms that it is not aware of any new information or data that materially affects the information included in the original market announcements and, in the case of estimates of Mineral Resources, Scoping and Pre-Feasibility studies, that all material assumptions and technical parameters underpinning the estimates in the relevant market announcement continue to apply and have not materially changed. The Company confirms that the form and context in which the Competent Person’s findings are presented have not been materially modified from the original market announcement.
FORWARD LOOKING STATEMENTS
Some statements in this report regarding estimates or future events are forward-looking statements. They involve risk and uncertainties that could cause actual results to differ from estimated results. Forward-looking statements include, but are not limited to, statements concerning the Company’s exploration programme, outlook, target sizes and mineralised material estimates. They include statements preceded by words such as “anticipated”, “expected”, “likely” “should”, “scheduled”, “intends”, “potential”, “prospective” and similar expressions.
In this report the term “mining inventory” is used to report that part of the Mineral Resource that has been considered in the Pre-feasibility Study. The mining inventory does not meet the requirements of an Ore Reserve as defined under the 2012 edition of the JORC Code and should not be considered an Ore Reserve. There is no certainty that all or any part of the mining inventory will be converted into Ore Reserves.
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ABOUT SHEFFIELD RESOURCES
Sheffield Resources Limited ( Sheffield ) is a rapidly emerging heavy mineral sands (HMS) company.
| ASX Code – SFX | Market Cap @ 48cps - $64.5m |
|---|---|
| Issued shares – 134.4m | Cash - $5.1m (at 30 June 2015) |
Sheffield’s projects are all situated within the state of Western Australia and are 100% owned by the Company.
HEAVY MINERAL SANDS
The Dampier project, located near Derby in WA’s northwest, contains the large, high grade zircon-rich Thunderbird HMS deposit. Sheffield’s pre-feasibility study shows Thunderbird can generate strong cash margins from globally significant levels of production over a 32 year mine life.
The Eneabba project comprises multiple HMS deposits and is located near Eneabba approximately 140km south of the port of Geraldton in WA’s Mid-West region.
Sheffield is also evaluating the large McCalls chloride ilmenite project, located 110km to the north of Perth.
NICKEL-COPPER
Sheffield has over 2,000km[2] of tenure in the Fraser Range region, including the Red Bull project which is within 20km of Sirius Resources NL’s (ASX:SIR) Nova Ni-Cu deposit.
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Glossary
Heavy Mineral (“HM”) Material (individual minerals or mineral aggregates) which does not pass through a screen (mesh) of nominated size (the “Slimes” screen, eg. 38µm) and does pass through a screen of nominated size (the “Oversize” screen, eg. 1mm) and has density greater than a nominated amount (typically 2.85 to 2.96g/ml). HM% Weight percentage of Heavy Mineral in a sample. Oversize (“OS” or “Osize”) Material that does not pass through a screen of nominated size, for Thunderbird this is universally 1mm. OS% Weight percentage of Oversize material in a sample. Slimes (“SL”) Material that passes through a screen of nominated size, for Thunderbird 38µm and 45µm screens were used. SL% Weight percentage of Slimes material in a sample. Valuable Heavy Mineral (“VHM” or “Valuable HM”) Component of Heavy Mineral which has the potential to become marketable products; eg. zircon, ilmenite, rutile, leucoxene, HiTi Leucoxene, etc.
Appendix 1: JORC (2012) Table 1 Report
Section 1 Sampling Techniques and Data
(Criteria in this section apply to all succeeding sections.)
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| Sampling | | Nature and quality of sampling (eg cut | | NQ and HQ diameter aircore drilling used to |
| techniques | channels, random chips, or specific | collect 2-3kg samples at 1.5m intervals down- | ||
| specialised industry standard | hole. | |||
| measurement tools appropriate to the | | Mineral sands industry-standard drilling | ||
| minerals under investigation, such as | technique. | |||
| down hole gamma sondes, or | | See below for sample and assay QAQC | ||
| handheld XRF instruments, etc). These | procedures and analysis. | |||
| examples should not be taken as | ||||
| limiting the broad meaning of | ||||
| sampling. | ||||
| | Include reference to measures taken to | |||
| ensure sample representivity and the | ||||
| appropriate calibration of any | ||||
| measurement tools or systems used. | ||||
| | Aspects of the determination of | |||
| mineralisation that are Material to the | ||||
| Public Report. | ||||
| | In cases where ‘industry standard’ work | |||
| has been done this would be relatively | ||||
| simple (eg ‘reverse circulation drilling | ||||
| was used to obtain 1 m samples from | ||||
| which 3 kg was pulverised to produce | ||||
| a 30 g charge for fire assay’). In other | ||||
| cases more explanation may be | ||||
| required, such as where there is coarse | ||||
| gold that has inherent sampling | ||||
| problems. Unusual commodities or | ||||
| mineralisation types (eg submarine | ||||
| nodules) may warrant disclosure of | ||||
| detailed information. | ||||
| Drilling | | Drill type (eg core, reverse circulation, | | Aircore system; NQ size for 39% of drill |
| techniques | open-hole hammer, rotary air blast, | database (13,148m); HQ diameter for 57% | ||
| auger, Bangka, sonic, etc) and details | (19,324m), 75mm diameter aircore 3% of drill | |||
| (eg core diameter, triple or standard | database (1,137m). | |||
| tube, depth of diamond tails, face- | | Blade drill bit used for majority (88%) of drilling. | ||
| sampling bit or other type, whether | | Where hard rock layers were intersected and | ||
| core is oriented and if so, by what | unable to drill with blade bit,apencil(open- |
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| Criteria JORC Code explanation |
Commentary |
|---|---|
| method, etc). | hole) or reverse circulation hammer was used to penetrate the layer. System used as an industry standard for HMS deposits. |
| Drill sample recovery Method of recording and assessing core and chip sample recoveries and results assessed. Measures taken to maximise sample recovery and ensure representative nature of the samples. Whether a relationship exists between sample recovery and grade and whether sample bias may have occurred due to preferential loss/gain of fine/coarse material. |
An orientation process was undertaken at the beginning of the program to optimise the sampling system to collect a 2-3kg sub- sample from 1.5m intervals. The remainder of the drill sample (spoil) has been retained as 3m-composites for future analysis if required. Sample weight is recorded at the laboratory Duplicate samples are collected at the drill site (see below) to enable analysis of data precision. Sample condition (wet to dry and good to poor qualitative recovery) is logged at the drill site. Of the total database, 35% were collected as wet samples and 4% were classed as having poor recovery. There is a small negative bias in HM% and OS% and a small positive bias in SL% for dry compared with wet samples. There is a small negative bias in HM% and OS% and a positive bias in SL% for samples with good recovery compared to those with poor recovery. Recovery has a greater influence than wetness on HM%, OS% and SL% values. The very small number of wet-poor recovery samples in the database (2%), and the conservative bias in HM grade suggests no significant effect on the resource estimate due to sample condition. The sample quality is considered appropriate for the Mineral Resource estimation procedure and classification applied. |
| Logging Whether core and chip samples have been geologically and geotechnically logged to a level of detail to support appropriate Mineral Resource estimation, mining studies and metallurgical studies. Whether logging is qualitative or quantitative in nature. Core (or costean, channel, etc) photography. The total length and percentage of the relevant intersections logged. |
Every drill sample is washed and panned, then geologically logged on-site in 1.5m intervals, recording primary, secondary and oversize lithology, qualitative hardness, grainsize, rounding, sorting, and washability, visual estimates of HM%, SL% and OS%, and depth to water table. The entire length of the drill hole is logged; minimum (nominal) interval length is 1.5m. Logging is suitable such that interpretations of grade and deposit geology can be used to support the Mineral Resource estimation procedure and classification applied. Recent Pre-feasibility work at Thunderbird included 20 sonic core holes drilled as part of geotechnical investigations. The results of this program are not incorporated into this resource estimate, however visual observations have been incorporated into the geological interpretation of the deposit (see below) |
| Sub-sampling techniques and sample preparation If core, whether cut or sawn and whether quarter, half or all core taken. If non-core, whether riffled, tube sampled, rotary split, etc and whether |
HM%, SL% OS% Determination Drill Site A 2-3kg sample is collected at 1.5m intervals in numbered bags at the drill site via rotary |
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| Criteria JORC Code explanation |
Commentary |
|---|---|
| sampled wet or dry. For all sample types, the nature, quality and appropriateness of the sample preparation technique. Quality control procedures adopted for all sub-sampling stages to maximise representivity of samples. Measures taken to ensure that the sampling is representative of the in situ material collected, including for instance results for field duplicate/second-half sampling. Whether sample sizes are appropriate to the grain size of the material being sampled. |
splitter at the cyclone discharge point. Duplicate samples (field duplicates) collected at drill site 1 in every 40 samples. Reference standard and blank material samples inserted 1 each in every 40 samples. Samples submitted to an external laboratory for heavy liquid separation (HLS) determination of weight per cent heavy mineral (HM%), Slimes (SL%) and Oversize (OS%). Laboratory The 2-3kg drill sample is sub-sampled via a rotary splitter to approx. 200g for analysis. The 200g sub-sample is soaked overnight in water. 2012 samples: (23% of sample database) then screened and weighed. 2013 & 2014 samples: (77% of sample database) a 5 minute attrition in a plastic bucket with low solids density, then screened and weighed. HM%, SL% and OS% calculated as percentage of total sample weight (see below). Laboratory repeats are conducted 1 in every 20 samples (97% of the assay database) or 1 in every 15 samples (3% of the assay database). Laboratory internal standard inserted 1 in every 40 samples (97% of the assay database). Laboratory provides a sachet containing the Heavy Mineral Concentrate (HMC) for each sample – this is used in HM assemblage determination (see below). All Spacing of duplicate, standard, blank and lab repeat samples are designed to identify sample misplacement or misallocation during sample collection and laboratory analysis. Visual estimates of HM%, SL% and OS% logged at the drill site are compared against laboratory results to identify significant errors. Analysis of field duplicate samples and laboratory repeats show the data has acceptable precision, indicating the sub- sampling and sample preparation techniques are appropriate for the deposit style and the Mineral Resource estimation procedure and classification applied. HM Assemblage Determination Heavy Mineral Concentrate (HMC) from individual samples is combined according to HM grade and weight into (nominal) 50g – 100g composite samples for HM assemblage determination. Weighed HMC is split via a micro-riffle to ensure HM%, SL% and OS% of the final composite sample can be correctly calculated. HM assemblage determination was bya |
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| Criteria JORC Code explanation |
Commentary |
|---|---|
| combination of screening, magnetic separation, QEMSCAN™ and XRF assay to determine the component mineralogy. This is considered an industry standard method, typically optimised according to the HM characteristics of individual deposits. For Thunderbird the method was designed and optimised using an iterative trial process and the results of 6t and 5t bulk sample process metallurgical testwork. 3% of samples in the HM assemblage database were repeated from the original drill sample and 4% of samples were repeated from the composite HMC. Analysis of these repeats show the data has acceptable precision, indicating the sub- sampling and sample preparation techniques are appropriate for the deposit style and the Mineral Resource estimation procedure and classification applied. |
|
| Quality of assay data and laboratory tests The nature, quality and appropriateness of the assaying and laboratory procedures used and whether the technique is considered partial or total. For geophysical tools, spectrometers, handheld XRF instruments, etc, the parameters used in determining the analysis including instrument make and model, reading times, calibrations factors applied and their derivation, etc. Nature of quality control procedures adopted (eg standards, blanks, duplicates, external laboratory checks) and whether acceptable levels of accuracy (ie lack of bias) and precision have been established. |
HM%, SL% OS% Determination Assay and laboratory procedures are industry standard, although method specifics and heavy liquid composition can vary. SL% was determined using a 45µm (30% of samples) or 38µm (70% of samples) screen. OS% was determined using a +1mm screen. HM% was determined using heavy liquid TBE (2.96g/ml). The method produces a total grade as weight per cent of the primary sample. Method does not determine the relative amounts of valuable (saleable or marketable) and non-valuable heavy mineral species. See below for details of HM assemblage determination. Reference standard and blank material samples inserted at the drill site 1 each in every 40 samples. Laboratory internal standard inserted 1 in every 40 samples (97% of the assay database). The HM reference samples used are field- homogenised bulk samples with expected values and ranges determined by the Company from assay results. Blank material used is commercially available builder’s sand. Reference standards and blanks are examined for performance over time and within laboratory batches. Batches or sub- batches are re-analysed if unacceptable QAQC data are returned. In total QAQC samples represent 15% of the total assay database. Analysis of reference standards, blanks and laboratory repeats show the data to be of acceptable accuracy and precision for the Mineral Resource estimation procedure and classification applied. HM Assemblage Determination |
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| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| | HM assemblage determination was by a | |||
| combination of screening, magnetic | ||||
| separation, QEMSCAN™ and XRF assay to | ||||
| determine the component mineralogy of the | ||||
| HMC. | ||||
| | This method is considered an industry | |||
| standard, typically optimised according to | ||||
| the HM characteristics of individual deposits. | ||||
| | For Thunderbird the method was designed | |||
| and optimised using an iterative trial process | ||||
| and the results of 6t and 5t bulk sample | ||||
| process metallurgical testwork. | ||||
| | HMC was screened at 106µm and each | |||
| fraction weighed (studies show Thunderbird | ||||
| HM with grainsize >106µm does not contain | ||||
| significant amounts of VHM). The -106µm | ||||
| fraction was then magnetically separated | ||||
| into highly-susceptible (H/S), magnetic 1, | ||||
| magnetic 2 and non-magnetic fractions, with | ||||
| each fraction weighed. The magnetic 1 & 2 | ||||
| fractions were combined and analysed by | ||||
| QEMSCAN™ for mineral determination as | ||||
| follows: | ||||
| - Ilmenite: 40-70% TiO2>90% Liberation | ||||
| - Leucoxene: 70-94% TiO2>90% Liberation | ||||
| - High Titanium Leucoxene (HiTi | ||||
| Leucoxene): >94% TiO2>90% Liberation | ||||
| - Zircon: 66.7% ZrO2+HfO2>90% Liberation | ||||
| The non-magnetic fraction was submitted for | ||||
| XRF analysis and minerals determined as | ||||
| follows: | ||||
| - Zircon: ZrO2+HfO2/0.667 | ||||
| - High Titanium Leucoxene (HiTi | ||||
| Leucoxene): TiO2/0.94 | ||||
| | Reference material was not used, other | |||
| measures of accuracy and the method | ||||
| design is considered sufficient to establish | ||||
| acceptable accuracy of the data for the | ||||
| Mineral Resource estimation procedure and | ||||
| classification applied. | ||||
| | Analysis of laboratory repeats and | |||
| comparison with bulk metallurgical testwork | ||||
| results show the data to be of acceptable | ||||
| accuracy and precision for the Mineral | ||||
| Resource estimation procedure and | ||||
| classification applied. | ||||
| Verification | | The verification of significant | | Data is logged electronically using “validation |
| of sampling | intersections by either independent or | at point of entry” systems prior to storage in | ||
| and assaying | alternative company personnel. | the Company’s drill hole database, which is | ||
| | The use of twinned holes. | managed by Company personnel and an | ||
| | Documentation of primary data, data | external consultancy. | ||
| entry procedures, data verification, | | Documentation related to data custody and | ||
| data storage (physical and electronic) | validation is maintained by the Company. | |||
| protocols. | | A copy (“snapshot”) of the Mineral Resource | ||
| | Discuss any adjustment to assay data. | database is retained separately from the | ||
| primary drill hole database. | ||||
| | No assay data have been adjusted. | |||
| | 101 twinned drillholes have been examined | |||
| for comparison of assay data between | ||||
| factors such as year drilled, hole diameter, drill | ||||
| type and assaymethod. |
- 15 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| | Analysis of drill hole twins show the 2012 assay | |||
| data (45µm screen and no attritioning step) is | ||||
| biased low in HM% compared with 2013 assay | ||||
| data (45µm screen or 38µm screen, with | ||||
| attritioning step). A similar high bias is seen in | ||||
| OS%. The bias is explained by the low energy | ||||
| attritioning step liberating HM from loosely- | ||||
| held aggregates, and the change in slimes | ||||
| screen from 45 µm to 38 µm used in 2013 and | ||||
| 2014. All data was used for the current | ||||
| Resource estimate, this is considered | ||||
| appropriate because the 2012 data | ||||
| introduces a conservative bias. As a | ||||
| consequence HM grade remains | ||||
| underestimated for 2012 holes rather than | ||||
| overestimated. The 2013 & 2014 dataset is | ||||
| dominant in terms of number of samples, and | ||||
| are distributed throughout the Resource area, | ||||
| therefore any spatial bias is considered | ||||
| insignificant. | ||||
| | 43 twinned drillholes have been examined for | |||
| comparison of HM assemblage data | ||||
| between factors such as determination | ||||
| method, year drilled, and HM assay method. | ||||
| | Analysis shows HM assemblage determined | |||
| by QEMSCAN™ alone on 2012 samples (90 | ||||
| data), and by combination magnetic | ||||
| separation/ QEMSCAN™/XRF on 2012 samples | ||||
| (106 data), has a significant bias low | ||||
| compared with combination magnetic | ||||
| separation/ QEMSCAN™/XRF on 2013 and | ||||
| 2014 samples (702 data). This bias cannot be | ||||
| explained by natural (ie. deposit-related) | ||||
| factors, and is a result of a change in sample | ||||
| preparation from 2012 to 2013 (as discussed | ||||
| above). As a result of this analysis, HM | ||||
| assemblage data used in the Resource | ||||
| estimate includes only samples from holes | ||||
| drilled in 2013 and 2014 (87% of the database) | ||||
| in order to ensure a consistent determination | ||||
| method across the deposit. The mineralogical | ||||
| data was also supplemented with the | ||||
| average mineralogy of a 6t bulk sample, | ||||
| sourced from the 2012 ‘cross’ of 60m spaced | ||||
| drilling. | ||||
| | The verification and treatment of the data is | |||
| considered sufficient for the Mineral Resource | ||||
| estimation procedure and classification | ||||
| applied. | ||||
| Location of | | Accuracy and quality of surveys used | | Drill hole collar locations were surveyed by |
| data points | to locate drill holes (collar and down- | licenced surveyors using a RTK GPS system | ||
| hole surveys), trenches, mine workings | with expected accuracy of +/- 0.02m | |||
| and other locations used in Mineral | horizontal and +/- 0.03m vertical. | |||
| Resource estimation. | | 12 drill holes of the 560 (2%) in the estimate | ||
| | Specification of the grid system used. | database were not surveyed, for these holes | ||
| | Quality and adequacy of topographic | planned or approximated coordinates have | ||
| control. | been used. | |||
| | Coordinates are referenced to the Map Grid | |||
| of Australia (MGA) zone 51 on the | ||||
| Geographic Datum of Australia (GDA94). | ||||
| | Vertical datumgeoid model is AUSGEOID09 |
- 16 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| (Australia). | ||||
| | Drill hole RL for Resource estimation is | |||
| determined by projection of surveyed hole | ||||
| collars to a regional (Landgate) DTM model. | ||||
| | The Mineral Resource estimate uses this model | |||
| as surface topography. The average | ||||
| difference between surveyed and modelled | ||||
| RL is 0.5m which is considered negligible given | ||||
| the nature of the mineralisation, and the size | ||||
| of the Thunderbird deposit. | ||||
| | The quality and accuracy of the topographic | |||
| control is considered sufficient for the Mineral | ||||
| Resource estimation procedure and | ||||
| classification applied. | ||||
| Data spacing | |
Data spacing for reporting of | | See figures in body of announcement for hole |
| and | Exploration Results. | distribution. | ||
| distribution | | Whether the data spacing and | | The nominal spacing of most drill holes is 250m |
| distribution is sufficient to establish the | x 500m, with edges at 500m x 500m and | |||
| degree of geological and grade | 1000m x 500m. Infill drilling has reduced the | |||
| continuity appropriate for the Mineral | nominal spacing to 125m x 250m in the up-dip | |||
| Resource and Ore Reserve estimation | area of the resource. Four areas are drilled at | |||
| procedure(s) and classifications | nominal 60m hole spacing for bulk sample | |||
| applied. | collection and geostatistical data analysis. | |||
| | Whether sample compositing has been | |
The drill database used in the Resource | |
| applied. | estimate comprises 560 holes, totalling | |||
| 33,608.5m, with 22,378 samples assayed | ||||
| totalling 33,453.4m (99.5% of metres drilled). | ||||
| Of that, 13,030 assayed samples totalling | ||||
| 19,460.4m (58%) are within the mineralised | ||||
| zones of the Resource (see below for criteria). | ||||
| | Samples for HM assemblage determination | |||
| are composited on intervals according to a | ||||
| combination of grade and geology | ||||
| appropriate to reflect resource estimation | ||||
| domains. | ||||
| | 702 composites from 331 holes totalling | |||
| 13,454m are used in the resource estimate. | ||||
| This represents 69% of the total length of | ||||
| drillholes within mineralised zones of the | ||||
| resource. | ||||
| | The data spacing and distribution is sufficient | |||
| to establish the degree of geological and | ||||
| grade continuity appropriate for the Mineral | ||||
| Resource estimation procedure and | ||||
| classification applied. | ||||
| Orientation | | Whether the orientation of sampling | | Mineralisation is flat-lying to less than 4deg. |
| of data in | achieves unbiased sampling of possible | dip, vertical drill holes therefore approximate | ||
| relation to | structures and the extent to which this is | true thickness and perpendicular intersection | ||
| geological | known, considering the deposit type. | of mineralisation. | ||
| structure | | If the relationship between the drilling | | Note sections in the body of the |
| orientation and the orientation of key | announcement are displayed with vertical | |||
| mineralised structures is considered to | exaggeration. | |||
| have introduced a sampling bias, this | ||||
| should be assessed and reported if | ||||
| material. | ||||
| Sample | | The measures taken to ensure sample | | Sample security is not considered a significant |
| security | security. | risk given the location of the deposit and bulk- | ||
| nature of mineralisation. | ||||
| | Nevertheless, the use of recognised transport | |||
| providers, sample dispatch procedures | ||||
| directlyfrom the field to the laboratory,and |
- 17 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| the large number of samples are considered | ||||
| sufficient to ensure appropriate sample | ||||
| security. | ||||
| Audits or | | The results of any audits or reviews of | | All data has been validated and reviewed by |
| reviews | sampling techniques and data. | at least 2 Company geologists, and by | ||
| consultants QG Australia. | ||||
| | No external audit or review of sample | |||
| techniques or data, apart from that by QG | ||||
| Australia, has been conducted. | ||||
| | External audits are not considered necessary | |||
| at this stage of the Project’s development. |
Section 2 Reporting of Exploration Results
(Criteria listed in the preceding section also apply to this section.)
| Criteria | Statement | Statement | Commentary | Commentary | |
|---|---|---|---|---|---|
| Mineral | | Type, reference name/number, | | The Mineral Resource reported is entirely | |
| tenement | location and ownership including | within Exploration Licence E04/2083, located | |||
| and land | agreements or material issues with third | on the Dampier Peninsula about 60km west of | |||
| tenure status | parties such as joint ventures, | Derby, and 25km north of the sealed Great | |||
| partnerships, overriding royalties, native | Northern Hwy joining Derby and Broome | ||||
| title interests, historical sites, wilderness | | E04/2083 was granted on 05/09/2011 and is | |||
| or national park and environmental | due to expire on 04/09/2016; it is held 100% by | ||||
| settings. | Sheffield Resources Ltd. On 16/07/2014 | ||||
| | The security of the tenure held at the | Sheffield lodged a Mining Lease Application | |||
| time of reporting along with any known | (M04/459) over the Thunderbird deposit. | ||||
| impediments to obtaining a licence to | | There are no known or experienced | |||
| operate in the area. | impediments to obtaining a licence to | ||||
| operate in the area. | |||||
| | Sheffield has been operating successfully in | ||||
| the region for more than 3years to date. | |||||
| Exploration | | Acknowledgment and appraisal of | | The Dampier project area was explored by | |
| done by | exploration by other parties. | Rio Tinto (“Rio”) between 2003 and 2009. Rio | |||
| other parties | completed four broadly spaced aircore drill | ||||
| traverses, identifying heavy mineral | |||||
| concentrations at Thunderbird averaging | |||||
| 8.07% HM with 8.0% zircon. Rio surrendered | |||||
| the tenements following the 2008 global | |||||
| financial crisis. | |||||
| | Further details are included in Sheffield’s ASX | ||||
| release entitled ‘New Licence Granted Over | |||||
| High Grade Zircon Project’ dated 7 | |||||
| September, 2011 (available from the | |||||
| company’s website: | |||||
| www.sheffieldresources.com.au). | |||||
| Geology | | Deposit type, geological setting and | | The Dampier Project is within the Canning | |
| style of mineralisation. | Basin in the Kimberley region of Western | ||||
| Australia. The Canning Basin is an | |||||
| intracratonic basin which contains Ordovician | |||||
| to Cretaceous deposits covered by Cenozoic | |||||
| sediments. | |||||
| | Thunderbird is a heavy mineral sand (HMS) | ||||
| deposit hosted by deeply weathered | |||||
| Cretaceous-aged formations. Valuable heavy | |||||
| minerals (VHM) contained within the deposit | |||||
| include ilmenite, zircon, leucoxene and rutile. | |||||
| The mineralisation is in a thick, broad anticlinal | |||||
| sheet-like body striking northwest. In the core | |||||
| of the anticline it is at surface, rolling at about | |||||
| 4deg. dipabout the axis,extendingunder |
- 18 -
| Criteria | Statement | Statement | Commentary | Commentary |
|---|---|---|---|---|
| cover to the southwest. The areal extent, | ||||
| width, grade, geological continuity and | ||||
| grainsize of the Thunderbird mineralisation are | ||||
| interpreted to indicate an off-shore, sub-wave | ||||
| base depositional environment. | ||||
| | Five stratigraphic units have been defined by | |||
| Sheffield geologists within the deposit area | ||||
| using a combination of surface mapping and | ||||
| drill hole lithological logs. These are referred to | ||||
| locally as the Fraser Beds, Reeves, Melligo, | ||||
| Thunderbird and Jowlaenga Formations. Of | ||||
| these the Thunderbird Formation is the most | ||||
| important, with the Thunderbird Formation | ||||
| representing the main mineralised unit. Also | ||||
| important, the Fraser Beds act as a distinct | ||||
| marker unit toward the base of the | ||||
| Thunderbird Formation, enabling confidence | ||||
| in interpretation of the extent, strike and dip of | ||||
| the stratigraphy. | ||||
| | The Thunderbird Formation is described as | |||
| medium to dark brown/orange, fine to very | ||||
| fine well sorted loose sands. It is up to 90m | ||||
| thick (average 46m) and is very rich in heavy | ||||
| minerals (up to 40% HM). It is modelled over | ||||
| the Resource area as at least 8.5km along | ||||
| strike and more than 3km to 6.5km wide. | ||||
| | Within the Formation are layers of iron | |||
| cemented sandstone. These layers are | ||||
| interpreted to have been formed by post- | ||||
| depositional chemical processes of | ||||
| ferruginisation from ancient water table | ||||
| movements with iron oxides leached from the | ||||
| sand (eg. ilmenite). They occur throughout | ||||
| but are patchy. Pre-feasibility work at | ||||
| Thunderbird included 20 sonic core holes | ||||
| drilled as part of geotechnical investigations. | ||||
| Whilst the results of this program are not | ||||
| incorporated into this resource estimate, | ||||
| visual observations have confirmed | ||||
| observations of hard rock bands within the | ||||
| deposit to be narrow (typically 5-10cm thick | ||||
| and rarely >30cm thick) and not extensive | ||||
| (not extending as a single layer further than | ||||
| <60m). | ||||
| | Also within the Formation is a continuous, | |||
| very-high grade HM (>7.5%) zone named the | ||||
| GT Zone. This Zone is up to 43m thick (average | ||||
| 16m) over an area at least 7.5km x 4km, strikes | ||||
| approximately north-south, follows the dip of | ||||
| the Thunderbird Formation and is open along | ||||
| strike. The high-grade of HM in the GT zone is | ||||
| interpreted to result from deposition in off- | ||||
| shore higher wave energyshoals. | ||||
| Drill hole | | A summary of all information material | | Exploration results relating to the drillholes |
| Information | to the understanding of the exploration | used in the resource have been publicly | ||
| results including a tabulation of the | released in numerous previous Company | |||
| following information for all Material drill | announcements referring to the Dampier | |||
| holes: | Project and Thunderbird deposit. | |||
o easting and northing of the drill hole |
|
Information relating to the number of | ||
| collar | drillholes, assayed samples, location | |||
o elevation or RL(Reduced Level – |
accuracy,orientation etc. is included in this |
- 19 -
| Criteria | Statement | Statement | Commentary | Commentary |
|---|---|---|---|---|
| elevation above sea level in metres) | table, and in the body of the announcement. | |||
| of the drill hole collar | | Diagrams in the body of the announcement | ||
o dip and azimuth of the hole |
show the location of and distribution of | |||
o down hole length and interception |
drillholes in relation to the Mineral Resource. | |||
| depth | ||||
o hole length. |
||||
| | If the exclusion of this information is | |||
| justified on the basis that the | ||||
| information is not Material and this | ||||
| exclusion does not detract from the | ||||
| understanding of the report, the | ||||
| Competent Person should clearly | ||||
| explain why this is the case. | ||||
| Data | | In reporting Exploration Results, | | N/A |
| aggregation | weighting averaging techniques, | |||
| methods | maximum and/or minimum grade | |||
| truncations (eg cutting of high grades) | ||||
| and cut-off grades are usually Material | ||||
| and should be stated. | ||||
| | Where aggregate intercepts | |||
| incorporate short lengths of high grade | ||||
| results and longer lengths of low grade | ||||
| results, the procedure used for such | ||||
| aggregation should be stated and | ||||
| some typical examples of such | ||||
| aggregations should be shown in | ||||
| detail. | ||||
| | The assumptions used for any reporting | |||
| of metal equivalent values should be | ||||
| clearly stated. | ||||
| Relationship | | These relationships are particularly | | Mineralisation is flat-lying to less than 4deg. |
| between | important in the reporting of Exploration | dip, vertical drill holes therefore approximate | ||
| mineralisation | Results. | true thickness. | ||
| widths and | | If the geometry of the mineralisation | | Refer to diagrams in the body of the |
| intercept | with respect to the drill hole angle is | announcement for visual representation of | ||
| lengths | known, its nature should be reported. | drill hole orientation vs. deposit orientation, | ||
| | If it is not known and only the down | note the vertical exaggeration used. | ||
| hole lengths are reported, there should | ||||
| be a clear statement to this effect (eg | ||||
| ‘down hole length, true width not | ||||
| _known’). _ | ||||
| Diagrams | | Appropriate maps and sections (with | | See body of announcement for plan and |
| scales) and tabulations of intercepts | cross section views and Mineral Resource | |||
| should be included for any significant | tabulations. | |||
| discovery being reported These should | ||||
| include, but not be limited to a plan | ||||
| view of drill hole collar locations and | ||||
| appropriate sectional views. | ||||
| Balanced | | Where comprehensive reporting of all | | All information considered material to the |
| reporting | Exploration Results is not practicable, | reader’s understanding of the database, | ||
| representative reporting of both low | estimation procedure and classification of the | |||
| and high grades and/or widths should | Mineral Resource has been reported. | |||
| be practiced to avoid misleading | ||||
| reporting of Exploration Results. | ||||
| Other | | Other exploration data, if meaningful | | Sheffield has previously reported deposit |
| substantive | and material, should be reported | information for Thunderbird including a | ||
| exploration | including (but not limited to): | maiden Mineral Resource estimate | ||
| data | geological observations; geophysical | (December 2012), Mineral Resource Updates | ||
| survey results; geochemical survey | (March, 2014 and December 2014), Scoping | |||
| results; bulk samples – size and method | Study results (April, 2104) and Pre-feasibility | |||
| of treatment; metallurgical test results; | Studyresults(May2015). These include |
- 20 -
| Criteria | Statement | Statement | Commentary | Commentary |
|---|---|---|---|---|
| bulk density, groundwater, | information on mineral assemblage, mineral | |||
| geotechnical and rock characteristics; | processing, VHM product recoverability, | |||
| potential deleterious or contaminating | quality and marketability and mining and | |||
| substances. | financial performance. | |||
| | Where relevant this information has been | |||
| included in the bodyof this announcement. | ||||
| Further work | | The nature and scale of planned | | Further work comprising closer-spaced drilling |
| further work (eg tests for lateral | is in progress. | |||
| extensions or depth extensions or large- | | Sheffield announced results from its PFS for | ||
| scale step-out drilling). | Thunderbird on 15 May, 2015. Following from | |||
| | Diagrams clearly highlighting the areas | this, a PFS Update is in progress and is | ||
| of possible extensions, including the | scheduled for completion in Q4 2015. This will | |||
| main geological interpretations and | incorporate results from the updated Mineral | |||
| future drilling areas, provided this | Resource reported in this announcement. | |||
| information is not commercially | ||||
| sensitive. |
Section 3 Estimation and Reporting of Mineral Resources
(Criteria listed in section 1, and where relevant in section 2, also apply to this section)
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| Database | | Measures taken to ensure that data | | Drill hole data was extracted directly from the |
| integrity | has not been corrupted by, for | Company’s drill hole database which | ||
| example, transcription or keying errors, | includes internal data validation protocols. | |||
| between its initial collection and its use | | Where necessary, original drill hole log files are | ||
| for Mineral Resource estimation | consulted to rectify any errors identified. | |||
| purposes. | | Validation of the exported data was | ||
| | Data validation procedures used. | confirmed using mining software (Micromine) | ||
| validation protocols, and visually in plan and | ||||
| section views. | ||||
| | Compilation of data external to the drill | |||
| database (eg. HM assemblage source data) | ||||
| is cross-checked manually, and through | ||||
| statistical comparison. | ||||
| | A copy (“snapshot”) of the Mineral Resource | |||
| database is retained separately to the | ||||
| primary drill hole database. | ||||
| | Data is further verified and validated by QG | |||
| Australia upon receipt, and prior to use in the | ||||
| estimation. | ||||
| Site visits | | Comment on any site visits undertaken | | Mr Teakle has visited the Thunderbird site and |
| by the Competent Person and the | the primary assay laboratory on numerous | |||
| outcome of those visits. | occasions during 2012, 2013 and 2014, during | |||
| | If no site visits have been undertaken | operations. | ||
| indicate why this is the case. | | Mr Strickland inspected the Thunderbird site | ||
| and the primary assay laboratory in 2013, | ||||
| during operations. | ||||
| | Where material, information relating to | |||
| observations from these visits has been | ||||
| included in this announcement. | ||||
| Geological | | Confidence in (or conversely, the | | As described above, Sheffield geologists have |
| interpretation | uncertainty of) the geological | defined five stratigraphic units within the | ||
| interpretation of the mineral deposit. | deposit area using a combination of surface | |||
| | Nature of the data used and of any | mapping and drill hole lithological logs. For | ||
| assumptions made. | the purposes of resource estimation, these | |||
| | The effect, if any, of alternative | units were used in combination with grade | ||
| interpretations on Mineral Resource | criteria to define four mineralised domains, as | |||
| estimation. | follows: | |||
| | The use of geology in guiding and | - B1 (north) and B2 (south): within Reeves | ||
| controlling Mineral Resource estimation. | Fm., grade criteria >1% HM, >6m width, | |||
| | The factors affecting continuity both of | >6m separation stratigraphicallyabove |
- 21 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| grade and geology. | the Thunderbird Fm. | |||
| - T1: Thunderbird Fm., grade criteria: HM >1- | ||||
| 2% and <7.5-10%, >6m width, <6m internal | ||||
| waste | ||||
| - T2: Thunderbird Fm. GT Zone within T1, | ||||
| grade criteria HM >7.5-10%, >6m width, | ||||
| <6m internal waste, marked change in HM | ||||
| grade at boundary | ||||
| Domain boundaries are guided by grade | ||||
| rules; however geological continuity overrides | ||||
| grade rules where necessary. It is useful to | ||||
| note however that primary HM% (and SL% | ||||
| and OS%) is a physical characteristic of the | ||||
| geological units related to unit deposition. | ||||
| | There is good confidence in the geological | |||
| interpretation of the deposit. Logged data | ||||
| from 560 drillholes as well as surface geology | ||||
| has been used to develop the interpretation | ||||
| and this is supported by HM%, SL% and OS% | ||||
| assays. The result is excellent geological (and | ||||
| grade) continuity in the model (see diagrams | ||||
| above), as expected for this style of HM | ||||
| deposit. | ||||
| | Examination of grade shells and the resource | |||
| grade-tonnage curve indicate the greatest | ||||
| change in the deposit in terms of tonnage vs | ||||
| grade occurs between cutoff grades of 2.5 | ||||
| and 5.5%HM. Also, the deposit outline remains | ||||
| coherent up to 14% HM cutoff. These | ||||
| thresholds are well within the corresponding | ||||
| geological domains and so changes to these | ||||
| domains through alternative interpretations | ||||
| are unlikely to significantly affect the Mineral | ||||
| Resource as reported. | ||||
| | The resource T1 domain imposes an | |||
| approximately 1-2% HM cutoff on the | ||||
| resource, and at its upper boundary | ||||
| corresponds closely with a natural geological | ||||
| boundary (between Reeves and Thunderbird | ||||
| Formations). This allows higher cutoff grades | ||||
| (eg. 3% as reported) to be applied and as | ||||
| such any change to this boundary is unlikely | ||||
| to significantly affect the Mineral Resource as | ||||
| reported. | ||||
| Dimensions | | The extent and variability of the Mineral | |
At 3% HM cut-off the resource block model |
| Resource expressed as length (along | covers an area about 8.5km long by 3km to | |||
| strike or otherwise), plan width, and | 6.5km wide, and remains open in all | |||
| depth below surface to the upper and | directions. The mineralisation occurs as a | |||
| lower limits of the Mineral Resource. | thick, broad anticlinal sheet-like body striking | |||
| northwest, extending from surface to a | ||||
| maximum depth of up to 155m. For the main | ||||
| body of the resource (ie. excluding small | ||||
| isolated pods of mineralisation) the average | ||||
| depth to the top of mineralisation is 36m | ||||
| (range 0m to 134m) and the average | ||||
| mineralised thickness is 38m (range 3m to | ||||
| 86m). The dip of the deposit changes from flat | ||||
| to low angle along the north-eastern flank, to | ||||
| 4 degrees along the south-western flank, | ||||
| resulting in around 30% of the total resource | ||||
| area occurringwithin 6m of surface. |
- 22 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| | At 7.5% HM cut-off the resource block model | |||
| covers an area about 7.5km long by 2.5km to | ||||
| 6.5km wide, and remains open to the north | ||||
| and south. The mineralisation follows the dip | ||||
| of the resource above 3% HM but strikes north- | ||||
| south, extending from surface to a maximum | ||||
| depth of 126m. For the main body of the | ||||
| resource (ie. excluding small isolated pods of | ||||
| mineralisation) the average depth to the top | ||||
| of mineralisation is 35m (range 0m to 92m) | ||||
| and the average mineralised thickness is 16m | ||||
| (range 3m to 44m). Approximately 26% of the | ||||
| >7.5% HM resource area is within 15m of | ||||
| surface. | ||||
| Estimation | | The nature and appropriateness of the | | Heavy mineral (HM), slime, oversize, zircon, HiTi |
| and | estimation technique(s) applied and | leucoxene, leucoxene, ilmenite, monazite | ||
| modelling | key assumptions, including treatment of | and ‘other’ material percentages were | ||
| techniques | extreme grade values, domaining, | estimated using ordinary kriging (OK) into | ||
| interpolation parameters and | blocks of dimension 62.5m East, by 125m | |||
| maximum distance of extrapolation | North by 3m RL. These block dimensions were | |||
| from data points. If a computer assisted | selected to reflect the variability of the | |||
| estimation method was chosen include | deposit, as a concession between the drill | |||
| a description of computer software | density and the model’s practicality for future | |||
| and parameters used. | mine planning. Sub-cells to a minimum | |||
| | The availability of check estimates, | dimension of 12.5m E by 25m N by 1m RL were | ||
| previous estimates and/or mine | used to represent volume. | |||
| production records and whether the | | The nominal drill spacing is approximately | ||
| Mineral Resource estimate takes | 250m x 500m with the margins of the deposit | |||
| appropriate account of such data. | drilled at a spacing of 500m x 500m and | |||
| | The assumptions made regarding | 1000m x 500m. Infill drilling in the area where | ||
| recovery of by-products. | the high grade domain outcrops at surface, | |||
| | Estimation of deleterious elements or | conducted as part of the 2014 drilling | ||
| other non-grade variables of economic | campaign, has reduced the nominal spacing | |||
| significance (eg sulphur for acid mine | to 125m x 250m. Four separate close-spaced | |||
| drainage characterisation). | ‘crosses’ have been drilled at a nominal | |||
| | In the case of block model | spacing of 60m both along and across strike. | ||
| interpolation, the block size in relation | | Exploratory data analysis and estimation was | ||
| to the average sample spacing and | undertaken in Isatis software. | |||
| the search employed. | | Drill samples were composited to 3m for | ||
| | Any assumptions behind modelling of | estimation. | ||
| selective mining units. | | New wireframe solid model interpretations of | ||
| | Any assumptions about correlation | mineralisation were made by SFX based on | ||
| between variables. | geological logging and heavy mineral (HM) | |||
| | Description of how the geological | content, using thresholds of ~1% HM to define | ||
| interpretation was used to control the | a low grade domain and 7.5% HM to define a | |||
| resource estimates. | high grade domain. QG assessed the | |||
| | Discussion of basis for using or not using | robustness of these domains by critically | ||
| grade cutting or capping. | examining the geological interpretation and | |||
| | The process of validation, the checking | using a variety of measures including | ||
| process used, the comparison of model | statistical and geostatistical analysis. The | |||
| data to drill hole data, and use of | domains are considered geologically robust in | |||
| reconciliation data if available. | the context of the resource classification | |||
| applied to the estimate. Hard boundaries | ||||
| were applied to estimation within | ||||
| mineralisation domains. | ||||
| | Maximum extrapolation distance considered | |||
| in grade domain determination was 1000m; | ||||
| however, this was reduced to, on average, | ||||
| 250m through the classification of the | ||||
| resource. | ||||
| | All variables were estimated separatelyand |
- 23 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| independently. | ||||
| | Grade capping was applied to HM% (waste | |||
| only), slime% and oversize%. The cap-values | ||||
| were based on examination of the tail of the | ||||
| histogram. | ||||
| | Estimation parameters were chosen after | |||
| taking into account output kriging estimation | ||||
| statistics, variogram models and data | ||||
| geometry. | ||||
| | The search used for the estimation of HM was | |||
| 1125m x 1500m x 150m (high grade domain), | ||||
| 1250m x 1250m x 150m (low grade and B1 | ||||
| domains), 1500m x 1500m x 150m (B2 | ||||
| domain), 1400m x 1150m x 150m (waste | ||||
| domain) with long axis oriented towards 310° | ||||
| and a 1.5° dip towards 220°. The estimation of | ||||
| slime used a search of 2800m x 1500m x 150m | ||||
| and oversize used a search of 3200m x 1600m | ||||
| x 150m in the same orientation. The search | ||||
| used a single sector with a minimum of six | ||||
| samples a maximum of 30 (low grade, B1 and | ||||
| B2 domains) or 40 (high grade, slime and | ||||
| oversize). | ||||
| | The optimum and maximum number of | |||
| samples used per drill hole was between two | ||||
| and four. | ||||
| | The searches used for the estimation of zircon | |||
| was 3200m x 2200m x 150m; ilmenite 2500m x | ||||
| 2000m x 150m (3000m x 2400m x 150m for B1 | ||||
| and B2 domains to populate the required | ||||
| number of blocks); HiTi leucoxene and | ||||
| leucoxene 2200m x 2000m x 150m (2800 x | ||||
| 2600m x 150 for B1 and B2 domains); monazite | ||||
| 3200m x 1500m x 150m or 3200m x 1800m x | ||||
| 150m depending on the mineral assemblage | ||||
| domain being estimated (3200m x 2500m x | ||||
| 150m for B1 and B2 domains); and ‘other’ | ||||
| material 3200m x 2500m x 150m. The long axis | ||||
| of the searches was orientated towards 310° | ||||
| and a 1.5° dip towards 220°. The search used | ||||
| a minimum of four samples and a maximum | ||||
| of 20. | ||||
| | Estimates were validated visually in | |||
| Minesight’s 3D graphical environment, by | ||||
| examining reproduction of global estimation | ||||
| statistics, and by comparing semi-local | ||||
| reproduction of grade in swath plots. | ||||
| Moisture | | Whether the tonnages are estimated | | Tonnages are estimated on a dry basis |
| on a dry basis or with natural moisture, | ||||
| and the method of determination of | ||||
| the moisture content. |
- 24 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| Cut-off | | The basis of the adopted cut-off | | The Mineral Resource estimate of the |
| parameters | grade(s) or quality parameters applied. | Thunderbird deposit has been reported at a | ||
| 3% HM and 7.5% HM cut-off. These cut-off | ||||
| grades were selected by SFX based on | ||||
| technical and economic assessment carried | ||||
| out during Scoping and Pre-Feasibility studies, | ||||
| and also by comparison with similar deposits | ||||
| currently or recently being mined in Australia | ||||
| and globally. QG have reviewed the | ||||
| parameters used to support these cut-offs | ||||
| grades and believe these to be reasonable. | ||||
| | At a 3% HM cut-off, the HM grade of the | |||
| Thunderbird Resource is 6.9%, and the in-situ | ||||
| VHM grade is approximately 2.9%. This | ||||
| compares favourably with other HMS deposits | ||||
| either recently or currently being mined. | ||||
| | The 7.5% HM cut-off is chosen to represent the | |||
| very-high grade, continuous component of | ||||
| the Mineral Resource, which may become | ||||
| the starting point of any future mining | ||||
| operations. In addition, spatially the 7.5% HM | ||||
| threshold is associated with a grade- | ||||
| geological boundary throughout the deposit, | ||||
| which was domained separately for the | ||||
| purposes of resource estimation. | ||||
| | The grade-tonnage curve is included in the | |||
| body of the announcement (Figure 8) to show | ||||
| the impact of cut-off grade versus total | ||||
| resource tonnage. | ||||
| Mining | | Assumptions made regarding possible | | In determining the reasonable prospects for |
| factors or | mining methods, minimum mining | eventual economic extraction, potential | ||
| assumptions | dimensions and internal (or, if | mining methods considered are either dry- | ||
| applicable, external) mining dilution. It | mining dozer-trap, or dredge mining | |||
| is always necessary as part of the | operations, similar to those commonly and | |||
| process of determining reasonable | currently in use in HM mining operations both | |||
| prospects for eventual economic | in Australia and globally. | |||
| extraction to consider potential mining | | The thickness, areal extent, and continuous | ||
| methods, but the assumptions made | nature of the mineralisation at Thunderbird | |||
| regarding mining methods and | are such that both selective and non- | |||
| parameters when estimating Mineral | selective bulk mining methods can be | |||
| Resources may not always be rigorous. | appropriately considered. | |||
| Where this is the case, this should be | | These assumptions were also considered | ||
| reported with an explanation of the | when determining resource block sizes, and | |||
| basis of the mining assumptions made. | resource classification. | |||
| | In addition, Sheffield has previously | |||
| announced positive financial results from | ||||
| Scoping and Pre-Feasibility Studies (see ASX | ||||
| release dated 14 April, 2014 and 14 May | ||||
| 2015). | ||||
| | On the basis of these assumptions, the | |||
| Company considers there are no mining | ||||
| factors which are likely to affect the | ||||
| assumption that the deposit has reasonable | ||||
| prospects for eventual economic extraction. | ||||
| Metallurgical | | The basis for assumptions or predictions | | As discussed earlier in this table, and in the |
| factors or | regarding metallurgical amenability. It | body of the announcement, the Company | ||
| assumptions | is always necessary as part of the | has conducted bulk process metallurgical | ||
| process of determining reasonable | studies on 6t, 5t and 12.5t bulk samples from | |||
| prospects for eventual economic | Thunderbird for the purpose of developing a | |||
| extraction to consider potential | process flowsheet for the deposit. The results | |||
| metallurgical methods, but the | of this work were used to design and optimise |
- 25 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| assumptions regarding metallurgical | the method used to determine the HM | |||
| treatment processes and parameters | assemblage reported in the Mineral Resource. | |||
| made when reporting Mineral | | The results of this work are sufficient for the | ||
| Resources may not always be rigorous. | Company to expect the Thunderbird | |||
| Where this is the case, this should be | mineralisation will be amenable to treatment | |||
| reported with an explanation of the | with conventional mineral sands processing | |||
| basis of the metallurgical assumptions | techniques. | |||
| made. | | Sheffield has previously announced positive | ||
| results relating to product processing and | ||||
| marketing in its Thunderbird Scoping and Pre- | ||||
| Feasibility Studies (see ASX release dated 14 | ||||
| April, 2014 and 14 May 2015). | ||||
| | On the basis of these studies, the Company | |||
| considers there are no metallurgical factors | ||||
| which are likely to affect the assumption that | ||||
| the deposit has reasonable prospects for | ||||
| eventual economic extraction. | ||||
| Environmen- | | Assumptions made regarding possible | | The Company has completed Level 1 and |
| tal factors or | waste and process residue disposal | Level 2 flora and fauna surveys at | ||
| assumptions | options. It is always necessary as part of | Thunderbird, and preliminary hydrogeological | ||
| the process of determining reasonable | investigations. | |||
| prospects for eventual economic | | On the basis of these studies, the Company | ||
| extraction to consider the potential | considers there are no environmental factors | |||
| environmental impacts of the mining | which are likely to affect the assumption that | |||
| and processing operation. While at this | the deposit has reasonable prospects for | |||
| stage the determination of potential | eventual economic extraction. | |||
| environmental impacts, particularly for | ||||
| a greenfields project, may not always | ||||
| be well advanced, the status of early | ||||
| consideration of these potential | ||||
| environmental impacts should be | ||||
| reported. Where these aspects have | ||||
| not been considered this should be | ||||
| reported with an explanation of the | ||||
| environmental assumptions made. | ||||
| Bulk density | | Whether assumed or determined. If | | No direct measurements of bulk density have |
| assumed, the basis for the assumptions. | been taken. | |||
| If determined, the method used, | | Bulk density is assumed from an industry- | ||
| whether wet or dry, the frequency of | standard formula which accounts for the HM | |||
| the measurements, the nature, size and | and slimes content of sand deposits. The | |||
| representativeness of the samples. | resultant values are considered to be | |||
| | The bulk density for bulk material must | consistent with observations of the material | ||
| have been measured by methods that | compared with other HM deposits with known | |||
| adequately account for void spaces | bulk density values. | |||
| (vugs, porosity, etc), moisture and | ||||
| differences between rock and | ||||
| alteration zones within the deposit. | ||||
| | Discuss assumptions for bulk density | |||
| estimates used in the evaluation | ||||
| process of the different materials. | ||||
| Classification | | The basis for the classification of the | | The estimate has been classified according to |
| Mineral Resources into varying | definitions of the JORC Code (2012), into | |||
| confidence categories. | Measured, Indicated and Inferred Resources | |||
| | Whether appropriate account has | taking into account data quality, data | ||
| been taken of all relevant factors (ie | density, geological continuity, grade | |||
| relative confidence in tonnage/grade | continuity and confidence in estimation of | |||
| estimations, reliability of input data, | heavy mineral content and mineral | |||
| confidence in continuity of geology | assemblage. In plan, polygons were used to | |||
| and metal values, quality, quantity and | define zones of different classification. | |||
| distribution of the data). | | Measured Resources encompass an area | ||
| | Whether the result appropriately | inclusive of the 125m x 250m infill drillingand |
- 26 -
| Criteria | JORC Code explanation | JORC Code explanation | Commentary | Commentary |
|---|---|---|---|---|
| reflects the Competent Person’s view | the four separate ‘crosses’ of close-spaced | |||
| of the deposit. | drilling, where drill spacing is 60m along strike | |||
| and 60m across strike. | ||||
| | Indicated Resources are defined where | |||
| drilling is at 500m centres along strike, by 250m | ||||
| or better. | ||||
| | Inferred Resources are defined around the | |||
| margins of Indicated Resource, where the drill | ||||
| spacingis reduced to 500m x 500m. | ||||
| Audits or | | The results of any audits or reviews of | | The Mineral Resource has been audited |
| reviews | Mineral Resource estimates. | internally as part of normal validation | ||
| processes both by the Company and QG. | ||||
| | No external audit or review of the Mineral | |||
| Resource has been conducted. | ||||
| Discussion of | | Where appropriate a statement of the | | The relative accuracy of the Mineral Resource |
| relative | relative accuracy and confidence | estimate is reflected in the level of | ||
| accuracy/ | level in the Mineral Resource estimate | classification applied, which takes into | ||
| confidence | using an approach or procedure | account metrics of estimation quality. | ||
| deemed appropriate by the | | Global estimates of tonnage and heavy | ||
| Competent Person. For example, the | mineral content are considered to have a | |||
| application of statistical or | high level of confidence. Local estimates are | |||
| geostatistical procedures to quantify | inevitably less confident, but the relative level | |||
| the relative accuracy of the resource | of risk is considered low, with the relative level | |||
| within stated confidence limits, or, if | of risk reflected by classification. | |||
| such an approach is not deemed | | The factors considered to present relatively | ||
| appropriate, a qualitative discussion of | higher sources of risk in the estimate are data | |||
| the factors that could affect the | quality and mineral assemblage. Geological | |||
| relative accuracy and confidence of | interpretation and estimation are considered | |||
| the estimate. | to present low risk. | |||
| | The statement should specify whether it | |
No production has occurred from the deposit. | |
| relates to global or local estimates, | ||||
| and, if local, state the relevant | ||||
| tonnages, which should be relevant to | ||||
| technical and economic evaluation. | ||||
| Documentation should include | ||||
| assumptions made and the procedures | ||||
| used. | ||||
| | These statements of relative accuracy | |||
| and confidence of the estimate should | ||||
| be compared with production data, | ||||
| where available. |
- 27 -
Appendix 2: QG Thunderbird Mineral Resource Statement Memorandum
- Following pages (p28 to p33) -
==> picture [596 x 263] intentionally omitted <==
Memorandum
To: Sheffield Resources Ltd From: Trent Strickland
Date: 30 July 2015 Subject: Thunderbird Mineral Sands Deposit Resource Statement
This document presents the Mineral Resource Statement for the Thunderbird deposit, Western Australia.
Thunderbird Mineral Resource Statement
QG Australia Pty Ltd (QG) has provided Sheffield Resources Ltd (SFX) with a resource model for the Thunderbird heavy mineral sands deposit. The estimate is based on aircore (AC) and reverse circulation (RC) drilling data collected by SFX in 2012, 2013 and 2014.
The Thunderbird deposit is located within the Canning Basin in the Kimberley region of Western Australia. Thunderbird is a heavy mineral sand (HMS) deposit hosted by deeply weathered Cretaceous sand formations. At a 3% HM cut-off the Resource covers an area which is 8.5km along strike and at least 3km to 6.5km wide, and remains open in most directions. Mineralisation occurs from surface to depths of up to 155m, with an average depth to the top of the main body of mineralisation of 36m, and an average mineralised thickness of 38m. The areal extent, width, grade, geological continuity and grainsize of the Thunderbird mineralisation are suggestive of an off-shore, sub-wave base depositional environment.
The drill database used to define the mineral resource comprises 560 vertical AC and RC drillholes, for a total of 33,608.5m, with 22,378 samples assayed totalling 33,453.4m. Of that,
==> picture [548 x 67] intentionally omitted <==
- 29 -
13,030 assayed samples totalling 19,460.4m are within the mineralised zones of the resource.
The nominal drill spacing is approximately 250m x 500m with the margins of the deposit drilled at a spacing of 500m x 500m and 1000m x 500m. Infill drilling in the area where the high grade domain outcrops at surface, conducted as part of the 2014 drilling campaign, has reduced the nominal spacing to 125m x 250m. Four separate close-spaced ‘crosses’ have been drilled at a nominal spacing of 60m both along and across strike.
QG have reviewed the quality of drill data (location, recovery, sampling and assay quality) and conclude that the data is of acceptable quality for use in resource estimation and subsequent mine planning.
New wireframe solid model interpretations of mineralisation were made by SFX based on geological logging and heavy mineral (HM) content, using thresholds of ~1% HM to define a low grade domain and 7.5% HM to define a high grade domain. QG assessed the robustness of these domains by critically examining the geological interpretation and using a variety of measures including statistical and geostatistical analysis. The domains are considered geologically robust in the context of the resource classification applied to the estimate.
Ordinary Kriging was used to estimate HM%, slime% and oversize%. The search neighbourhood employed was optimised using Quantitative Kriging Neighbourhood Analysis (QKNA). Density was calculated per block. Hard boundaries were applied to estimation within mineralisation domains. Grade capping was applied to slime% and oversize%. The cap values were based on examination of the tail of the histogram and local grade distribution.
The mineral assemblage of the Thunderbird mineral resource was estimated from mineralogical analyses of 702 composites created from 331 holes totalling 13,454m from the 2013 and 2014 drilling programs. Analysis was by a combination of screening, magnetic separation followed by QEMSCAN analysis of the magnetic component, and XRF determination of the non-magnetic component. Details of mineralogical calculations are provided in the footnotes to resource tabulations. The mineralogical data was also supplemented with the average mineralogy of a 6t bulk sample, sourced from the 2012 ‘cross’ of 60m spaced drilling. The composites consisted of samples taken from discrete intervals from within five geological units across multiple holes and combined. The composites were well distributed throughout the deposit. Ordinary Kriging was used to estimate zircon%, high titanium (‘HiTi’) leucoxene %, leucoxene %, ilmenite %, monazite % and other material %.
The estimate was validated by QG as follows:
-
Visual checking of the interpolation results compared with drilling in both plan and section;
-
Comparison of the global input (composites) vs. output (model) statistics, including clustered and declustered composites; and
Semi-local input vs. output statistics using moving window averages.
The estimate is considered to be robust on the basis of the above checks.
The estimate has been classified according to the definitions of the JORC Code (2012), into Measured, Indicated and Inferred Resources taking into account data quality, data density, geological continuity, grade continuity and confidence in estimation of heavy mineral content
==> picture [595 x 91] intentionally omitted <==
- 30 -
and mineral assemblage. In plan, polygons were used to define zones of different classification. Measured Resources encompass an area inclusive of the 125 x 250m infill drilling and the four separate ‘crosses’ of close-spaced drilling, where drill spacing is 60m along strike and 60m across strike. Indicated Resources are defined where drilling is at 500m centres along strike, by 250m or better. Inferred Resources are defined around the margins of Indicated Resource, where the drill spacing is reduced to 500m x 500m.
The Thunderbird mineral resource estimate has been reported at both a 3% HM and a 7.5% HM cut-off. These cut-off grades were selected by SFX based on technical and economic assessment carried out during the Pre-Feasibility study, and on comparison with similar deposits currently or recently being mined. Refer to the ASX announcement “Pre-Feasibility study confirms Thunderbird as next major mineral sands project in global development pipeline” dated 14[th] May 2015 for further details, including the parameters used during pit optimisation. The announcement is available on Sheffield Resources Ltd’s web site www.sheffieldresources.com.au. Based on the same technical and economic assessment, and taking into consideration the thickness, grades and depth of the deposit, it is considered that the entire deposit has a reasonable prospect of eventually being mined, and that the current extents of the deposit are limited by drilling. The Thunderbird mineral resource estimate, as at the 30[th] July 2015, is summarised in Table 1 and Table 2.
==> picture [595 x 91] intentionally omitted <==
- 31 -
| Mineral Resource Category |
Material Million Tonnes1 |
Bulk Density | HM % | Slimes % | Osize % | In-situ HM Million Tonnes1 |
|---|---|---|---|---|---|---|
| Measured | 230 | 2.1 | 9.4 | 19 | 10 | 21 |
| Indicated | 2,410 | 2.0 | 6.9 | 16 | 8 | 167 |
| Inferred | 600 | 2.0 | 5.6 | 16 | 9 | 33 |
| TOTAL | 3,240 | 2.1 | 6.9 | 16 | 9 | 222 |
| Mineral Resource Category |
Material Million Tonnes1 |
HM % | Valuable HM Grade (% In-situ)2 | |||
| Zircon | HiTi Leucoxene | Leucoxene | Ilmenite | |||
| Measured | 230 | 9.4 | 0.74 | 0.21 | 0.20 | 2.5 |
| Indicated | 2,410 | 6.9 | 0.58 | 0.19 | 0.22 | 1.9 |
| Inferred | 600 | 5.6 | 0.47 | 0.16 | 0.20 | 1.5 |
| TOTAL | 3,240 | 6.9 | 0.57 | 0.18 | 0.21 | 1.9 |
| Mineral Resource Category |
In-situ HM Million Tonnes1 |
Mineral Assemblage (as % of HM Tonnes )3 | ||||
| Zircon | HiTi Leucoxene | Leucoxene | Ilmenite | Valuable HM% | ||
| Measured | 21 | 7.9 | 2.2 | 2.1 | 27 | 39 |
| Indicated | 167 | 8.4 | 2.7 | 3.1 | 28 | 42 |
| Inferred | 33 | 8.4 | 2.8 | 3.5 | 28 | 42 |
| TOTAL | 222 | 8.3 | 2.7 | 3.1 | 28 | 42 |
1 All tonnages and grades hav e been rounded to reflect the relativ e uncertainty of the estimate, thus sum of columns may not equal. 2 The In-situ grade is determined by multiplying the percentage of HM by the percentage of each v aluable heav y mineral within the heav y mineral assemblage. 3 Estimates of Mineral Assemblage are presented as percentages of the Heav y Mineral (HM) component of the deposit, as determined by magnetic separation, QEMSCAN and XRF. Magnetic fractions were analysed by QEMSCAN for mineral determination as follows: Ilmenite: 40-70% TiO2 >90% Liberation; Leucoxene: 70-94% TiO2 >90% Liberation; High Titanium Leucoxene (HiTi Leucoxene): >94% TiO2 >90% Liberation; and Zircon: 66.7% ZrO2+HfO2 >90% Liberation. The non-magnetic fraction was submitted for XRF analysis and minerals determined as follows: Zircon: ZrO2+HfO2/0.667 and High Titanium Leucoxene (HiTi Leucoxene): TiO2/0.94.
==> picture [595 x 91] intentionally omitted <==
Table 1. Thunderbird Mineral Resource Estimate at a cut-off grade of 3% HM.
- 32 -
| Mineral Resource Category |
Material Million Tonnes1 |
Bulk Density | HM % | Slimes % | Osize % | In-situ HM Million Tonnes1 |
|---|---|---|---|---|---|---|
| Measured | 110 | 2.2 | 14.9 | 17 | 13 | 16 |
| Indicated | 850 | 2.1 | 11.8 | 15 | 10 | 100 |
| Inferred | 130 | 2.0 | 10.7 | 14 | 9 | 14 |
| TOTAL | 1,090 | 2.1 | 11.9 | 15 | 10 | 131 |
| Mineral Resource Category |
Material Million Tonnes1 |
HM % | Valuable HM Grade (% In-situ)2 | |||
| Zircon | HiTi Leucoxene | Leucoxene | Ilmenite | |||
| Measured | 110 | 14.9 | 1.09 | 0.31 | 0.28 | 4.0 |
| Indicated | 850 | 11.8 | 0.90 | 0.28 | 0.25 | 3.3 |
| Inferred | 130 | 10.7 | 0.82 | 0.25 | 0.23 | 3.0 |
| TOTAL | 1,090 | 11.9 | 0.91 | 0.28 | 0.25 | 3.3 |
| Mineral Resource Category |
In-situ HM Million Tonnes1 |
Mineral Assemblage (as % of HM Tonnes )3 | ||||
| Zircon | HiTi Leucoxene | Leucoxene | Ilmenite | Valuable HM% | ||
| Measured | 16 | 7.3 | 2.1 | 1.9 | 27 | 38 |
| Indicated | 100 | 7.6 | 2.4 | 2.2 | 28 | 40 |
| Inferred | 14 | 7.6 | 2.3 | 2.2 | 28 | 40 |
| TOTAL | 131 | 7.6 | 2.3 | 2.1 | 28 | 40 |
1 All tonnages and grades hav e been rounded to reflect the relativ e uncertainty of the estimate, thus sum of columns may not equal. 2 The In-situ grade is determined by multiplying the percentage of HM by the percentage of each v aluable heav y mineral within the heav y mineral assemblage. 3 Estimates of Mineral Assemblage are presented as percentages of the Heav y Mineral (HM) component of the deposit, as determined by magnetic separation, QEMSCAN and XRF. Magnetic fractions were analysed by QEMSCAN for mineral determination as follows: Ilmenite: 40-70% TiO2 >90% Liberation; Leucoxene: 70-94% TiO2 >90% Liberation; High Titanium Leucoxene (HiTi Leucoxene): >94% TiO2 >90% Liberation; and Zircon: 66.7% ZrO2+HfO2 >90% Liberation. The non-magnetic fraction was submitted for XRF analysis and minerals determined as follows: Zircon: ZrO2+HfO2/0.667 and High Titanium Leucoxene (HiTi Leucoxene): TiO2/0.94.
Table 2. Thunderbird Mineral Resource Estimate at a cut-off grade of 7.5% HM.
Yours faithfully,
==> picture [113 x 41] intentionally omitted <==
Trent Strickland Senior Consultant
==> picture [595 x 91] intentionally omitted <==
- 33 -
Competent Persons Statements
The information in this report that relates to the estimation of Mineral Resources is based on information compiled by Mr Trent Strickland, who is a Member of the Australasian Institute of Mining and Metallurgy (AusIMM). Mr Strickland is a full time employee of QG Australia Pty Ltd and has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2012 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Mr Strickland consents to the inclusion in this report of the matters based on his information in the form and context in which it appears.
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