DUKETON MINING LIMITED — Capital/Financing Update 2023

May 21, 2023

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ASX Announcement 22 May 2023

Nickel Results confirm Rosie Continues

HIGHLIGHTS Diamond Drilling – Duketon Nickel Project (100% DKM)

• Assays received for the 6 hole diamond program completed last month at the Bulge Ultramafic Complex

• • Significant intercepts at Rosie include: o 9.18m @ 1.49% Ni, 0.31% Cu & 1.94g/t Pt + Pd (DKDD0039) inc.  2.13m @ 3.12% Ni, 0.34% Cu & 5.45g/t Pt + Pd and  1.86m @ 2.28% Ni, 0.68% Cu & 1.84g/t Pt + Pd

• o 2.53m @ 1.55% Ni, 0.18% Cu & 1.52g/t Pt + Pd (DKDD0036) o 1.27m @ 1.8% Ni, 0.2% Cu & 0.97g/t Pt + Pd (DKDD0038)

• • DKDD0039 returned individual grades up to 12.5g/t Palladium, 3.4% Nickel and 2.7% Copper , intersecting mineralisation 50 metres down dip of the current Rosie resource

• • Significant intercepts at Rosie West include: o 5.8m @ 0.67% Ni, 0.09% Cu & 0.7g/t Pt + Pd (DKDD0035) inc.  0.5m @ 3.87% Ni, 0.43% Cu & 2.9g/t Pt + Pd and further downhole

• o 0.45m @ 1.95% Ni, 0.16% Cu & 1.7g/t Pt + Pd

• • Holes submitted for remaining elements of PGE suite. • Down hole EM indicates Rosie mineralisation continues at depth • Drill results will extend the Rosie resource down dip • RC drill rig scheduled to be back on site next week with 4,000m program at the Bulge

Duketon Mining Limited (ASX: DKM) (“Duketon” or “the Company”) is pleased to announce assays have been received for the diamond drilling completed earlier this year at the Bulge Ultramafic Complex (see ASX Announcements 28 February and 21 April 2023).

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Significant intercepts at Rosie include:

• 9.18m @ 1.49% Ni, 0.31% Cu & 1.94g/t Pt + Pd (DKDD0039) inc.

• 2.13m @ 3.12% Ni, 0.34% Cu & 5.45g/t Pt + Pd and

• 1.86m @ 2.28% Ni, 0.68% Cu & 1.84g/t Pt + Pd

• 2.53m @ 1.55% Ni, 0.18% Cu & 1.52g/t Pt + Pd (DKDD0036)

• 1.27m @ 1.8% Ni, 0.2% Cu & 0.97g/t Pt + Pd (DKDD0038)

Significant intercepts at Rosie West include:

• 5.8m @ 0.67% Ni, 0.09% Cu & 0.7g/t Pt + Pd inc.

• 0.5m @ 3.87% Ni, 0.43% Cu & 2.9g/t Pt + Pd and further downhole

• o 0.45m @ 1.95% Ni, 0.16% Cu & 1.7g/t Pt + Pd

This drill program focussed on exploration targets and extensions to known mineralisation within the greater Bulge Ultramafic Complex. Six holes were drilled in total for 3400 metres. Two holes were drilled at Rosie West, located approximately 350m west of Rosie, two drilled at depth below Rosie and two drilled testing the south-eastern and northern limits of the Rosie resource.

The two holes drilled at depth below the known limits of Rosie, DKDD0036 and DKDD0039, intersected significant mineralisation, beneath the current JORC resource (approximately 50m) and will increase the resource tonnes. Downhole electromagnetic (DHEM) from these drillholes indicate mineralisation continues at depth to the south-east.

At Rosie West mineralisation was intersected in DKDD0035 with 2 small, high-grade intervals of nickel mineralisation. This mineralisation is 270m beneath previous historical intersections (ASX 16 February 2023) and indicates a significant exploration step as it indicates that high grade nickel, copper, PGE sulphides are present on the Rosie West Contact. Exploration will continue in this area.

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Figure 1: Cross section of DKDD0039, Rosie

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Figure 2: Cross section of DKDD0036, Rosie

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Figure 3: Rosie Long Section

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Figure 4: Cross section of DKDD0035, Rosie West

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Table 1: Rosie Significant Intercept Table (Significant intercepts are >4000 ppm Ni, maximum

internal dilution of 2 metres, intersections are downhole widths.)

Hole ID	Depth From (m)	Depth To (m)	Intercept Width (m)	Ni %	Cu %	Pt + Pd (g/t)	Comments
DKDD0036	583	584.05	1.05	0.54	0.08	0.42	1.05m@0.54% Ni,0.08% Cu & 0.42g/t Pt + Pd
and	605.5	608.03	2.53	1.55	0.18	1.52	2.53m@ 1.55% Ni, 0.18% Cu & 1.52g/t Pt + Pd
inc.	605.5	607.3	1.8	1.98	0.23	2.12	1.8m@ 1.98% Ni, 0.23% Cu & 2.12g/t Pt + Pd
DKDD0038	419.8	421.4	1.6	1.61	0.2	0.88	1.6m@ 1.61% Ni, 0.2% Cu & 0.88g/t Pt + Pd
inc.	419.8	421.07	1.27	1.8	0.2	0.97	1.27m@ 1.8% Ni, 0.2% Cu & 0.97g/t Pt + Pd
DKDD0039	626	627	1	0.4	0.04	0.31	1m@0.4% Ni,0.04% Cu & 0.31g/t Pt + Pd
and	647.2	656.38	9.18	1.49	0.31	1.94	9.18m@ 1.49% Ni, 0.31% Cu & 1.94g/t Pt + Pd
inc.	648.11	649.97	1.86	2.28	0.8	1.84	1.86m@ 2.28% Ni, 0.8% Cu & 1.84g/t Pt + Pd
inc.	651.13	653.26	2.13	3.12	0.34	5.45	2.13m@ 3.12% Ni, 0.34% Cu & 5.45g/t Pt + Pd

Table 2: Rosie West Significant Intercept Table (Significant intercepts are >4000 ppm Ni,

maximum consecutive dilution of 2 metres, intersections are downhole widths.)

Hole ID	Depth From (m)	Depth To (m)	Intercept Width (m)	Ni %	Cu %	Pt + Pd (g/t)	Comments
DKDD0035	496.5	502.3	5.8	0.67	0.09	0.7	5.8m @ 0.67% Ni, 0.09% Cu & 0.7g/t Pt + Pd
inc.	501.8	502.3	0.5	3.86	0.43	2.9	0.5m @ 3.86% Ni, 0.43% Cu & 2.9g/t Pt + Pd
and	526.4	526.85	0.45	1.95	0.16	1.7	0.45m @ 1.95% Ni, 0.16% Cu & 1.7g/t Pt + Pd

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Figure 5: Location map of the Duketon tenement holdings and location of the DKM prospects

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Table 3: Drillhole collar details

Hole ID	Easting (MGA 94 Z51)	Northing (MGA 94 Z51)	Nominal RL (m)	Dip (°)	Azimuth (mag °)	Total Depth (m)
DKDD0035	401936	6943716	550	-60	45	711
DKDD0036	402898	6943411	545	-60	0	651
DKDD0037	403176	6943699	540	-60	315	423
DKDD0038	401947	6944332	541	-60	45	447
DKDD0039	402748	6943402	542	-60	0	701.8
DKDD0040	401850	6943950	540	-60	45	500.9

Table 4: Rosie Mineral Resource

Rosie Nickel Resource >1% NiEq	Rosie Nickel Resource >1% NiEq	Rosie Nickel Resource >1% NiEq	Rosie Nickel Resource >1% NiEq	Rosie Nickel Resource >1% NiEq	Rosie Nickel Resource >1% NiEq	Rosie Nickel Resource >1% NiEq	Rosie Nickel Resource >1% NiEq
Classification	Sulphide	Tonnes	Ni (%)	Cu (%)	Co (ppm)	Total PGEs (g/t)	NiEq %
Indicated	Pentlandite	1,191,555	2.4	0.42	642	2.7	3.76
	Violarite	820,999	1.7	0.39	504	2.5	2.75
	Sub-Total	2,012,553	2.1	0.41	585	2.6	3.35
Inferred	Pentlandite	694,751	1.8	0.48	580	2.5	3.13
	Violarite	66,179	1.5	0.42	442	1.7	2.36
	Sub-Total	760,930	1.8	0.48	568	2.4	3.06
Total	All	2,773,483	2.0	0.43	580	2.6	3.27

Authorised for release by: Stuart Fogarty

Duketon Mining Limited - Managing Director +61 8 6315 1490

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Competent Person Statement:

The information in this release that relates to exploration results is based on information compiled by Ms Kirsty Culver, Member of the Australian Institute of Geoscientists (AIG) and an employee of Duketon Mining Limited. Ms Culver has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity that is being undertaken to qualify as a competent person as defined in the JORC Code 2012. Ms Culver consents to the inclusion in the report of the matters based on the information in the form and context in which it appears.

This release includes information that relates to exploration results which were prepared and first disclosed under the JORC Code 2012. The information was extracted from the Company’s previous ASX announcements as follows:

• 16 February 2023 Diamond Drilling Commencing at Duketon

• 28 February 2023 Sulphides Intersected West of Rosie

• 21 April 2023 Revised Announcement Sulphide Success at The Bulge

• 10 March 2022 Rosie Resource Increases in Tonnes, Grade and Metal

The Company confirms that it is not aware of any new information or data that materially affects the information included in the original market announcement. The Company confirms that the form and context in which any Competent Person’s findings are presented have not been materially modified from the original market announcement.

The information in the announcement that relates to Mineral Resources for Rosie is extracted from the ASX announcement 10 March 2022 and is available to view on the Company’s website (www.duketonmining.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 that all material assumptions and technical parameters underpinning the estimates in the relevant market announcements 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.

Duketon Mining Limited ACN 159 084 107 Level 2, 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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JORC Table 1

JORC Code, 2012 Edition – Table 1 report – Duketon Project

Section 1 Sampling Techniques and Data – Rosie Diamond Drilling

(Criteria in this section apply to all succeeding sections.)

Criteria	JORC Code explanation	Commentary
Sampling	• Nature and quality of sampling (eg cut channels, random chips, or	•Diamond core was drilled HQ to competent rock and then NQ2 to end
techniques	specific specialised industry standard measurement tools appropriate	of hole.
	to the minerals under investigation, such as down hole gamma	•The sample interval is cut in half using a diamond core saw and half
	sondes, or handheld XRF instruments, etc). These examples should	core sampled for assay. Each sample provides between 2.0-3.0kg of
	not be taken as limiting the broad meaning of sampling.	material. The core is cut to the left of the orientation line, with the
	• Include reference to measures taken to ensure sample representivity	same half sampled to ensure sample is representative.
	and the appropriate calibration of any measurement tools or systems	•Diamond core is sampled to geological boundaries, no more than
	used.	1.2m and no less than 20cm per sample.
	• Aspects of the determination of mineralisation that are Material to the	•Certified samples and blanks are inserted every 25thsample for
	Public Report.	diamond drilling.
	• In cases where ‘industry standard’ work has been done this would be	•Mineralisation is determined qualitatively by geological logging and
	relatively simple (eg ‘reverse circulation drilling was used to obtain 1	quantitatively through assaying.
	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, open-hole hammer, rotary air	•Diamond drilling using HQ2 (61.1mm) sized core to competent rock
techniques	blast, auger, Bangka, sonic, etc) and details (eg core diameter, triple	and then NQ2 (50.6mm) to end of hole.
	or standard tube, depth of diamond tails, face-sampling bit or other	•Core was oriented using the Axis Champ Orientation tool..
	type, whether core is oriented and if so, by what method, etc).

Duketon Mining Limited ACN 159 084 107 Level 2 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Criteria	JORC Code explanation	Commentary
Drill sample	• Method of recording and assessing core and chip sample recoveries	•Recoveries qualitatively noted at the time of drilling and recorded.
recovery	and results assessed.	•Core is metre marked and orientated. Run recoveries are recorded.
	• Measures taken to maximise sample recovery and ensure	•Triple tube HQ is used to maximise recovery through the weathered
	representative nature of the samples.	zone and ensure a representative sample.
	• 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.
Logging	• Whether core and chip samples have been geologically and	•All core is logged to a level of detail to support future use in a mineral
	geotechnically logged to a level of detail to support appropriate	resource calculation.
	Mineral Resource estimation, mining studies and metallurgical	•Qualitative: Lithology, alteration, mineralisation.
	studies.	•Quantitative: Vein percentage, sulphide percentage.
	• Whether logging is qualitative or quantitative in nature. Core (or	•All holes for their entire length are logged.
	costean, channel, etc) photography.	•All core is photographed.
	• The total length andpercentage of the relevant intersections logged.
Sub-	• If core, whether cut or sawn and whether quarter, half or all core	•The core is cut using an automatic core saw, half core is sampled.
sampling	taken.	•At the laboratory the core sample is crushed to <2mm and then
techniques	• If non-core, whether riffled, tube sampled, rotary split, etc and	pulverised to achieve 85% passing75 µm
and sample preparation	whether sampled wet or dry. • For all sample types, the nature, quality and appropriateness of the sample preparation technique.	•Field duplicates are collected within the mineralised zones and are samples as quarter core samples
	• 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.
Quality of	• The nature, quality and appropriateness of the assaying and	•Samples are analysed using a 4-acid digest and ICP_OES finish for
assay data	laboratory procedures used and whether the technique is considered	33 elements and Fire Assay 25g charge with MS finish for Au, Pt and
and	partial or total.	Pd.
	• Forgeophysical tools, spectrometers, handheld XRF instruments, etc,	•This technique is industrystandard for nickel and considered

Duketon Mining Limited ACN 159 084 107

Level 2 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Criteria	JORC Code explanation	Commentary
laboratory	the parameters used in determining the analysis including instrument	appropriate.
tests	make and model, reading times, calibrations factors applied and their	•Certified Reference Material (Standards) and blanks are submitted
	derivation, etc.	with batches (1 in every 25 samples).
	• Nature of quality control procedures adopted (eg standards, blanks,
	duplicates, external laboratory checks) and whether acceptable levels
	of accuracy (ie lack of bias) andprecision have been established.
Verification	• The verification of significant intersections by either independent or	•All data is checked internally for correctness by senior DKM
of sampling	alternative company personnel.	geological and corporate staff.
and	• The use of twinned holes.	•All data is collected via Ocris software and uploaded into the DKM
assaying	• Documentation of primary data, data entry procedures, data verification, data storage (physical and electronic) protocols.	Datashed Database following validation. •No twinned holes have been drilled to date.
	• Discuss any adjustment to assay data.
Location of	• Accuracy and quality of surveys used to locate drill holes (collar and	•All location points are collected using a handheld GPS in MGA 94 –
data points	down-hole surveys), trenches, mine workings and other locations	Zone 51
	used in Mineral Resource estimation.	•Downhole surveying (azimuth and dip of the drillhole) of diamond
	• Specification of the grid system used.	drillholes was measured by the drilling contractors using an Axis
	• Quality and adequacy of topographic control.	Champ North Seeking Gyro.
		•A topographic surface has been created from airborne geophysical
		data. Drillholes are corrected to this surface.
Data spacing	• Data spacing for reporting of Exploration Results.	•Holes are drilled at various spacing depending upon the holes drilled
and	• Whether the data spacing and distribution is sufficient to establish the	previously in the area of interest.
distribution	degree of geological and grade continuity appropriate for the Mineral	•Hole spacing is appropriate for drilling at this stage.
	Resource and Ore Reserve estimation procedure(s) and
	classifications applied.
	• Whether sample compositing has been applied.
Orientation	• Whether the orientation of sampling achieves unbiased sampling of	•The orientation of the geology and mineralization at Rosie is steeply
of data in	possible structures and the extent to which this is known, considering	dipping to the south and striking NNW to W.
relation to	the deposit type.	•The orientation of the geology and mineralization at Rosie West is
	• If the relationship between the drilling orientation and the orientation	steeply dipping to the north and striking NW to W.
	of key mineralised structures is considered to have introduced a

Duketon Mining Limited ACN 159 084 107 Level 2 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Criteria	JORC Code explanation	Commentary
geological	sampling bias, this should be assessed and reported if material.
structure
Sample	• The measures taken to ensure sample security.	•Chain of custody is managed by company representatives and is
security		considered appropriate. All samples are bagged in a tied numbered
		calico bag, grouped into larger polyweave bags and cable tied.
		Polyweave bags are placed into larger bulky bags with a sample
		submission sheet and tied shut. Consignment note and delivery
		address details are written on the side of the bag and delivered to Toll
		in Laverton. The bags are delivered directly to Intertek in Kalgoorlie,
		WA who are NATA accredited for compliance with
		ISO/IEC17025:2005.
Audits or	• The results of any audits or reviews of sampling techniques and data.	•No external audits or reviews have been conducted apart from
reviews		internal company review.

Section 2 Reporting of Exploration Results

(Criteria listed in the preceding section also apply to this section.)

Criteria	JORC Code explanation	Commentary
Mineral	• Type, reference name/number, location and ownership including	•The tenement (M38/1252) is 100% owned by Duketon Mining Limited
tenement and	agreements or material issues with third parties such as joint	and is in good standing and there are no known impediments to
land tenure	ventures, partnerships, overriding royalties, native title interests,	obtaining a licence to operate in the area.
status	historical sites, wilderness or national park and environmental settings.
	• The security of the tenure held at the time of reporting along with
	any known impediments to obtaining a licence to operate in the

Duketon Mining Limited ACN 159 084 107

Level 2 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Criteria	JORC Code explanation	Commentary
	area.
Exploration	• Acknowledgment and appraisal of exploration by other parties.	•Previous drilling at The Bulge Complex was completed by
done by other		Independence Group (IGO) and South Boulder Mines Ltd. This work
parties		has been checked for quality as far as possible and formed the basis of the follow-up conducted as part of the drilling programme
		presented.
Geology	• Deposit type, geological setting and style of mineralisation.	•The Rosie Nickel Deposit is a komatiite-hosted nickel sulphide
		deposit. The mineralisation is characterised by accumulations of
		massive, matrix, breccia and disseminated sulphides at the basal
		contact overlying a basalt footwall.
Drill hole	• A summary of all information material to the understanding of the	•A table is provided within the text of this announcement.
Information	exploration results including a tabulation of the following information
	for all Material drill holes:
	o easting and northing of the drill hole collar
	o elevation or RL (Reduced Level – elevation above sea level in
	metres) of the drill hole collar
	o dip and azimuth of the hole
	o down hole length and interception depth
	o hole length.
Data	• In reporting Exploration Results, weighting averaging techniques,	•No top-cuts have been applied when reporting results
aggregation	maximum and/or minimum grade truncations (eg cutting of high	•First assay from the interval in question is reported (i.e. Ni1)
methods	grades) and cut-off grades are usually Material and should be	•Aggregate sample assays calculated using a length weighted
	stated.	average
	• Where aggregate intercepts incorporate short lengths of high grade	•Significant grade intervals are based on intercepts > 4000ppm Ni
	results and longer lengths of low grade results, the procedure used	•Metal equivalents have not been reported
	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.

Duketon Mining Limited ACN 159 084 107 Level 2 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490

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Criteria	JORC Code explanation	Commentary
Relationship	• If the geometry of the mineralisation with respect to the drill hole	•Downhole length is reported for drillholes.
between	angle is known, its nature should be reported.	•Cross section contained in document shows approximate geometry
mineralisation	• If it is not known and only the down hole lengths are reported, there
widths and	should be a clear statement to this effect (eg ‘down hole length, true
intercept	width not known’).
lengths
Diagrams	• Appropriate maps and sections (with scales) and tabulations of	•Refer to figures in document.
	intercepts should be included for any significant 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 Exploration Results is not	•All drillhole locations are reported.
reporting	practicable, representative reporting of both low and high grades
	and/or widths should be practiced to avoid misleading reporting of
	Exploration Results.
Other	• Other exploration data, if meaningful and material, should be	•Refer to document.
substantive	reported including (but not limited to): geological observations;
exploration data	geophysical survey results; geochemical survey results; bulk samples – size and method of treatment; metallurgical test results; bulk density, groundwater, geotechnical and rock characteristics;
	potential deleterious or contaminating substances.
Further work	• The nature and scale of planned further work (eg tests for lateral	•A discussion of further work underway is contained within the body to
	extensions or depth extensions or large-scale step-out drilling).	this ASX release.
	• Diagrams clearly highlighting the areas of possible extensions,
	including the main geological interpretations and future drilling
	areas, provided this information is not commercially sensitive.

Duketon Mining Limited ACN 159 084 107 Level 2 25 Richardson Street West Perth WA 6005 T: +61 8 6315 1490