Operations

Mineral Reserves and Resources

Consolidated Estimated Mineral Resources

MINERAL RESOURCES – Inclusive of Mineral Reserves											CONTAINED METAL
	Category	kt	TCu %	SCu %	Zn %	Pb %	Mo %	Ag g/t	Au g/t	Fe %	Cu kt	Zn kt	Pb kt	Mo kt	Ag koz	Au koz	Fe³ mt
Pinto Valley¹ 31-Dec-2023	Measured	608,657	0.33				0.006				1,996			37
	Indicated	765,646	0.26				0.005				2,014			38
	M&I	1,374,303	0.29				0.005				4,010			75
	Inferred	149,789	0.27				0.006				410			9
Cozamin² 31-Dec-2023	Measured	400	1.25		1.23	0.40		54			5	5	2		692
	Indicated	17,668	1.51		1.13	0.44		46			267	200	78		26,083
	M&I	18,069	1.50		1.13	0.44		46			272	205	80		26,775
	Inferred	11,837	0.69		2.03	0.86		38			82	240	102		14,597
Santo Domingo³ 31-Mar-2024	Measured	134,000	0.51						0.07	26.9	679					293	36
	Indicated	413,000	0.25						0.03	n/a	1,025					449	95
	M&I	547,000	0.31						0.04	n/a	1,704					742	131
	Inferred	230,000	0.21						0.03	n/a	477					200	46
Mantoverde⁴ Sulphides + Mixed (Flotation)	Measured	185,409	0.57						0.10		1,055					596
	Indicated	342,438	0.41						0.10		1,412					1,102
	M&I	527,847	0.47						0.10		2,467					1,698
	Inferred	588,914	0.37						0.08		2,179					1,515
Oxides + Mixed (Dump+Heap Leach) 31-Dec-2023	Measured	239,888		0.21							515
	Indicated	216,110		0.19							401
	M&I	455,998		0.20							915
	Inferred	70,471		0.15							109
Mantos Blancos⁵ Sulphides + Mixed (Flotation)	Measured	92,149	0.73					6			671				18,090
	Indicated	109,940	0.57					4			625				15,236
	M&I	202,089	0.64					5			1,296				33,326
	Inferred	22,450	0.47					3			106				2,350
Oxides + Mixed (Dump Leach) 31-Dec-2023	Measured	22,073		0.34							75
	Indicated	95,672		0.17							167
	M&I	117,745		0.20							242
	Inferred	23,565		0.19							45

Total Measured and Indicated Mineral Resources											10,906	205	80	75	58,783	2,440	131
Total Inferred Mineral Resources											3,407	240	102	9	16,942	1,715	46

NOTES: Mineral Resources take into account mining activities to December 31, 2023, where applicable and are reported insitu, using the 2014 CIM Definition Standards. Mineral Resources that are not Mineral Reserves do not have demonstrated economic viability. Mineral Resources are reported inclusive of the Mineral Reserves. All Mineral Resources are exclusive to dilution and mining recovery factors. All contained metals are reported at 100% except as stated. Rounding as required by reporting guidelines may result in apparent summation differences between tonnes, grade and contained metal content. Grade TCu% refers to total copper grade in percent sent to the mill for metallurgical recovery by flotation. Grade SCu% refers to soluble copper grade in percent sent to the leaching processes. Grade ICu% refers to insoluble copper grade in percent, based on TCu% minus SCu%. Contained ounces (oz) are troy ounces. COG is cut-off grade. NSR is net smelter return. M&I = Measured & Indicated. All amounts in US$ unless otherwise specified. Stockpiled material is treated as Mineral Resources, described below. See Technical Reports filed under Capstone Copper’s profile on SEDAR+ for further information.

¹Garth Kirkham, P.Geo., FGC is the Qualified Person responsible for the Mineral Resource presented in the Pinto Valley Mine Technical Report, effective March 31, 2021. Klaus Triebel, GPG, Chief Resource Modeler at Pinto Valley Mine, oversaw depletion of the of Mineral Resource for mining activities as at December 31, 2023. Mineral Resources are reported at a 0.14% Cu cut-off grade. Economic assumptions for the reasonable prospects pit include: $3.50/lb Cu, $10.00/lb Mo, 84.6% Cu recovery, 8.9% Mo recovery, $1.74/tonne mining costs, $1.13/tonne G&A costs, $0.88/tonne operational support costs, $4.67/tonne milling costs, and pit slopes by rock type. Stockpile material is included as Measured Mineral Resource. Pinto Valley Mine is an open-pit mine with mineral processing by flotation.

²Clay Craig, P.Eng., Director, Mining & Strategic Planning at Capstone Copper is the Qualified Person responsible for the Mineral Resource in the Cozamin Mine Technical Report, effective January 1, 2023, and the depletion of the Mineral resource for mining activities as at December 31, 2023. Mineral resources are reported at a cut-off of NSR US$59/tonne. Metallurgical recoveries used in the NSR formulae are based on mineralization. Metallurgical recoveries vary by domain and NSR formula. Copper-silver dominant zones use the NSR formula: (Cu%*$70.72 + Ag g/t$0.53) * (1-NSR Royalty%). Copper-silver dominant zones use the following metallurgical recoveries: 96.16% Cu and 85.83% Ag. Copper–zinc zones use the NSR formula: (Cu%$69.74 + Ag g/t$0.50 + Zn%*$12.96) * (1-NSR Royalty%). Copper-zinc zones use the following metallurgical recoveries: 94.82% Cu, 83.82% Ag, 66.95% Zn, and 0% Pb. MNFWZ zinc–silver dominant zones use the NSR formula: (Ag g/t$0.35 + Zn%$16.80 + Pb%*$15.11) * (1-NSR Royalty%). Zinc–silver dominant zones use the following metallurgical recoveries: 66.50% Ag, 86.79% Zn, and 92.86% Pb. The NSR formula for MNV zinc zones is (Ag0.241 + Zn15.511 + Pb12.993)(1-NSRRoyalty%) using metallurgical recoveries of 55% Ag, 80% Zn and 80% Pb. The NSR formula for MNV copper-zinc zones is (Cu69.739 + Ag0.498 + Zn12.956)(1-NSRRoyalty%) using metallurgical recoveries of 95% Cu, 85% Ag and 67% Zn. The formulae include consideration of confidential current smelter contract terms, transportation costs and 1-3% net smelter return royalty payments. Metal price assumptions (in US$) used to calculate the NSR for all deposits are: $3.75/lb Cu, US$22.00/oz Ag, US$1.35/lb Zn and US$1.00/lb Pb. An exchange rate of MX$20 per US$1 is assumed. The NSR cut-off is based on operational mining and milling costs plus general and administrative costs. The Mineral Resource Estimate encompasses both the MNFWZ and the MNV. The Mineral Resource was estimated assuming underground mining by longhole stoping and post-pillar cut-and-fill with mineral processing by flotation. Mineral Resource estimates do not account for mining loss and dilution. All metals are reported as contained.

³Peter Amelunxen, P. Eng., Senior Vice President, Technical Services at Capstone Copper is the Qualified Person responsible for the Mineral Resource estimates for the Santo Domingo, Iris, Iris Norte and Estrellita deposits, effective March 31, 2024. Mineral Resources for the Santo Domingo, Iris and Iris Norte deposits are reported using a net smelter return (NSR) cut-off value of US$9.85/t. NSR is calculated using average long-term prices of US$4.10/lb Cu, US$1,600/oz Au, and Fe prices that depend on the expected grade of the Fe concentrate (US$94.75/dmt or $129.77/dmt or $140.26/dmt Fe concentrate). Mineral Resources are constrained by preliminary pit shells derived using a Lerchs–Grossmann algorithm and the following assumptions: pit slopes 36.3°- 47.9°; mining cost is calculated using a function that depends on where the material comes from (Santo Domingo or Iris Norte) and its destination (dumps, plant or stock); processing cost based on Fe concentrate routing code (including G&A costs); processing recovery based in the recovery equations for copper, gold, and iron as detailed above. For the Estrellita deposit,Mineral Resources are reported using an NSR cut-off value of US$9.63/t. NSR is calculated using average long-term prices of US$4.10/lb Cu and US$1,600/oz Au; only copper, and gold were considered in the NSR calculation(iron was excluded). Estrellita Mineral Resources are constrained by preliminary pit shells generated using a Lerchs–Grossmann algorithm and the following assumptions: pit slopes 43º; mining cost of US$1.55/t, processing cost of US$9.46/t (including G&A cost); processing recovery are calculated based in the recovery curves for copper and gold. The average Iron grades for the Project (Total Indicated, Total Measured plus Indicated, and Total Inferred Resources) cannot be calculated because Estrellita does not contain iron resources.

⁴Ronald Turner, MAusIMM (CP), a WSP employee, is the independent Qualified Person responsible for the Mineral Resource in the Mantoverde Mine and Mantoverde Development Project Technical Report effective November 29, 2021. Luis Tapia Hurtado, CP CMC, Resource and Reserve Evaluation Geologist at Mantos Copper, oversaw depletion of the Mineral Resource for mining activities as at December 31, 2023, with Direct Supervision by Guillermo Pareja, P.Geo. Mineral Resources are reported on a 100% basis. The attributable percentage to Mantos Copper Holding SpA is 69.993%. COG varies per zone and recovery process: Flotation: Sulphide: TCu ≥0.20%, Mixed: TCu ≥0.22% and SCu/TCu ≤50%. Dump Leach: Oxide: 0.10%≤SCu<0.17%, Mixed: 0.10%≤SCu<0.17% and SCu/TCu >50%. Heap Leach: Oxide: SCu≥0.17%, Mixed: SCu≥0.17% and SCu/TCu >50%. Flotation recovery is based on a geometallurgical model, 90.8% TCu and 67.9% Au average. Heap Leach recovery is 79.2% average. Dump recovery is based on operating data 37.7%SCu. The Mineral Resource pit is based on US$3.75/lb Cu.

⁵Ronald Turner, MAusIMM (CP), a WSP employee, is the independent Qualified Person responsible for the Mineral Resource in the Mantos Blancos Mine Technical Report effective November 29, 2021. Luis Tapia Hurtado, CP CMC, Resource and Reserve Evaluation Geologist at Mantos Copper, oversaw depletion of the Mineral Resource for mining activities as at December 31, 2023 with Direct Supervision by Guillermo Pareja, P.Geo. Mineral Resources are reported on a 100% basis. The attributable percentage to Mantos Copper Holding SpA is 99.993%. COG varies by metallurgical process: Flotation at 0.22% Insoluble Cu, Dump Leach at 0.10% Soluble Cu. The Mineral Resource pit is based on US$3.75/lb Cu and US$20.00/oz Ag. Flotation recovery is based on a geometallurgical model, 83.4% TCu and 70.7% Ag as average. Dump recovery is based on average operational data at 42.4% SCu. Through the Osisko silver production agreement, Osisko Gold has the right to buy 100% of the silver production in concentrate, less specified deductions, until reaching 19.3 million ounces and subsequently 40% paying 92% of the market price. The stockpile includes 1,239 kt of Indicated Mineral Resource at 0.45% TCu.

Consolidated Estimated Mineral Reserves

Mineral Reserves											Contained Metal
	Category	kt	TCu %	SCu %	Zn %	Pb %	Mo %	Ag g/t	Au g/t	Fe %	Cu kt	Zn kt	Pb kt	Mo kt	Ag koz	Au koz	Fe³ Mt
Pinto Valley¹ 31-Dec-2023	Proven	231,409	0.34				0.007				780			16
	Probable	104,556	0.28				0.006				294			6
	Total	335,966	0.32				0.007				1,073			22
Cozamin² 31-Dec-2023	Proven	–
	Probable	8,892	1.62		0.58	0.33		44			144	51	29		12,526
	Total	8,892	1.62		0.58	0.33		44			144	51	29		12,526
Santo Domingo³ 31-Mar-2024	Proven	130,945	0.52						0.07	27.2	674					291	13
	Probable	305,111	0.25						0.04	26.2	761					346	56
	Total	436,056	0.33						0.05	26.5	1,435					637	68
Mantoverde⁴ Sulphides + Mixed (Flotation)	Proven	172,210	0.62						0.11		1,067					599
	Probable	64,066	0.51						0.11		326					223
	Total	236,276	0.59						0.11		1,392					821
Oxides + Mixed (Dump+Heap Leach) 31-Dec-2023	Proven	145,235		0.23							334
	Probable	55,290		0.20							111
	Total	200,525		0.22							445
Mantos Blancos⁵ Sulphides + Mixed (Flotation)	Proven	60,426	0.74					6			450				11,631
	Probable	50,972	0.54					4			270				7,012
	Total	111,397	0.65					5			720				18,643
Oxides + Mixed (Dump Leach) 31-Dec-2023	Proven	1,756		0.34							6
	Probable	2,199		0.24							5
	Total	3,954		0.28							11
Total Mineral Reserves											5,220	51	29	22	31,169	1,458	68

NOTES: Mineral Reserves take into account mining activities as stated, where applicable. Rounding as required by reporting guidelines may result in apparent summation differences between tonnes, grade and contained metal content. Grade TCu% refers to total copper grade in percent sent to the mill for metallurgical recovery by flotation. Grade SCu% refers to soluble copper grade in percent sent to the leaching processes. Grade ICu% refers to insoluble copper grade in percent, based on TCu% minus SCu%. All Mineral Reserve estimates take into account dilution and mining recovery factors. Contained ounces (oz) are troy ounces. COG is cut-off grade. NSR is net smelter return. All amounts in US$ unless otherwise specified. Stockpiled material is included in the Mineral Reserves, described below. See Technical Reports filed under Capstone Coppers’s profile on SEDAR+ for further information.

¹Clay Craig, P.Eng., Director, Mining & Strategic Planning at Capstone Copper, is the Qualified Person responsible for the Pinto Valley Mineral Reserve estimate as at December 31, 2023. Economic inputs to the block model were $3.00/lb per pound copper, $10.00/lb molybdenum, 86.0% average Cu recovery, 8.5% average Mo recovery, $1.68/tonne average mining costs, $1.13/tonne G&A costs, $0.88/tonne Ops Support costs, $4.67/tonne milling costs, and pit slopes by rock type. The Mineral Reserve is reported 0.19% copper. Stockpiled material is included as Proven Mineral Reserve. Pinto Valley Mine is an open-pit mine with mineral processing by flotation.

²Clay Craig, P.Eng., Director, Mining & Strategic Planning at Capstone Copper, is the Qualified Person for the Cozamin Mine Mineral Reserve as at December 31, 2023. The Mineral Reserve is reported within fully diluted mineable stope shapes generated by the Deswik Mineable Shape Optimiser software. Mining methods include long-hole stoping and cut-and-fill methods. The Mineral Reserve is reported at or above a blended cut-off of US$60.54/t NSR for long-hole stoping and US$65.55/t NSR for cut-and-fill mining. The NSR cut-off is based on operational mining and milling costs plus general and administrative costs. The NSR formulae vary by zone. Three separate NSR formulae are used based on zone mineralization and metallurgical recoveries. Copper-silver dominant zones use the NSR formula: (Cu66.638 + Ag0.484)(1-NSRRoyalty%). MNFWZ zinc-silver zones use the NSR formula: (Ag0.290 + Zn13.723 + Pb13.131)(1-NSRRoyalty%). MNV zincsilver dominant zones use the NSR formula: (Ag0.228 + Zn12.121 + Pb11.363)*(1-NSRRoyalty%). Metal price assumptions of Cu = US$3.55/lb, Ag = US$20.00/oz, Pb = US$0.90/lb, Zn = US$1.15/lb and metal recoveries of 96% Cu, 86% Ag, 0% Pb and 0% Zn in copper-silver dominant zones, 0% Cu, 61% Ag, 93% Pb and 88% Zn in MNFWZ zinc-silver dominant zones, and 0% Cu, 56% Ag, 80% Pb and 77% Zn in MNV zinc-silver dominant zones. The formulae include consideration of confidential current smelter contract terms, transportation costs and 1–3% net smelter return royalty payments. Royalties are dependent on the mining concession, and are treated as costs in the Mineral Reserve estimates. Totals may not sum due to rounding.

³Peter Amelunxen, P. Eng., Senior Vice President, Technical Services at Capstone Copper is the Qualified Person responsible for the Santo Domingo Project Mineral Reserve effective March 31, 2024. 1) Mineral Reserves are reported as constrained within Measured and Indicated Resources and pit designs optimized using the following economic and technical parameters: metal prices of US$3.75/lb Cu, US$1,400/oz Au and Fe prices ranging from US$69/dmt to US$114.51/dmt based on the Fe grade in concentrate (net of Fe concentrate transport costs); average recovery to concentrate is 90.1% for Cu and 56.3% for Au, with magnetite concentrate recovery varying on a block-by-block basis; copper concentrate treatment charges of US$80/dmt, U$0.08/lb of copper refining charges, US$5.0/oz of gold refining charges, US$40/wmt and US$25.75/dmt for shipping copper and iron concentrates respectively; waste and ore mining cost of $1.55/t and process and G&A+SUSEX of US$9.77/t processed; average pit slope angles that range from 36.3° to 47.9°; a 2% royalty rate assumption and an assumption of 100% mining recovery.. No formal production has occurred from the Santo Domingo property area.

⁴Carlos Guzman, RM CMC, FAusIMM, an employee of NCL, is the independent Qualified Person responsible for the Mineral Reserve in the Mantoverde Mine and Mantoverde Development Project Technical Report effective November 29, 2021. Clay Craig, P.Eng., Director, Mining & Strategic Planning at Capstone Copper, oversaw depletion of the Mineral Reserve for mining activities as at December 31, 2023. Mineral Reserves are reported on a 100% basis using average off-site costs (selling cost) of US$0.28/lb for sulphides and US$0.30 for oxides and metal price assumptions (in US$) of Cu = $3.00/lb and Au = $1,100/oz. Mineral Reserves are contained within an optimized pit shell. Mining will use conventional open pit methods and equipment and use a stockpiling strategy (direct mining costs are estimated by geological unit, averaging US$1.85/t of material mined). Processing costs were estimated by geometallurgical units (from UG1 to UG10) averaging US$7.28/t of milled material, including concentrator, tailings storage facility, port and desalination costs. Processing cost for material sent to the heap leach was US$6.28/t. For material sent to the run-of-mine dump leach, the modeled processing cost was US$2.12/t. Total copper recoveries average 88.2% for sulphides and gold recoveries average 71.2%. Soluble copper recoveries average 75.0% for material sent to the heap leach and 42.5% for material sent to the dump leach process. Inter-ramp angles vary from 26˚ to 60˚. The life-of-mine strip ratio is 2.12 to 1.

⁵Carlos Guzman, RM CMC, FAusIMM, an employee of NCL, is the independent Qualified Person responsible for the Mineral Reserve in the Mantoverde Mine and Mantoverde Development Project Technical Report effective November 29, 2021. Clay Craig, P.Eng., Director, Mining & Strategic Planning at Capstone Copper, oversaw depletion of the Mineral Reserve for mining activities as at December 31, 2023. The Mineral Reserve is based on average off-site costs (selling cost) of US$0.27/lb for sulphides and US$0.42/lb for oxides. Mineral Reserves are contained within an optimized pit shell. The estimated Mineral Reserves are reported using metal prices of US$2.90/lb Cu and US$17/oz Ag. Mining will use conventional open pit methods and equipment and a stockpiling strategy (direct mining costs are estimated at the base bench at 900 masl, averaging US$1.60/t of material mined). Processing costs average US$9.98/t of milled material, including concentrator, tailings storage facility and port costs. Processing cost for material sent to dump leach is US$1.47/t. TCu recovery averages 83.1% for sulphides and silver recoveries average 79.5%. SCu recovery averages 42% for material sent to the dump leach. Inter-ramp angles vary from 36˚ to 59˚. The life-of-mine strip ratio is 4 to 1. Through the Osisko silver production agreement, Osisko Gold has the right to buy 100% of the silver production in concentrate (less specified deductions) until reaching 19.3 million ounces and subsequently 40% paying 92% of the market price. Stockpiled material is included in the Probable Mineral Reserve.