Overview
Stage | Production |
Mine Type | Open Pit |
Commodities |
- Copper
- Molybdenum
- Silver
- Gold
|
Mining Method |
|
Processing |
- Flotation
- ROM/dump leach
- Solvent Extraction & Electrowinning
|
Mine Life | 13 years (as of Jan 1, 2016) |
Latest News | Capstone Beats 2020 Production and Cost Guidance February 24, 2021 |
Source:
p. 6
Company | Interest | Ownership |
Capstone Mining Corp.
|
100 %
|
Indirect
|
Pinto Valley Mining Corp.
(operator)
|
100 %
|
Direct
|
Source:
p.24
Summary:
The primary sulphide minerals encountered at the Pinto Valley Mine are chiefly pyrite and chalcopyrite with minor amounts of molybdenite. Gold and silver are recovered as by-products. Sphalerite and galena occur locally in very small amounts. Alteration of silicate minerals of the host rocks to other groups of minerals due to the presence of hydrothermal fluids associated with the Cu-Mo-bearing intrusive rocks include potassic, argillic, sericitic, and propylitic alteration suites.
Sulphide minerals generally occur in veins and microfractures and less abundantly as disseminated grains, predominantly in biotite sites. The ore zone grades outward into a pyritic zone with higher total sulphide content. Molybdenum distribution generally reflects copper distribution, with higher molybdenum values usually found in the higher grade copper zones. Oxide mineralization and a supergene enrichment blanket was developed at the Pinto Valley Mine, but these areas have since been mined.
Sulphide deposition at Pinto Valley is controlled to some extent by the host rock. The sulphide content decreases in Precambrian aplite intrusions. Aplite usually contains less than 0.25% copper, whereas adjacent Quartz Monzonite may have as much as 0.6% copper. The deficiency of copper in aplite is probably due to the absence of biotite, which makes up about 7% of Quartz Monzonite. Disseminated chalcopyrite shows an affinity for biotite, where it is disseminated through the biotite or partially replacing it. Additional chalcopyrite is also present in veins cutting both rock types.
Source:
p.18
Summary:
Pinto Valley copper mine is an open-pit mine with conventional processing facilities and an SX/EW plant for low-grade copper extraction. The Pinto Valley Mine, which restarted in December 2012, uses a conventional drill and blast, and truck and shovel fleet. The pit is mined in 14 m benches with a double bench configuration in deeper zones.
Source:
p.157-158
Crusher / Mill Type | Model | Size | Power | Quantity |
Gyratory crusher
|
|
60" x 89"
|
|
1
|
Cone crusher
|
Metso Nordberg
|
7'
|
|
9
|
Ball mill
|
Allis-Chalmers
|
18' x 21'
|
4000 HP
|
6
|
Regrind
|
|
11' x 15'
|
|
2
|
Summary:
ROM ore is delivered by haul truck to a Fuller Traylor™ 60 inch × 89 inch gyratory primary crusher. The trucks discharge directly into the crusher, which is set in a dump pocket. The crushed ore is withdrawn from a surge pocket under the crusher by an apron feeder, which discharges onto the primary conveyor. The primary conveyor transports the primary crushed ore to the coarse ore stockpile, which has a nominal live capacity of 30,000 tons. Based on digital size analysis of the primary crusher discharge, the P80 of the primary crushed ore is approximately 3.5 inches. The fine product distribution is attributed to ore fragmentation and mine blasting practices. The discharge product averages 66% -2 inch and 45% -1 inch.The amount of fines in the feed has a significant influence on the production capacity of the fine-crushing facility.
The coarse ore is reclaimed from the coarse ore stockpile bysix apron feeders, which feed three coarse ore reclaim belts. Each coarse ore reclaim belt discharges onto a 7ft × 16ft Simplicity™ double-deck vibrating screen. Each screen oversize feeds a secondary 7ft Nordberg™ standard cone crusher. Screen undersize from the secondary screens is sent to the FOB, with a nominal live capacity of 44,000tons.
The secondary crushers operate in open circuit. Crusher product from all three secondary crushers is forwarded via a common conveyor system to the tertiary crusher feed bin. Ore is withdrawn from the tertiary crusher feed bin by six feeders and delivered directly to six 8ft × 20ft Simplicity™ double-deck vibrating screens. The screen undersize from the tertiary screens is sent via a common conveyor system to the Fine Ore Bin (FOB). The screen oversize is crushed by six 7ft Nordberg™ tertiary shorthead cone crushers. The product from the six shorthead crushers is added to the secondary crusher product on the common conveyor system to feed the tertiary feed bin, so that tertiary crushing is in closed circuit. At the current plant throughput, the P80 of the fine-crushing plant is about 11 mm.
Grinding
Fine ore is reclaimed from the FOB and fed directly to six 18ft × 21 ft, 4,000hp Allis-Chalmers™ overflow ball mills. Each ball mill is an independent circuit consisting of discharge sump, pump, and cyclone cluster. Water is added to the ball mill feed to achieve the desired percent solids content for grinding.Additional water is required at the ball milldischarge sump to maintainthe optimal operation of the cyclones. Each circuit is equipped with three 33-inch inclined cyclones. Cyclone overflow slurry gravity feeds the rougher flotation banks, while the underflow discharges back to the ball mill feed sump. The ball mills operate in closed circuit with the cyclones, with a circulating load estimated at 300%. Xanthate, dithiophosphate, diesel, and lime are added to the grinding circuit to prepare the ore in the slurry for flotation.
Regrind
The rougher concentrate is delivered to the regrind ball mill circuit. Rougher concentrate is combined with the regrind ball mill discharge and pumped to the closed-circuit cyclones. The target product for regrind cyclone overflow is P80 of 50 µm.
Processing
- Flotation
- ROM/dump leach
- Solvent Extraction & Electrowinning
Flow Sheet:
Summary:
The processing facility consists of three crushing stages, ball mills, copper flotation stages, a molybdenum flotation circuit, and associated thickeners for concentrates and tailings. Two previous tailings dams have been rehabilitated and two tailings dams are currently operational. Pinto Valley also has an SX/EW facility that processes pregnant leach solution from low copper grade material that is leached. The SX/EW accounts for less than 5% of production.
Flotation
The flotation circuit operates as a staged process designed for the recovery of copper and molybdenum to individual concentrates. The primary focus of the rougher flotation circuit is to optimize recovery of the primary sulfide minerals from the gangue into a reduced mass for economic downstream processing. Cleaner flotation delivers economic concentrate grades for marketing while maintaining high recoveries.The flotation reagents used include Flomin™ C-3430 (Xanthate), C-2420 (dithiophosphate), and F-171 (frother). Some of the flotation reagents have been added to the grinding circuit for slurry conditioning, with addition rates augmented in the flotation circuit where required.Regrinding of the rougher concentrate is required to provide the further mineral liberation to allow high concentrate grades and recoveries from the cleaners. The molybdenum in the PVM ore is recovered to the bulk cleaner concentrate with the copper. The molybdenum flotation circuit provides the separation of the copper and molybdenum into respective concentrates for marketing.
Rougher Flotation
The rougher flotation circuit consists of sixty-five 1,000 ft3Wemco™ cells configured in three trains, with cyclone overflow from two ball mills feeding each train. Frother is added to the head of the rougher flotation cells, with other reagents (that were added at grinding) added as required. The rougher section is operated in open circuit, with the rougher tailings going directly to the final tailings.
Cleaner Flotation
The cleaner circuit consists of four 8 ft diameter × 40 ft tall column flotation cells operated inparallel. The column cell concentrate, the final copper-molybdenum bulk concentrate, contains 27%–29% Cu and 0.35%–0.7% Mo. The column cell tails are sent to the cleaner scavenger flotation bank. The cleaner Pinto Valley Mine Life Extension Study, February 2016Page | 159scavenger bank comprises fifteen 300 ft3Wemco™ flotation cells. The concentrate from the first five cells is recirculated to the column cells. The concentrate from cells 6 to 15 is recirculated to the head of the cleaner scavenger bank. The tails of the cleaner scavenger bank are sent to final tailings.
Molybdenum Plant
The copper-molybdenum concentrate from the cleaner columns is thickened before being sent to the molybdenum plant. The plant comprises four banks of Agitair™ rougher cells of six 50 ft 3 cells each and three stages of cleaning using column cells. Sodium hydrosulfide is added to the slurry to provide depression of copper and iron sulfides. Fuel oil is added as a molybdenum promoter.
SX-EW
The PVM SX-EW plant was built and commissioned in 1981 to process solutions from the leach grade material placed on the leach dumps north of the pit. Through 1998, approximately 450 M tonnes of 0.13% T Cu material had been placed on the leach, resulting in production of 10 to 15 M lbs of cathode copper per year in the early 2000s. Over the last few years, the SX-EW has produced in the range of 5 to 8 M lbs of cathode per year due to the declining residual copper inventory in the leach piles. The PV3 plan utilizes the leach area and pregnant solution pond as waste rock storage, resulting in leaching operations being discontinued at the end of 2018.
Recoveries & Grades:
Commodity | Parameter | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 |
Copper
|
Recovery Rate, %
| 85.1 | 84.6 | 89.2 | 86.7 | 87.4 | 88.9 |
Copper
|
Head Grade, %
| 0.33 | 0.32 | 0.32 | 0.37 | 0.38 | 0.41 |
Copper
|
Concentrate Grade, %
| 26.3 | 26 | 28.2 | 28.5 | 28.6 | 29.6 |
Molybdenum
|
Head Grade, %
| | 0.01 | 0.01 | 0.01 | 0.01 | 0.01 |
Production:
Commodity | Product | Units | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 |
Copper
|
Payable metal
|
M lbs
| 114 | 115 | 122 | | | |
Copper
|
Metal in concentrate
|
M lbs
| 118 | 119 | 126 | 147 | 133 | 144 |
Copper
|
Concentrate
|
dmt
| 196,560 | 201,747 | 196,583 | 234,702 | 203,966 | 211,709 |
Molybdenum
|
Concentrate
|
dmt
| 75 | 148 | 64 | 174 | 184 | 344 |
Molybdenum
|
Metal in concentrate
|
M lbs
| | 0.2 | 0.1 | 0.2 | 0.2 | 0.2 |
Silver
|
Metal in concentrate
|
koz
| | 324 | 316 | 377 | 290 | 286 |
Gold
|
Metal in concentrate
|
oz
| | 1,717 | 3,687 | 1,944 | 1,002 | 923 |
Operational Metrics:
Metrics | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 |
Total tonnes mined
| 48,989 kt | 46,977 kt | 46,770 kt | 42,942 kt | 34,603 kt | 21,863 kt |
Ore tonnes mined
| 18,888 kt | 19,290 kt | 20,605 kt | 23,435 kt | 23,139 kt | 20,931 kt |
Waste
| 30,101 kt | 27,687 kt | 26,165 kt | 19,507 kt | 11,464 kt | 932 kt |
Tonnes milled
| 18,665 kt | 19,246 kt | 19,655 kt | 20,565 kt | 17,730 kt | 17,231 kt |
Daily milling rate
| 51,137 t | 52,728 t | 53,849 t | 56,189 t | 48,576 t | 47,209 t |
Reserves at December 31, 2018:
Category | Tonnage | Commodity | Grade | Contained Metal |
Proven
|
255 Mt
|
Copper
|
0.33 %
|
0.84 Mt
|
Proven
|
255 Mt
|
Molybdenum
|
0.006 %
|
0.016 Mt
|
Probable
|
153 Mt
|
Copper
|
0.28 %
|
0.43 Mt
|
Probable
|
153 Mt
|
Molybdenum
|
0.006 %
|
0.009 Mt
|
Proven & Probable
|
408 Mt
|
Copper
|
0.31 %
|
1.27 Mt
|
Proven & Probable
|
408 Mt
|
Molybdenum
|
0.006 %
|
0.025 Mt
|
Measured
|
571 Mt
|
Copper
|
0.33 %
|
1.88 Mt
|
Measured
|
571 Mt
|
Molybdenum
|
0.006 %
|
0.034 Mt
|
Indicated
|
759 Mt
|
Copper
|
0.27 %
|
2.07 Mt
|
Indicated
|
759 Mt
|
Molybdenum
|
0.005 %
|
0.039 Mt
|
Measured & Indicated
|
1,330 Mt
|
Copper
|
0.3 %
|
3.95 Mt
|
Measured & Indicated
|
1,330 Mt
|
Molybdenum
|
0.005 %
|
0.073 Mt
|
Inferred
|
146 Mt
|
Copper
|
0.24 %
|
0.34 Mt
|
Inferred
|
146 Mt
|
Molybdenum
|
0.005 %
|
0.008 Mt
|
Commodity Production Costs:
| Commodity | Units | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 |
Credits (by-product)
|
Copper
|
USD
|
-0.09 / lb
|
-0.06 / lb
|
-0.08 / lb
|
-0.06 / lb
|
-0.05 / lb
|
-0.06 / lb
|
-0.05 / lb
|
All-in sustaining costs (AISC)
|
Copper
|
USD
|
2.48 / lb†
|
2.7 / lb†
|
2.31 / lb†
|
1.94 / lb†
|
2.26 / lb†
|
|
|
C1 cash costs
|
Copper
|
USD
|
2.05 / lb†
|
2.16 / lb†
|
1.95 / lb†
|
1.61 / lb†
|
1.97 / lb†
|
2.03 / lb†
|
2.26 / lb†
|
All-in costs
|
Copper
|
USD
|
|
|
2.34 / lb†
|
1.95 / lb†
|
2.68 / lb†
|
|
|
† Net of By-Product.
Operating Costs:
| Units | 2019 | 2018 |
Total operating costs ($/t milled)
|
USD
| 10 | 10.2 |
Financials:
| Units | 2019 | 2018 | 2017 | 2016 | 2015 | 2014 | 2013 |
Capital expenditures
|
M USD
| 55.9 | 60.9 | 48 | 22.6 |
68.3
|
40.1
|
|
Revenue
|
M USD
| 300.31 | 294.71 | 322.03 | 302.54 |
260.56
|
377.97
|
86.3
|
Operating Income
|
M USD
| 8.01 | 35.3 | 64.6 | 45.3 |
-21.82
|
78.9
|
5.45
|
After-tax Income
|
M USD
| 5.25 | 16 | 55.3 | 36.5 |
-6.29
|
51.6
|
3.22
|
EBIT
|
M USD
| 3.48 | 32.8 | 60.6 | 42.4 |
-26.24
|
73.3
|
4.47
|
Heavy Mobile Equipment as of January 18, 2016:
Source:
p.3
HME Type | Model | Quantity | Status |
Drill
|
|
3
|
Existing
|
Loader
|
Caterpillar 994
|
2
|
Existing
|
Shovel (hydraulic)
|
|
2
|
Existing
|
Truck (haul)
|
Caterpillar 789
|
18
|
Existing
|
Truck (haul)
|
Caterpillar 789
|
2
|
Proposed
|
Mine Management:
Job Title | Name | Profile | Ref. Date |
Chief Geologist
|
Klaus Triebel
|
|
Feb 26, 2021
|
General Manager
|
Mike Wickersham
|
|
Feb 26, 2021
|
Maintenance Planner
|
Larry Kotopoulous
|
|
Feb 26, 2021
|
Maintenance Superintendent
|
Chance Fuller
|
|
Feb 26, 2021
|
Metallurgical Superintendent
|
Umut Erol
|
|
Feb 26, 2021
|
Mine Manager
|
Rodrigo Huerta
|
|
Feb 26, 2021
|
Mine Operations Superintendent
|
Tucker Jensen
|
|
Feb 26, 2021
|
Mine Superintendent
|
Mike Buck
|
|
Feb 26, 2021
|
Mining Manager
|
Clay Craig
|
|
Feb 26, 2021
|
Operations Support Manager
|
Colleen Roche
|
|
Feb 26, 2021
|
Operations Support Superintendent
|
Dennis Palmer
|
|
Feb 26, 2021
|
Process Manager
|
Bob Dickey
|
|
Feb 26, 2021
|
Staff:
Total Workforce | Year |
638
|
2017
|
607
|
2016
|
Corporate Filings & Presentations:
News: