• Data Access
  • Your Email  
  • Your Email  
Keep me signed in.
Forgot your password?
Close
  • Forgot Your Password?
  • Enter the email you signed up with and we'll email it to you.
  • Your Email  
Close
Back
MDO
Mining Data Solutions
  • Home
  • Database
  • Subscribe
  • Sign In
  • Sign In
United States
Wharf Mine

This page is not tailored to
devices with screen width under 750 px.
 Location:
16 km S from Spearfish, South Dakota, United States

  Address:
10928 Wharf Road
Lead
South Dakota, United States
57754
Phone  ...  Subscription required
Fax605-584-4188
WebsiteWeb
Additional Resources for Suppliers & Investors
Drill results over 30 g/t Au
Stay on top of recent discoveries.
Search drill results by commodity and grade.
Largest mines in the Americas
Mining and mill throughput capaciites.
Full profiles of select mines and projects.
Deepest underground mines
Shaft depth and mill throughput data.
Full profiles of select mines and projects.
Heavy mobile equipment
HME type, model, size and quantity.
Full profiles of select mines and projects.
Permitting and construction projects
Projects at the permitting or construction stage. Full profiles of select projects.
Mines with remote camps
Camp size, mine location and contacts.
Full profiles of select mines and projects.
Mines & projects in United States
A list of country's mines and projects.
Full profiles of select mines and projects.
  • Overview
  • Owners
  • Geology
  • Mining
  • Processing
  • Production
  • Reserves
  • Costs & Financials
  • Fleet
  • Personnel
  • Filings & News

Thank you for browsing through mine profiles compiled by the Mining Data Online team.

Would you like to subcribe or schedule a Demo?
  • Name:
     
  • Company:
     
  • Position:
     
  • Phone:
  • Email:
  • Message:

Overview

StageProduction
Mine TypeOpen Pit
Commodities
  • Gold
  • Silver
Mining Method
  • Truck & Shovel / Loader
Processing
  • Heap leach
  • Carbon in column (CIC)
  • Elution
  • Carbon adsorption-desorption-recovery (ADR)
  • Solvent Extraction & Electrowinning
  • Cyanide (reagent)
Mine Life7 years (as of Jan 1, 2020)


Owners & OPERATOR

Source: p. 23
CompanyInterestOwnership
Coeur Mining, Inc. 100 % Indirect
Wharf Resources U.S.A. Inc. (operator) 100 % Direct
Coeur acquired the Wharf mine in 2015 and owns all of the issued and outstanding equity interests in Wharf Resources (U.S.A.) Inc.

Deposit Type

  • Epithermal
  • Sediment-hosted


Summary:

The Wharf Operation deposits are considered Tertiary epithermal replacement mineralization, both intrusive-hosted and sediment-hosted (Coeur internal report, 2014). Depth of mineralization at the Wharf Operation (~1.5 km; Paterson and Giebink, 1989) is considered deeper than normal for epithermal deposits, but low temperature of mineralization are consistent with epithermal-type deposits (Paterson, 1990), although these temperatures may represent late stage of fluorite mineralization.

The main trends of mineralization at Wharf parallel the strike of a major joint sets that Shapiro and Gries (1970) measured in upper and lower Deadwood Fm. outcrops. At Golden Reward, the mineralized trends strike north-south. Mineralized trends at Golden Reward may reflect more of an influence from basement structure, as the later faults in the Golden Reward graben area may have been reactivated along faults or moved along existing foliation planes, and mineralization occurred along the same trend as the faulting.

Gold or gold-bearing minerals may be disseminated in porphyry, or may be confined to fractures (Paterson and Giebink, 1989; Paterson, 1990). Highly fractured porphyry is known to be the most mineralized, and preliminary work shows a correlation of fractured porphyry with gold, in contrast to unfractured and unmineralized rocks within mineralized zones. This, however, may be due again to gold-bearing sulfides occurring as the primary economic mineral. Porphyry near fractures is usually the most oxidized, grading outwards into gray, blocky porphyry with very small (< 0.25 mm) grains of disseminated sulfides. Atomic absorption (AA) assaying is limited in determining gold encapsulated in sulfides, but assays of fractured samples that are oxidized will readily measure gold formerly in sulfides. Additional fire assays may help to better understand this association.

Visible native gold observed at Wharf has been only seen twice during current mining activities; one occurrence was found within a fluorite vein. Because fluorite is considered a late-stage mineral (e.g., Paterson et al., 1989), the fluorite-gold occurrence may indicate a later, minor mineralizing event, distinct from earlier, goldbearing sulfide mineralization. Thin sections of very high-grade (1.173 and 0.615 oz/ton Au) samples from the Annie Creek mine analyzed by Schurer and Fuchs (1991) show native gold associated with hematite, goethite, jarosite which forms from oxidation of iron sulfides, and arseniosiderite which forms from oxidation of arsenopyrite; quartz was also associated with gold. A thin section from the lowestgrade sample in this study (0.195 oz/ton Au) showed no native gold, but abundant sulfides, which was assumed to indicate lattice or submicron gold. The discussion suggests that oxidation of arsenic-bearing sulfides may have remobilized gold in an arsenic complex and deposited it as native gold in higher-grade samples (Schurer and Fuchs, 1991).


Mining Methods

  • Truck & Shovel / Loader


Summary:

The Wharf Operation is currently a conventional truck and loader heap leach gold mine. The Wharf Operation consists of five heap leach pads, which are all load/offload pads. The entire planned mining disturbance falls within the current permitted area.

Wharf leases nearly all of the earth moving equipment used at the mine. The current earth moving equipment under lease through local equipment dealers includes: (14) 777 trucks, (1) D-10 and (2) D-9 dozers, (4) 993 front end loaders, (2) 16M motor graders, and (2) DM 45 hammer drills. Relationships with local dealers span over 15 years, and the earthmoving equipment is under contract through 2017.


Crushing and Grinding
Crusher / Mill TypeModelSizePowerQuantity
Jaw crusher ....................... Subscription required 1
Cone crusher ....................... Subscription required 1
Cone crusher ....................... Subscription required 4

Summary:

Ore is trucked to the crusher located at the east end of the plant/pad area to be crushed to a nominal size of 80 percent minus ¾-inch passing. The crushing plant can process between 4.2 and 4.6M tons of ore per year, depending on ore hardness. Lime is added to the crushed ore. Once crushed, the ore is trucked to leach pads to be stacked in 20-foot-high lifts.

Crushing
A single crushing circuit is used to process ore before being transferred to the leach pads. This crushing circuit has undergone numerous modifications over its history to accommodate operational conditions and optimize performance.

Ore is hauled from the pit with CAT 777 and 785 haul trucks that dump directly into a hopper or onto a stockpile adjacent to the hopper. Stockpiled ore is fed into the hopper by a loader at times when a direct ore haul is not available.

Ore is transferred by an apron chain feeder to a vibrating grizzly where oversize rock is diverted in to a Nordberg C140 jaw crusher. The jaw crusher reduces the rock down to a 6-inch nominal size before dropping onto a conveyor belt along with the fines from the grizzly. Powdered lime is added to the ore from a silo as it is conveyed up to the secondary crushing stage. The lime application rate can be adjusted as needed to control solution pH during leaching.

Before being fed into the secondary crusher, the ore passes over a screen deck to remove final product sized material. These fines are conveyed to the final product pile and oversize rock drops into a Nordberg HP 500 cone crusher where it is reduced to 2 ½ inch nominal size. Crushed ore is then conveyed to an adjacent screen plant to remove product size material before being conveyed to the tertiary crushing stage.

The tertiary stage of the crushing system consists of four Nordberg Omnicone 1560 cone crushers. Ore enters the tertiary stage through a diverter that distributes the rock to the four cone crushers. Each cone has its own screen deck to remove product size material before dropping into the crusher. This product size material is conveyed to the final product pile. Rock that is larger than product size falls in the tertiary cones and is crushed down to ¾-inch nominal size. The total crushing system throughput of 750 to 1,000 tons per hour can be achieved with only three of the tertiary cones operating. A fourth cone can be left in standby in the event of a failure or planned maintenance on one of the other cones.

After leaving the tertiary crushers the ore is conveyed back to the screen plant and any material not meeting the final product size is recirculated back into the tertiary cones until it meets specifications. The final product size target is 90 percent passing ¾-inch and 80 percent passing ½-inch.


Processing

  • Heap leach
  • Carbon in column (CIC)
  • Elution
  • Carbon adsorption-desorption-recovery (ADR)
  • Solvent Extraction & Electrowinning
  • Cyanide (reagent)

Flow Sheet: Subscription required

Summary:

Stacked ore is then leached with dilute sodium cyanide solution. Gold and silver in the pregnant (metal-bearing) leach solution (PLS) are recovered by adsorption on activated carbon and the barren (non-metal bearing) leach solution is recycled to the heap leach pad. Spent ore is rinsed, neutralized and denitrified and then removed from the leach pad to be placed on a designated spent ore storage area.

Gold and silver is recovered from loaded carbon utilizing a modified pressure Zadra method. The rich electrolyte (RE) from the elution process is then processed by electrowinning, depositing the metals into an electrolytic sludge with 90-98% gold and silver. Precious metals in the electrolytic sludge are further purified by smelting at a commercial refinery.

Heap Leach
There are currently five on/off heap leach pads used for the leaching cycle; the newest pad (Pad #5) was constructed in 2008. In 2013, Wharf received certification by the International Cyanide Man ........

Recoveries & Grades:

CommodityParameter20192018201720162015
Gold Head Grade, oz/ton 0.020.020.030.030.03
Gold Recovery Rate, %  ......  Subscription required  ......  Subscription required
Subscription required - Subscription is required.

Production:

CommodityUnits2020201920182017201620152014
Gold koz  ......  Subscription required ^  ......  Subscription required77951097872
Silver oz  ......  Subscription required  ......  Subscription required  ......  Subscription required  ......  Subscription required  ......  Subscription required
Gold Equivalent oz  ......  Subscription required  ......  Subscription required  ......  Subscription required  ......  Subscription required
All production numbers are expressed as metal in doré. ^ Guidance / Forecast.
Subscription required - Subscription is required.

Operational Metrics:

Metrics201920182017201620152014
Tonnes milled  ......  Subscription required4,923,774 tons4,560,441 tons4,268,105 tons3,600,279 tons4,201,362 tons
Ore tonnes mined  ......  Subscription required4,190,362 tons
Subscription required - Subscription is required.

Reserves at December 31, 2018:

CategoryTonnage CommodityGradeContained Metal
Proven 34,043,000 tons Gold 0.026 oz/ton 877,000 oz
Probable 153,000 tons Gold 0.033 oz/ton 5,000 oz
Proven & Probable 34,196,000 tons Gold 0.026 oz/ton 882,000 oz
Measured 8,070,000 tons Gold 0.034 oz/ton 271,000 oz
Indicated 626,000 tons Gold 0.042 oz/ton 26,000 oz
Measured & Indicated 8,696,000 tons Gold 0.034 oz/ton 297,000 oz
Inferred 2,553,000 tons Gold 0.026 oz/ton 66,000 oz

Commodity Production Costs:

CommodityUnits20192018201720162015
Total cash costs (sold) Gold Equivalent USD 880 / oz 697 / oz 606 / oz 706 / oz
Total cash costs (sold) Gold USD  ......  Subscription required† 879 / oz† 693 / oz†
† Net of By-Product.
Subscription required - Subscription is required.

Financials:

Units20192018201720162015
Capital expenditures M USD  ......  Subscription required3.38  8.84   4.81   3.21  
Sustaining costs M USD 5.8   4.8   3.2  
Revenue M USD  ......  Subscription required96.5  125.9   136.68   84.1  
After-tax Income M USD  ......  Subscription required13.5  37   43.1   12.9  
Operating Cash Flow M USD 49.6   62.4   32  
Subscription required - Subscription is required


Heavy Mobile Equipment as of February 7, 2018:
HME TypeModelQuantityLeased or
Contractor
Dozer ....................... Subscription required 1
Dozer ....................... Subscription required 4
Dozer ....................... Subscription required 1 Leased
Drill ....................... Subscription required 2
Drill ....................... Subscription required 1
Drill ....................... Subscription required 2 Leased
Grader ....................... Subscription required 2 Leased
Loader (FEL) ....................... Subscription required 4 Leased
Truck (haul) ....................... Subscription required 4 Leased
Truck (haul) ....................... Subscription required 10 Leased
Subscription required - Subscription is required.

Mine Management:

Job TitleNameProfileRef. Date
....................... Subscription required ....................... Subscription required Subscription required Mar 15, 2021
....................... Subscription required ....................... Subscription required Subscription required Mar 15, 2021
....................... Subscription required ....................... Subscription required Subscription required Mar 15, 2021
....................... Subscription required ....................... Subscription required Subscription required Mar 15, 2021
Subscription required - Subscription is required.

Staff:

EmployeesYear
Subscription required 2020
Subscription required 2019
Subscription required 2018
Subscription required 2017
Subscription required 2016
Subscription required 2015

Corporate Filings & Presentations:

DocumentYear
................................... Subscription required 2021
................................... Subscription required 2020
................................... Subscription required 2020
................................... Subscription required 2020
................................... Subscription required 2019
................................... Subscription required 2019
................................... Subscription required 2019
................................... Subscription required 2019
Form 10-K 2018
Press Release 2018
Technical Report 2018
Year-end Mineral Reserves 2018
Annual Report 2017
Year-end Mineral Reserves 2017
Annual Report 2016
Press Release 2016
Press Release 2016
Year-end Mineral Reserves 2016
Annual Report 2015
Technical Report 2015
Year-end Mineral Reserves 2015
Subscription required - Subscription is required.

Aerial view:

Subscription required - Subscription is required.

Terms of Use Privacy Policy © 2020 MDO Data Online Inc.