Overview

Mine Type	Underground
Stage	Preliminary Economic Assessment
Commodities	Copper Silver
Mining Method	Room-and-pillar
Mine Life	...

Deposit type

• Sediment-hosted

Summary:

The mineralization of the White Pine North Project is classified as a reduced facies stratiform sediment-hosted copper deposit.

Copper mineralization at the White Pine deposit occurs in two modes - as very fine-grained sulfide (chalcocite) and as native copper. Sulfide mineralization is estimated to account for 85-90% of the copper in the deposit, but both modes of copper are intimately associated throughout the deposit. The copper mineralization at White Pine is unusually consistent. All drill holes within the deposit intercepted mineralized strata. Within the deposit, the grades of the mineralization are usually above cut-off grade over normal mining configurations. Most of the beds in the mineralized horizon are continuous over the entire deposit. The beds comprising the Parting Shale pinch out in the southwest part of the historic mine. The variation of the thickness of mineralized beds is also low from drill hole to drill hole.

Sulfide Mineralization: The dominant copper mineral in the White Pine deposit is chalcocite (Cu2S). It occurs as fine-grained lamellae in laminites and partings in interbedded sandstone and shale, very-fine grained disseminations and discrete clots in siltstone, and in veinlets and veins. The top of the copper mineralization is identified as the Top of Mineralization (“TOM”) Line or “fringe,” a narrow transition zone between cupriferous and pyritic zones. The fringe is typically very narrow (a few inches) and is identified by the sequence: chalcocite, digenite, bornite, chalcopyrite, and pyrite. Immediately above the cupriferous zone is a narrow zone containing disseminated greenockite, galena, and wurtzite. The yellow color of greenockite is easily spotted in drill core. The TOM Line cross-cuts stratigraphy. In the shallow areas of the mine to the west near the portal, the TOM Line is typically 9.5 m (30 ft) above the Lower Sand while to the east the TOM Line descends through the otherwise normally mineralized beds.

Native Copper: Native copper mineralization occurs throughout the deposit. The most significant occurrences are as sheet copper and mineralized sandstone. Sheet copper forms along thrust surfaces in the southwest mine. The sheet copper in thrust surfaces is bedding parallel as well as cross-cutting stratigraphy. Sheets can reach spectacular size. It was observed that some sheets could be traced through entire pillars. Mineralized sandstone occurs in the uppermost part of the Copper Harbor Conglomerate and is invariably associated with trapped hydrocarbons. The greatest amounts of mineralized sandstone were found in areas adjacent to the White Pine fault.

Mixed Sulfide and Native Copper Mineralization: Native copper and chalcocite are found throughout the deposit. Native copper is found in close relationship to copper sulfide in sandy lenses and pods (load casts) in the Lower Transition. Native copper in the Lower Transition is more common in channels incised into the top of the CHC. Both chalcocite and native copper mineralization are ubiquitous features of the mineralization of the Dark Gray Massive bed as well; chalcocite occurs as very-fine grained disseminations; and native copper, as discrete blebs.

Structural Relationship: Structure imposes a significant control on the distribution and grade of mineralization. Higher-grade ore is spatially associated with the White Pine fault and thrust and strike-slip faults in the Southwest mine. Part of the increase in grade is due to the presence of mineralized sandstone and/or sheet copper. In addition, chalcocite mineralization is also enhanced as wider lamellae and crosscutting veins and veinlets in the laminites.

Formation Water: The formation water encountered in the CHC is an alkaline brine with a chloride and TDS content approximately twice that of seawater. These compositions are thought to represent an approximate original composition of the depositional lake water and ore bearing fluid. Further support for alkaline brines existing during Nonesuch times is the abundance of carbonate throughout the CHC and Nonesuch Formation.

Hydrocarbons: The White Pine Mine is famous for its hydrocarbon seeps. In many areas near the White Pine fault, hydrocarbons seep out of the back, drip, and form puddles of “oil” on the floor. The most prolific seeps were noted in the northwest portion of the mine near and beneath the North Number One tailings dam.

Mining Methods

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Comminution

Crushers and Mills

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Processing

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Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		Feb 22, 2024
.......................	.......................		Nov 6, 2019
.......................	.......................		Nov 6, 2019
.......................	.......................		Nov 8, 2023
.......................	.......................		Nov 8, 2023

Total Workforce	Year
......	2019