Summary

Mine Type	Open Pit
Status	Active
Commodities	Copper Molybdenum Silver
Mining Method	Truck & Shovel / Loader
Production Start	...
Mine Life	...
Snapshot	The Montana Resources operation comprises the Continental mine, crushers and a concentrator facility where tons of raw ore are processed into high-quality metal concentrates. Montana Resources, Inc. is a private company. Public records for Continental Mine production data are not available.

Deposit type

• Porphyry
• Vein / narrow vein

Summary:

In the Continental area, Butte Quartz Monzonite is host to low-grade, porphyry style, copper and molybdenum mineralization exposed at surface in the footwall of the Continental Fault. This style of mineralization was intercepted by underground workings beneath the Berkeley pit at about the 2,000 level. Subparallel strands of the Continental Fault, collectively thought to have as much as 3,500 feet of dip-slip displacement, are exposed, along strike, in the bottom reaches of the Continental pit and in “cross section” in the north highwall. The deposit is bounded on the west by the Continental Fault and on the East by the Klepper Fault. In the Butte District, two mineralizing events are recognized as important relative to reserve definition: PreMain Stage (PMS) and Main Stage (MS).

The Pre-Main Stage veinlet swarms and crackles with distinctive secondary green biotitic selvages, typify the potassium feldspar metasomatism associated with the early quartz-chalcopyrite-molybdenite porphyry style mineralization. Swarms of barren quartz, molybdenite crackles (slicks), and various styles of banded quartzmolybdenite veinlets marked the end of the Pre-Main Stage event and set the structural pattern for the classic mesothermal Main Stage veining to follow. These east to northeasterly trending, steeply dipping, massive copper sulfide veins, characterized by wide sericitic envelopes, often offset by conjugate northwest trending MS veins with gouge in both the hanging wall and footwall, sustained the historic underground mining in Butte, but occur only as small veinlets in the Continental pit.

The bulk of the Continental orebody that sustains ongoing mining was mineralized by interlacing Pre-Main Stage crackles and veinlet swarms. Deepening of the current pit continues to exploit this mineralization. Ongoing research over the past 30 years, however, has further quantified another facet of Butte geology that is important to reserve definition. As a result of deep drilling in the District, a massive quartz-sericite-pyrite plug was delineated at depth in the southeast corner of the Berkeley pit that was contemporaneous with MS mineralization. It is thought that fluids from this intrusive mixed with meteoric water and sericitized a massive area above the PMS porphyry system.

The swarms of pyrite and quartzpyrite veinlets associated with this intervening mineralization prepared the ground for subsequent supergene copper enrichment that occurred with ongoing weathering as the district was uplifted and faulted by the mountain building processes along the Rocky Mountain Front. These events produced the copper enrichment blankets conformable with ancient ground water tables both east and west of the current Continental pit.

Mining Methods

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Comminution

Crushers and Mills

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Processing

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Commodity Production

Commodity	Units	2022	2021	2020	2019	2016	2015
Copper	M lbs	....	....	....	65 *	69 *	70 *
Molybdenum	M lbs	....	....	....	9 *	9.5 *	8 *
Silver	koz	....	....	....		600 *

Operational metrics

Personnel

Job Title	Name	Phone	Profile	Ref. Date
.......................	.......................	...........		Oct 28, 2024
.......................	.......................			Oct 28, 2024
.......................	.......................			Oct 28, 2024
.......................	.......................	...........		Jul 25, 2023
.......................	.......................			Oct 28, 2024

Total Workforce	Year
......	2023
......	2022
......	2021
......	2020
......	2019
......	2018
......	2015