The Craigmont past-producing mine is located on an east-facing slope, west of Guichon Creek and approximately 14.5 kilometres northwest of the community of Merritt.

The Promontory Hills area is underlain by a complex east-northeast–trending, steeply dipping volcanic pile of Upper Triassic Nicola Group rocks, bounded to the north by the multistage Early Jurassic to Late Triassic Guichon Creek Batholith and unconformably overlain by the Middle and Upper Cretaceous Spences Bridge Group. Most of the area is covered by extensive gravel overburden.

In the vicinity of the Craigmont mine, the Border phase of the Guichon Creek Batholith varies in composition from quartz diorite to granodiorite. These rocks intrude the Nicola Group, a thick volcanic and sedimentary series of agglomerate, breccia, andesitic flows, limestone, argillite and greywacke. Attitudes parallel the intrusive contact zone. Sediments immediately adjacent to the batholith are hornfelsed quartzofeldspathic greywackes. Spences Bridge Group agglomerates and flows dip approximately 15 degrees to the south and outcrop in the areas south and west of the mine.

The Craigmont mine lies adjacent to the southern margin of the Guichon Creek Batholith. Host rocks to the mineralization are calcareous sedimentary rocks of the Nicola Group comprised of limestones, limy tuffs, greywackes and argillites.

The gross structure at the mine is a large anticline with ore-bearing drag folds on the north limb. These folds plunge 60 to 70 degrees eastward and are often occupied by diorite dikes. The anticline is cut off by a northwest-trending fault on the west and an east-trending fault on the south. Orebodies lie within a block bounded by these regional faults and the Guichon Creek intrusive.

Alteration mineralogy indicates thermal zoning. Within the hornfelsed zone, greywackes contain biotite and actinolite and limestone is altered to marble. Immediately to the south is a massive actinolite skarn that is further altered to epidote and garnet (grossularite, andradite) in places.

Three types of alteration are present. First is a zone of potassic alteration with a related (second) distal hornfels. Third is skarn alteration that overprints the potassic alteration and some of the hornfels. The skarn is garnet-epidote-amphibolite in composition with some chlorite, tourmaline and sericite.

Mineralization consists of magnetite, hematite and chalcopyrite and occurs as massive pods, lenses and disseminations extending through the calc-silicate horizon. The body is roughly tabular, trends east and dips near vertically. Minor folding and faulting is present but does not significantly distort the mineralization. Chalcopyrite is associated with, but postdates, the magnetite and commonly encloses the magnetite.

Chalcopyrite is the principal ore mineral and occurs as veins, streaks, patches and coarse disseminations. It was first deposited with magnetite during the development of the actinolite skarn and later with specularite as fracture fillings and veins. Bornite is present in small amounts. Pyrite is confined to areas of heavy garnet alteration. Approximately 20 per cent of the ore (by weight) is magnetite and hematite, which occurs in the skarn along with actinolite, epidote, grossularite, andradite, pyrite and minor diopside. Supergene minerals, native copper and chalcocite, occur in a narrow, oxidized zone immediately above the orebody. The apparent ore controls are favourable hostrock, folding and brecciation of hostrock, and proximity to the batholith.

Semicontinuous ore is found over a strike length of 900 metres and a vertical depth of 600 metres. The five main orebodies are confined to the limy horizon between walls of greywacke and andesite. The No. 1 and 2 zones are believed to have been mined out; historical reports suggest the No. 3 and 4 zone remain open for exploration.

The No. 3 zone is an east-plunging elongate body underlying No. 1 and 2 zones. The No. 3 zone is not believed to have been mined when the Craigmont mill was originally optimized to handle coarser grained, low-sulphide chalcopyrite-magnetite minerals. Using a 0.7-per cent cut-off and a 6-metre mining width, Bristow (1985) calculated a possible (non-NI 43-101 compliant) reserve of 1 170 000 tonnes grading 1.53 per cent copper (Cuttle, J. (2013-05-07): Technical Report on the Thule Copper-Iron Property). The No. 3 zone remains open to the east and west.

Recent (2019) diamond drilling targeted deeper sections below and west of the open pit to test the No. 3 orebody and intersected two distinct zones of mineralization, referred to as the Upper zone and the No. 3 zone. The Upper zone is associated with a weakly developed fracture network of chalcopyrite mineralization associated with chlorite in intermediate argillic- to propylitic-altered hostrock with some quartz–potassium feldspar veinlets. The zone appears to widen to the east and is associated with stronger potassium feldspar flooding and better developed fracture networks. The No. 3 zone is described as being similar to the Upper zone but comprises only intermediate argillic alteration with copper grades increasing to the west. Also at this time, drilling below the 2400 level intercepted a zone, referred to as the Lower zone, of weakly developed quartz-chalcopyrite stockwork veinlets and chalcopyrite disseminations, distinctly different from the typical skarn-style mineralization known at the Craigmont mine.

Work History

Craigmont Mines Ltd. originally staked the area in 1954. In 1956, a soil sampling and ground magnetometer survey were completed on the area and the following year drilling began with the S-15 discovery hole, which yielded over 4 per cent copper over 195 metres in the No. 1 orebody (Assessment Report 37888).

In November 1957, Canadian Exploration Ltd., Noranda Exploration and Peerless Oil and Gas optioned the property and formed the Birkett Creek Mine Operators Ltd., which was responsible for the construction and development of the open pit, underground development and mine facilities. In 1961, the mill was optioned back to Craigmont Mines Ltd.

The original Craigmont copper mine went into production in 1962, with underground mining ceasing in February 1982 as a result of the falling price of copper. The concentrator remained in operation processing the iron ore stockpiles until November 1982, when it was also shut down.

From the commencement of its operation in 1962 until 1970, Craigmont Mines Ltd. did not recover magnetite in its milling process, and on a material-balance basis there is estimated to be on the order of 5 000 000 tonnes of magnetite in the tailings deposit. The company reports that exploration completed in 1991 proved the presence of in excess of 1 000 000 tonnes of magnetite in the southerly one-quarter of the tailings.

Since the cessation of production in 1982, magnetite has been shipped from the stockpiles at Craigmont to western Canadian and United States coal producers, to be used as an essential component in their heavy media separation process.

Magnetite remaining in the original stockpiles as of 1992 represented approximately three years of industry requirements, based on the current level of usage. In order to replenish the stockpiles, in 1991 the company applied for the necessary government permits to construct a facility to recover the magnetite from the old tailings deposit. Production from the plant was scheduled to commence in the fall of 1992 (J. Harris [Yorkshire Resources], personal communication, 1992).

Through 1996, Seven Industries Inc. continues to produce approximately 60 000 tonnes per year of magnetite by processing the Craigmont tailings. The quality of the product has improved and the company is supplying most coal mines in western Canada (except Manalta and Line Creek). The company filed a conceptual design to create a new tailings storage dam (on top of the old one) that would allow the operation to continue for at least another 15 years (Information Circular 1996-1, page 10).

M. Seven is reported to have operated the Craigmont tailings up to and including 2001.

In 2002, Craigmont Holdings Ltd. was reported to be the owner of the Craigmont magnetite tailings operation, which was setup to process the tailings and recover approximately 70 000 tonnes of magnetite annually.

In 2003, Craigmont Mines Ltd. processed tailings from the old Craigmont copper mine and only produced 45 000 tonnes of magnetite. The magnetite is used in coal washing plants in British Columbia, Alberta and Washington state. The company is evaluating other magnetite sources, both on and off the property, as well as potential markets for hematite, which may also be recoverable.

In 2004, Craigmont Mines Ltd. signed an option agreement with Christopher James Gold Corp to purchase 50% of the 70 000 tonne per year magnetite operation for $3.5 million. A program of compiling historical geophysical and geological data to create three-dimensional models for further drill targeting was also completed at this time. A follow-up magnetic and induced polarization geophysical survey identified several targets. In 2005, an eight-hole drill program focused on the Embayment block and on the south slope of Promontory Hills.

Through 2007, Craigmont Mines Ltd. operated the Craigmont magnetite tailings operation located near Merritt, which employs about 30 people. Tailings from the old Craigmont copper mine are processed to recover approximately 70 000 tonnes of magnetite annually. The plant normally operates on a seasonal basis (March to December); however, due to strong demand, processing was expected to continue through the 2008–2009 winter. Remaining tailings are forecast to be exhausted within the one to two years following.

In 2012, Huldra Silver Inc. completed a 903 line-kilometre airborne geophysical survey on the area as the Thule property. This work isolated six magnetic anomalies (A through F) with the potential for magnetite skarn development, similar to the nearby Craigmont (MINFILE 092ISE035) deposit.

Also in 2012, Craigmont Mines Joint Venture ceased operations at the Craigmont magnetite operation due to depletion of economic reserves. Since 1991 the mine produced 1 167 000 dry tonnes of magnetite. Mining equipment was to be sold and the site reclaimed (Exploration and Mining in BC 2012).

In 2015, Nicola Mining Inc. completed a program of rock and soil sampling on the area as the Thule Copper-Iron property.

In 2016, Nicola Mining Inc. completed a program of prospecting, rock sampling, geological mapping and five diamond drill holes, totalling 1063.7 metres, on the Thule Copper property.

In 2017, Nicola Mining Inc. and Clibetre Exploration Ltd. completed a program of geological mapping; a 27.0 line-kilometre induced polarization survey; a 24.5 line-kilometre airborne magnetic survey; 29 rotary drill holes, totalling 392.0 metres, and 5 diamond drill holes, totalling 2994.7 metres on the Thule Copper property. The rotary drilling was performed on historical ore/waste stockpiles located close to the 3060 portal of the mine and yielded up to 1.03 per cent copper over 5 metres in hole P-34 and 0.8 per cent copper over 9 metres in hole P-72 (Assessment Report 37888).

In 2018, Nicola Mining Inc. completed a 9.0 line-kilometre ground magnetic and induced polarization survey, 70 percussion drill holes, totalling 1540.0 metres, and 16 diamond drill holes, totalling 6438.5 metres, on the area as the Craigmont property. The percussion drilling, which was completed on historical waste piles located near the 3060 portal and on waste material in the north and south mining terraces of the openpit, yielded up to 0.91 per cent copper over 4 metres in hole CC-RC-18-63 located near the 3060 portal and 0.25 per cent copper over 40 metres in hole CC-RC-18-12 located on the southern mining terrace (Assessment Report 38679). Also at this time, eight diamond drill holes tested potential skarn mineralization north and south of the openpit and identified a mineralized zone to the north, which yielded up to 0.54 per cent copper over 150 metres, including 1.05 per cent copper over 76.6 metres, in hole CC-18-02 (Assessment Report 38679).

In 2019, Nicola Mining Inc. completed a program of soil sampling and five diamond drill holes, totalling 3649.0 metres, on the area as the New Craigmont property. An inferred copper resource was calculated on the southern dumps, covering an area of approximately 82.5 hectares, and adjacent to the 3060 portal, covering approximately 1.4 hectares, yielding a total of 18 669 000 million tonnes grading 0.13 per cent copper, using a 0.06 per cent copper cut-off grade (Assessment Report 39102). Metallurgical studies on the waste pile material showed a significant reduction in mass, with an appreciable copper upgrading by utilization of the TOMRA XRT sorter. This is reported to provide a framework for the low-grade material to a be potentially viable resource. Floatation tests of the upgraded material, conducted by ALS metallurgy, resulted in a copper concentrate of 29.6 per cent copper and a 93.9 per cent magnetite concentrate. The economic contribution of magnetite was not used in the inferred resource.

Also at this time, diamond drilling targeted deeper sections below and west of the openpit to test the No. 3 orebody and the previously unidentified Upper and Lower zones. Drilling yielded intercepts including 0.34 per cent copper over 84.00 metres (387.00 to 471.00 metres down hole) in hole CC-19-73 on the Upper zone, 0.45 per cent copper over 44.00 metres (647.00 to 691.00 metres down hole) in hole CC-19-72 on the No. 3 orebody and 0.51 per cent copper over 14.00 metres (719.50 to 733.50 metres down hole) in hole CC-19-75 on the Lower zone (Assessment Report 39102).