British Columbia’s gold output nearing peak set back in 1939

When final figures are in, they should verify that mineral exploration in British Columbia reached an all-time high in 1987.

The high level of activity was prompted by continued strong interest in precious metals, flow- through financing, continued exploration successes and the opening of another new gold mine at Hedley. Major diamond drill programs in 1987 were up 68% over 1986 to 150. The number of mineral claims staked to the end of September was 74,500, up 54% from 48,300 for the same period in 1986. Exploration expenditures are expected to be in the order of $130 million, up from $94.2 million in 1986 and $80 million in 1985. This, again, should be a record.

Recent estimates are that 1987 gold production is going to be about 350,000 oz or nearly 11 tonnes, up one quarter from the 280,000 oz or 8.7 tonnes produced in 1986. By 1990 production is expected to exceed 600,000 oz or 18.7 tonnes and thus surpass the peak annual production of 18 tonnes achieved in 1939.

There were at least 25 major underground exploration projects in British Columbia during 1987, and at least 50 properties can be listed as having meaningful reserves that are, or are close to being, economically viable.

A total of 20 projects have formally entered the government permitting process — most of these projects are for gold and one is for silver.

As in previous years, gold, silver and polymetallic deposits with precious metal values continue to be found in four main geological environments, with a sprinkling of deposits that are transitional between those models. Gold-enriched skarns

The importance of gold-enriched skarn deposits was emphasized earlier in the year by the opening of the Nickel Plate mine near Hedley. This old mine, now in its third life, has already produced 48.4 million g (1.556 million oz) of gold from 3.6 million tonnes of underground ore between 1902 and 1957.

The current open-pit operation is at a daily rate of 2,160 tonnes per day. Pitable reserves are 8.9 million tonnes grading 4.56 g per tonne with an additional 1.8 million tonnes of similar grade mineable by underground methods. Together with the past production, this brings the known gold content of this deposit to roughly 90 tonnes, (2.92 million oz), with excellent prospects for discovering additional reserves.

British Columbia has more than 300 other recorded skarn occurrences, roughly one-third of which are known to contain gold. Some of these have produced in the past; others are potential producers.

The Tillicum Mountain property of Esperanza Explorations has known reserves of 45,500 tonnes grading 34.28 g per tonne and a drill-indicated potential in excess of 182,000 tonnes with a grade of 20.5 g per tonne. Esperanza has also enjoyed encouraging early results on its recently acquired Hailstorm Mountain property, nearby.

Other potentially economic gold- enriched skarns include deposits at Zeballos on Vancouver Island, on Banks Island and on Texada Island.

The Geological Survey Branch has initiated a study of gold skarns in British Columbia. Interested persons should contact the Geological Survey Branch for information.

Another deposit which is generally regarded as a porphyry system, but which has skarn affinities, is the qr deposit of Placer Dome, west of Likely. Gold occurs in intense propylite alteration in Upper Triassic volcanics and sediments cut by a consanguineous differentiated syenitic stock. Drill-indicated pitable reserves are in excess of one million tonnes grading 6.8 g per tonne gold. This deposit is at the feasibility stage.

The favorable geology that hosts the qr deposit continues to the northwest along the axis of the Quesnel trough where intrusions similar to the qr stock are known to occur in an underexplored area of poor exposure. These are obvious targets for more qr-type deposits, and are a challenge to the explorationist. However, recent logging roads in the area have greatly improved access. Epithermal deposits

The search for gold-bearing epithermal systems has continued at a brisk pace for several years with considerable success. The Blackdome Mine, 250 km north of Vancouver, began production in May, 1986, at 165 tonnes per day from a classic, high-level epithermal vein system hosted in Eocene sub-aerial volcanic flows and pyroclastics. This mine reached full payback of its $18-million capital investment in the first nine months of operation. New ore is being found faster than reserves are being mined. The Toodoggone camp, 300 km north of Smithers, has been one of the hottest exploration areas in the province for several years. More than $10.6 million was spent in this camp in 1987, compared to $3.5 million the previous year. The increased activity is attributable to three factors:

* The completion of road acess to the area, funded 50% by a $4.5 million provincial government grant.

* The decision by Cheni Gold Mines to go ahead at a planned production rate of 450 tonnes per day on its Lawyers deposit.

* The considerable success of other projects in the area.

Gold and silver in Toodoggone occur along the central axis of a 100×20-km belt of Early Jurassic subaerial andesitic volcanics and are best developed in epithermal systems such as Cheni Gold Mines’ Lawyers deposit, which has reserves of 1.7 million tonnes grading 6.7 g per tonne gold and 243 g per tonne silver.

The Al deposit of Energex Minerals, has pitable reserves of 225,000 tonnes grading 8.6 g per tonne gold.

Other deposits at earlier operation stages are: the Chappelle deposit of Multinational Resources with reserves estimated at 45,000 tonnes grading 17.1 g per tonne gold; the St. Joe Gold Silver Pond deposit; and the Manson Creek Resource Mets deposit, which has reserves of 144,000 tonnes grading 11.3 g gold per tonne.

Significant developments in the Toodoggone this year have been the discovery of above average grade gold/silver mineralization at depths of more than 330 m at Lawyer’s Cliff Creek zone, the tracing of mineralization by drilling and trenching over a strike length in excess of 750 m at the Al deposit, and the discovery of gold-bearing skarn at Cheni Gold’s Acapulco prospect.

Another very promising epithermal deposit is the Mount Washington property of Better Resources on Vancouver Island. Mineralization is associated with a Tertiary quartz porphyry and breccia irruptive centre cutting Cretaceous Nanaimo Group sediments and Triassic Karmutsen basalts. The mineralization occurs in tabular, shallow-dipping alteration zones locally up to 30 m thick. Sulphides are mainly pyrite and arsenopyrite.

At the end of 1986, the company had outlined 212,300 tonnes of drill- indicated reserves grading 7.9 g per tonne gold and 39.4 g per tonne silver, as well as 438,000 tonnes of inferred reserves grading 6.2 g per tonne gold. New reserve figures have not yet been released, but more than 100 holes were completed in 1987, as well as a 300-m adit that has yielded a 5,400-tonne bulk sample. Gold assays from blast holes and muck samples from the adit have returned roughly double the values obtained in surface diamond drill holes.

On Graham Island in the Queen Charlotte Islands, City Resources (Canada) has completed a thorough re-assessment of the Cinola deposit which represents the exposed middle to upper levels of a Tertiary epithermal hot-spring-type precious metal system. Pitable reserves are about 25 million tonnes grading 2.47 g per tonne gold and 69.6 g per tonne silver, representing roughly 62 million g (2 million oz) of contained gold.

A number of other interesting epithermal systems are under exploration throughout the province. Two of particular interest are the Brett property, west of Vernon, and the Vault property, west of Okanagan Falls; both are vein systems in Tertiary rocks. Massive sulphide deposits

Another important target is massive sulphide mineralization with precious metal values. On Vancouver Island, Abermin has continued an aggressive exploration program on its Lara property, near Chemainus, and has announced its decision to go underground with a decline.

Min
eralization occurs in Devonian felsic volcanics of the Sicker Group and has many similarities with the hw deposit of Westmin Resources at Buttle Lake, approximately 100 km to the north. To date, more than 20,000 m of drilling in 148 holes has been completed.

The zone has been tested to a depth of 150 m and over a strike length of 400 m. Drill-indicated reserves are in excess of 800,000 tonnes grading 7.9 g gold per tonne, 230 g silver, 4.5% zinc, 1% lead and 0.75% copper.

The Adams Lake area, 65 km northeast of Kamloops, has been the focus of intense exploration activity since late 1983, when A. Hilton discovered gold-bearing massive sulphides (Rea Gold) near Johnson Lake.

The discovery in late 1985 of the nearby Samatosum silver deposit by Minnova has opened up a new target in this area. This deposit has entered the government permitting process in late 1987. Mineralization is localized in tuffaceous sediments of the Palaeozoic Eagle Bay assemblage; these lie on top of a thick sequence of mafic volcanics of similar age. Sulphides include tetrahedrite, galena, sphalerite, chalcopyrite and pyrite. Similar mineralization is being explored on the nearby Twin and Kamad properties of Esso Minerals Canada.

In the extreme northwestern corner of the province, Geddes Resources is carrying out a $17.7- million underground program at the 270-million-tonne-plus Windy Craggy copper/gold/cobalt massive sulphide deposit. An adit was collared in late May, 1987, and is to be completed in February, 1988.

A number of gold deposits that are transitional between epithermal and porphyry systems occur in northwestern British Columbia and are in the advanced exploration and development stage.

The Stewart-Iskut River gold belt is one of the busiest, most exciting and promising areas in the province. At the southeast end of this belt, near Stewart, Westmin Resources is at the production decision stage on its Silbak Premier- Big Missouri project. Quartz stockwork mineralization occurs in Early Jurassic andesitic volcanics intruded by the subvolcanic Premier porphyries.

Reserves are reported at 6.3 million tonnes grading 2.33 g per tonne gold and 88.8 g per tonne silver for Silbak Premier, and at significantly more than 1.6 million tonnes grading 3.60 g per tonne gold and 2.9 g per tonne silver of the nearby Big Missouri.

An open-pit operation at 1,800 tonnes per day, with capital costs in excess of $76 million, is anticipated for this project.

If Silbak Premier’s past production is added to the 20.6 million g (0.66 million oz.) of gold and 614 million g (19.64 million oz) of silver represented by the current reserves, the total known mineable precious metals contained by these two deposits are 76 tonnes of gold and about 1,875 tonnes of silver.

Forty-three kilometres northwest of Silbak Premier, another very active camp is the Sulphurets area, where at least 18 separate mineralized zones have been located in Early Jurassic volcanics intruded by syenites. Mineralization in these zones ranges from copper/molybdenum/gold to disseminated gold to complex gold/silver vein systems and stockworks to simple epithermal veins.

The West zone at Brucejack Lake continues to be the target of an aggressive underground development program by Newhawk Gold Mines. Drill-indicated and inferred reserves were 1.4 million tonnes grading 11.66 g per tonne gold and 785 g per tonne silver at the end of 1986. During 1987, the company spent $5.1 million in additional drilling and underground exploration and in building a road and barge link to the property from Highway 37.

Perhaps the most exciting developments are occurring 50 km to the northwest, at the Iskut River end of the belt where Skyline Explorations is moving ahead with production plans for its Stonehouse (Reg) deposit.

Gold/silver/copper mineralization here occurs in a number of lenses of veins along a fracture system in Lower Jurassic volcaniclastic and sedimentary rocks that has been traced for a strike length of 1.5 km. This deposit is transitional between a porphyry system at depth and a mesothermal vein system above. Recent company estimates put measured, inferred and indicated reserves at 845,000 tonnes grading 25.02 g gold per share, 29.14 g silver and 0.76% copper, with excellent geological potential for more.

The Iskut camp was one of the busiest areas in the province in 1987, with exploration expenditures of roughly $10 million and at least 15 companies carrying out major programs.

Most notable among these is the Cominco/Delaware Resources joint venture on the nearby Snip property, where a major drill program has produced excellent results from a system of well-defined quartz veins over a strike distance of 900 m and a vertical distance of more than 120 m. The company has recently stated that, based on existing results, 1.1 million tonnes can be inferred grading 24 g per tonne gold. Facilities at this property are being upgraded for winter work in anticipation of an underground program.

Underground development work continued at the Dome Mountain property of Teeshin Resources 40 km east of Smithers. Gold/silver mineralization occurs in a number of mesothermal sheeted quartz veins in Early to Middle Jurassic volcanics and sediments. Reserves are estimated at 290,000 tonnes grading 14.95 g per gold tonne and 96 g silver. This deposit is at the feasibility stage.

West of Dease Lake, the North American Metals/Chevron Minerals joint venture continued with underground development work on the Goldben Bear deposit. Gold mineralization occurs in silicified and breccia zones along a major fault zone between Permian limestone and upper Triassic andesites. This deposit is of the vein type with epithermal characteristics. The best mineralization is in flexures or rolls in the fault system.

Reserves for the Bear Main zone are aboiut 135 million tonnes grading 13.1 g per tonne gold. The deposit is at the feasibility stage. The mine received approval in principle from the government although a road corridor has yet to be selected.

Southwest of Revelstoke, near the old mining town of Camborne, very promising results have been obtained by Granges Exploration from extensive drilling on the Goldfinch property. Native gold and tetrahedrite occur in structurally controlled quartz veins in Paleozoic metasedimentary and metavolcanic rocks of the Broadview and Jowett Formations. A $3-million underground program is to begin immediately.