Echo Bay gives nod to Lamefoot deposit

A new gold deposit is set to come on stream for senior gold producer Echo Bay Mines (TSE).

The Lamefoot deposit is the latest in a string of five deposits to be put into production at the Kettle River project near Republic, Wash. The 13,400-acre project started up in early 1990 and has since produced a total of 337,000 oz. from four deposits: Kettle, Key East, Key West and Overlook. All of these are hosted in a sequence of folded and faulted, Permian-aged, clastic and carbonate rocks.

Gold mineralization occurs within two distinct settings in this sequence. In the deeper portions, it occurs in massive magnetite- and sulphide-replaced limestones that are coincident with a tectonic contact between the lower limestone unit and upper clastic sediments. The second setting is associated with gently dipping, sheeted vein swarms that are up to 150 ft. thick. These swarms are hosted within the clastic rocks, where gold is associated with sulphide-bearing quartz veins.

Lamefoot consists of 1.6 million tons averaging 0.19 oz. gold per ton. Originally, gold at Kettle River was produced from underground operations at the Overlook deposit, with minor contributions from the Kettle deposit, 25 miles north of the mill.

Once mined, ore was trucked to the mill, where carbon-in-leach techniques were applied.

When mining of ore from underground became prohibitively expensive, operations were refocused to the Key East and Key West pits, and by 1992 these two deposits had become the source of almost all production. Situated 3 miles from the mill, Lamefoot was discovered in 1990 when drilling encountered “ore-grade material” 500 ft. below surface. Mineralization was intersected over widths ranging from 50 to 100 ft. along a strike length exceeding 1,500 ft. By the end of 1991, a probable resource of 148,000 oz. had been delineated.

Mining of the deposit will begin in the upper levels, and it is anticipated that ore will be fed to the mill before the new year.

In 1993, the Kettle River project produced 73,431 oz. at a cash cost of US$277 per oz. Proven and probable reserves stand at almost 2 million tons averaging 0.16 oz., which includes more than 300,000 tons of stockpiled ore. Total reserves are equivalent to 415,000 oz., according to Echo Bay. Exploration is continuing, with a sixth deposit, the K-2, at an advanced stage and likely to be the next deposit mined.

In 1993, Echo Bay completed 60,000 ft. of drilling at K-2. Plans for the past year included constructing a portal and completing 2,000 ft. of adit drifting, which were to have enabled the company to complete initial underground drilling and definition drilling.