The Big Slide property is located on the east side of the Fraser River where Kelly Creek enters the Fraser, about 26 kilometres southwest of Clinton. The showings were discovered in about 1872 by an Indian; subsequently the Foster Gold Milling and Mining Company was formed to develop the property. An unsuccessful attempt was made to recover the gold in the ore by means of a crude arrastra in about 1881. In 1886, after the ores from the mine had been tested in San Francisco, a 10-stamp mill with desulphurizing furnaces and chlorinating plant was constructed at the mine site. The property operated for a few months in 1887, during which time it was visited by G.M. Dawson of the Geological Survey of Canada. Material taken by Dawson from the concentrates assayed 13.9 grams per tonne gold and 31.9 grams per tonne silver. Active mining and milling was discontinued in 1887 after a period of three or four months operations.

The property lay idle until 1928 when the Big Slide Mining & Smelting Development Company Limited was formed to acquire a group of 14 claims. Development work was carried on until 1933 when the assets of the company were taken over by Grange Mines Limited. A 25 tons per day mill was in operation from 1933 until August 1935 when the mine closed.

Grange Consolidated Mines Limited, incorporated in 1937, purchased the property from Grange Mines Limited and carried on intermittent operations until June 1938; underground maintenance work was carried on until 1941; the claims subsequently lapsed.

A group of 16 claims, adjoining to the south of the claims held by Grange Mines Limited, was acquired by Pavillion Gold Mines Limited in 1933 (see Pavilion, 092INW083).

In 1946, Rusdon Gold Mines Limited acquired the ground formerly held by Grange Consolidated Mines Limited and Pavillion Gold Mines Limited. During the year 579 metres of diamond drilling was done in four holes.

The Big Slide property has been developed on seven levels, three of which are adit levels. Number 3 level is the main haulage level, and from it access to the lower workings is by winze. In 1935, when the seventh level was opened, 79 metres of drifts, 16 metres of crosscuts and 15 metres of raises were run before the mine closed. The mill erected in 1886 was destroyed by fire.

The rocks in the vicinity of the Big Slide mine are fractured, sheared and faulted shales, cherts and greenstones with occasional interbedded limestone of the middle Permian to Middle(?) Jurassic western belt of the Cache Creek Complex which are here intruded by a small stock of Early Jurassic diorite. In the mine workings the diorite is the dominant rock type, and forms the host for two narrow lenticular quartz veins, referred to as the Footwall and Hangingwall veins. These veins pinch and swell and may reach widths 0.9 to 1.2 metres, but 20 centimetres is average. The Footwall vein has a much flatter dip than the Hangingwall vein and probably joins it at depth.

Northwest of the mine workings, the Hangingwall vein which is the stronger of the two, outcrops in the bluffs for 305 metres where it strikes 330 degrees and dips 70 degrees northeast.

The ore consists of pyrite, pyrrhotite, arsenopyrite, chalcopyrite, marcasite, limonite and native gold in a gangue of quartz and minor carbonate. The native gold is visible only in dense pyrite. The ore commonly occurs as banded sulphides with quartz, but in the wider sections of the veins may occur as isolated patches of sulphides. In most parts of the underground workings a thin parting of gouge appears between the vein filling and the walls.

An ore shoot between the number 3 and 5 levels in the area adjacent to and northwest of the number 2 winze connecting these two levels, has a block of ground averaging 31 centimetres in thickness that contains 861 tonnes of probable ore grading 16.2 grams per tonne gold and 42.1 grams per tonne silver (Richmond, 1933).

Intermittent production from 1934 to 1940 totalled 7214 tonnes mined and 6895 tonnes milled from which 76,607 grams of silver, 39,904 grams of gold, 6810 kilograms of copper and 54 kilograms of lead were recovered.