Important as the Larose discovery was it was not the first silver discovery in the camp. On August 7, 1903 two tie cutters supplying the T. & N. O. Railway, on contract, found "glittering rocks" on the south shore of Long Lake. James McKinley and Ernest Darragh, both from the farming community of Plantagenet, Ontario, had acquired some prospecting knowledge during a previous journey to the gold fields of California. They had learned to test nuggets by biting them with their teeth. When they tested the "glittering rocks" they knew they had found native silver. A search of nearby outcrops disclosed the vein from which the rock fragments came.

After staking their claim they gathered up several bags of samples and proceeded by train to Ottawa and arranged  for tests at a local laboratory. The results were not encouraging; only small amounts of bismuth were found in the samples. Still determined, the men took their samples and headed for Montreal and searched out Dr. Milton Hersey at McGill University. The assay laboratory at McGill was known for its expertise in evaluating ores of precious metals. It was a wise move the samples assayed at 4000 ounces of silver per ton.

McKinley and Darragh returned to Cobalt and filed their claim on August 14, 1903. In their haste they neglected to attach a map showing the location of the claim. This error caused a delay of several weeks and the claim was not officially recorded until October 6, 1903. This was almost three weeks after the Larose copper find was registered. Later the same month another silver find would be recorded and the basis for the Great Silver Rush established.

This mill, named for the first discoverers of silver in the camp, was the first one to operate in the summer of 1907. Its capacity was only 15 tons per day but was gradually enlarged to 225 tons per day by the year 1913.

By design it was a typical "gravity mill" built on a hillside so that crushed ore would flow downward by gravity to ball mills, jigs and vibrating tables. The ore came from 8 shafts on the property and from the Savage Claim at Cart Lake (Site # 5) by means of an aerial tramway. The mill ceased operations in 1927 having recovered more than 13,000,000 ounces of silver.