 In 1922, a group of miners attempted to locate the main leader's northern extension beneath the mantle of Mesozoic sediments.After sinking several shafts, they came across an auriferous lead at a depth of and at a distance of from a reef, which provided rich specimen stone.From then until the late 1930s, the Lower Camp was in constant production and has officially returned a yield of 35,016 ounces of gold.