1855 Wheal Hearle commenced 1855 as a cost book company.
1860 shares in the mine, previously held by six individuals, were offered for sale to the public. The mine was equipped with a 10-inch winding engine and a 30-inch pumping/stamping engine. The Engine Shaft, sometimes referred to as Borlase's Shaft, (a lode called Borlase's is shown on Symons' 1857 map of the St Just district), on the Bill Lode, was 8 fathoms below the 80-fathom level and the new Flat-rod Shaft on the Boscaswell Downs Lode was 5 fathoms deep. Eleven other lodes were in the sett. Man power comprised 23 men and 5 boys on tribute and 22 men and boys on tutwork.
1860 it was decided that more stamps were needed to augment the 15 heads already in use. By this time Borlase's Shaft had reached 90 fathoms below adit while on the 60-fathom level east a junction was expected with Bridgework Lode. The extra 6 heads were in operation by January and Borlase's Shaft connected to the 100-fathom level by the end of March. Production appears to have averaged about 20 tons of black tin per quarter.
1862 the Engine Shaft was 7 fathoms below the 110-fathom level. The Engine Shaft was sunk to the 122-fathom level by September and levels commenced east and west of the shaft. In November there is a note that 'the new stamps is gone to work' which suggests that even more heads had been attached to the engine.
1863. Little work seems to have gone on at the mine from here; the lower levels (below the 90-fathom level) were extended but by February the operation had disappeared from both the dividend and progressive lists in the Mining Journal. The mine was employing 101 people in May 1863: 28 men and 6 boys on tutwork, 15 men on tribute and 18 men, 14 boys and 20 girls at surface. About this time the Skip Shaft was opened up through old workings to the 80-fathom level. By the end of July it was just above the 122-fathom level, still in old workings. The new skip running in the shaft was in action almost straight away and by mid-November the ore that had accumulated at the 100 and 110 fathom levels had been cleared. Twenty-four heads of stamps were in operation.
1864 In February the Engine Shaft was down to the 130-fathom level and balance bobs were being fitted. By June the work was completed, and pumping beams in the 100 fathom level were pumping water from the Skip Shaft, which was being deepened, to the Engine Shaft.
1864 and 1865 Little is reported from the mine apart from working on the deeper levels of the mine. By December Skip Shaft was 4 fathoms below the 130. By June the following year only 83 persons were employed. By this time the mine had reached its ultimate depth of 150 fathoms.
St Just Area Mines, Cornwall