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TREATMENT OF STJLPHVJRET ORES AT CHARACTERISTIC MINES. 123
filling, had been found, the ore was not rich enough to mill. On the 235-foot level a horizontal diamond-drill hole (over 150 feet in length) was bored in the hanging, but no other parallel ore-body was found. Cross-fissures, from 3 to 6 inches in thickness, are met with in the mine, striking X. 30° to 35° W., with a vertical dip, and intersecting, though not faulting, the ore-bodies. These fissures are filled with coarse crystalline caleite, sometimes carrying inconsiderable amounts of pyrite. The structure of the vein-quartz at the Franklin is banded, and its character is milky, glassy. The sulphurets consist mainly of coarse crystalline pyrite (with very little chalcopyrite), usually occurring in bunches. Although the ore is over 50 per cent, free-milling, gold visible to the eye is of very rare occurrence. The fineness of the gold is 980 to 989.
The property of the Creighton Mining and Milling Company comprises some 1800 acres. The first work done here was by open cuts in the outcrop of the ore-shoots. After the death of Mr. Franklin, the original owner, the mine was worked for a long time by his widow.
Before the adoption of the chlorination process for treatment of sulphurets by the present company, a cyanide plant was erected and operated for a short time.
The present condition of the mine is shown in figure 20, giving a vertical section along the strike. The mine is worked entirely through Xo. 2 shaft (1), driven in the hanging wall to a depth of 215 feet, at which point it strikes the vein. From this level work is carried on to a total depth of 430 feet by a slope on the dip of the vein and the pitch of the ore-shoot, resting on a small horse of poor ore.
The method of mining the ore is as follows: Levels are run every 100 feet, and the ore-lenses are entirely stoped out, leaving the intervening bodies of low-grade material as pillars. The levels are connected by a series of raises, their number depending upon the length of the ore-shoots. The ore is then stoped by underhand work, the raises acting as ore-chutes (mill-holes), and the cars being loaded directly from pockets in the level below. Xo pillars are left below the levels, the track, when necessary, being carried over the worked-out stopes on stulls. Only such timbers as are necessary to assist the men in their work are used, the walls requiring no support. All the material stoped is hoisted and milled, leaving no waste filling in the mine. Air-drills are used almost exclusively; for stoping, a Baby Band with J-inch steel is used, while drifting is done with 3^-inch cylinder Sergeant machines. The ore is raised in cars of -|-ton capacity, first up the incline by underground hoisting engine (4), and then trammed to the bottom of the vertical shaft, from where they are hoisted to the surface on cages. Xo. 1 shaft (2) is used for ventilation and as a pipe-way. The mine is not a wet one. a small steam-pump, situated immediately below Xo. 2 shaft, taking
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