HORSE WHIM.
The horse whim is used in developing many a western prospect. The windlass does not work well below forty feet, and where fuel and water are to be had any sensible man will use steam power for deep mining, but there is a gap between the windlass and the steam hoist which the horse whim fills acceptably. To a depth of 300 feet a horse whim can usually handle the rock and water. It is inexpensive, in the first outlay, and costs but little to run. You can bring your bucket from a shaft a hundred and fifty feet deep in two and a half minutes, and with a seven hundred pound capacity in the bucket, in forty-five trips you could raise fifteen tons a day. A shaft three hundred feet deep would require four hours' steady work to bring to surface the same amount. A fair speed with a one-horse whim from a three hundred foot shaft is one hundred buckets per shift of ten hours, but the prospector rarely has to figure on shafts of that depth. If the mine turns out well it is likely to be in the hands of a powerful company (of which he should be the principal shareholder) before the three hundred foot level is reached. The weight of the horse whim is about eight hundred pounds. It can be taken to pieces and packed anywhere that a mule can travel; the heaviest piece will not weigh more than a hundred pounds.
PROSPECTING MILL WITH HORSE POWER.
A small stamp mill, run by horse power, is a very favorite machine with western men, where the ore is free milling. The mortar in which the stamps work has copper plates amalgamated with mercury inside, and copper tables with amalgamated plates over which the pulp passes after oozing through a fine screen in front of the mortar. These little mills are so constructed that they can be taken apart or put together in an hour or two. They require but one horse power and will do good clean work up to their capacity. The following are the specifications of a good one:
| Total weight | 1,500 pounds. |
| Weight of heaviest piece | 350 pounds. |
| Weight of stamp | 100 pounds. |
| Drops per minute | 60 to 80. |
| Capacity per hour | 300 to 400 pounds. |
| Diameter of pulley | 30 inches. |
| Price, with horse power, | about $350. |
A diamond drill is a most useful adjunct to exploration of a mine or deposit. It is, essentially, a hollow drill which may be lengthened at will, rotating rapidly and carrying a crown of "bort" or black diamonds at its extremity, that eats into the strata very quickly. Holes 3,000 feet deep have been driven by the diamond drill, but such extensive investigations of the earth's crust are tremendously costly, and may only be undertaken by governments or rich companies. For a depth of 700 feet, however, the expense need not exceed $2,100. The cost of the plant for drilling would be $3,500 more. Water is pumped down the hollow center of the drill, to keep it cool. The great advantage of the diamond over the percussion drill is that it permits the saving of a core, so that the character of the rocks and minerals passed through may be known. The diamond drill does better work in hard strata than it does in soft. The rate, in limestone, may be about two feet an hour, down to a depth of 200 feet.
A complete outfit for boring with the diamond drill includes a steam engine and boiler, diamond crown, lining tubes, rods, and various minor accessories.
Hydraulic mining is the cheapest known method of recovering gold. In four years the North Bloomfield Mining Company of California worked 325,000,000 cubic yards, which yielded only 2.9 cents of gold per cubic yard, and realized some profit. Very poor gravel will pay when the conditions are good. Cheap water, grades of four inches in a hundred, ample dumping room, big banks of light gravel, large areas of deposits, labor at a dollar a day, and a clever superintendent, make a combination that will yield a profit out of three-cent gravel.
Miners speak of "surface" and "deep" placers; of "hill claims;" of "bench claims" on the old river terraces; of "gulch diggings;" of "bar claims" on the sand bars of existing rivers; of "beach sands" or those that in a few favored localities border the ocean. A "sluice" is a long boxway to catch the gold; a "drift" is a tunnel into the gold-bearing gravel; and hydraulic diggings are those in which water under pressure is used to disintegrate the gravel.