Gold properties have different gold mineralization and the gold grade is variable. For this reason prospecting must involve low and high grade deposits. A slightly explored gold property carrying low grade gold ore that may be expected just to pay its way should be explored, as higher-grade ore may be found. Any large deposit of even very low-grade material should be given at least a preliminary examination, as the constant improvement in metallurgical processes is steadily rendering payable ores of lower and lower grade. The waste material of 10 years ago is the ore of today, and the same advance may be reasonably expected in the future.
Prospectors have noted that a large body of low-grade ore is more likely to persist than a smaller body' of high-grade ore. Small gold mines, unless containing good ore and requiring little equipment (and these are rarely purchasable at a reasonable price), are usually not profitable. The cost of all equipment must in the final analysis be charged against the tonnage of ore extracted, and one mine may yield an attractive profit where two mines each containing one-half the tonnage of the same grade may both net losses. Furthermore, a small property may be a poor strategic position to secure good smelting or freight rates.
It is important to mention that sampling is costly work if properly carried out, and no other kind of sampling is of any value. The ideal sample is a uniform groove, or channel, across the full width of the ore, and no more; how closely this may be approached in practice will depend upon the material sampled and upon the time and care given to the work. The basic equipment for sampling is a hammer and it is preferable to any other tools in cutting samples; a prospector's pick will do good work in soft, uniform ground, but in harder material, even if the point and hammer-end are alternately used, is likely to have a selective effect, and samples taken with a pick are not above suspicion.
To catch the sample a cloth is best, spread out so as to catch all chips. If the ground is loose and masses are likely to fall, the sample is best caught in a box, which is also used where fine, rich material is likely to sift out of cracks and vugs and so find its way into the sample. To break down samples a crusher is convenient, but two large, tough stones of rock such as may be found in any creek bed, one to lay the ore upon and the other to pound with, yield the maximum result for coarse breaking; unless the ore is very hard, the abrasion of the stones is negligible. To cut down samples, rolling and quartering on flexible mat is a good method, but where many samples are to be taken, a Jones sampler with four pans, or a riffle, is quicker and more certain to do accurate work. A simple apparatus to permit the cutting of samples in a shaft has been used with great saving of time and expense over erecting platforms. This consists of a short seat, this seat is fastened to the end of the crane rope, and, straddling the rope, the sampler is lowered to the point where a sample is to be taken, meanwhile holding the pole parallel to the rope so as to permit the descent. Arriving at the point where the sample is to be taken, the pole is allowed to fall against the opposite wall, the end of the pole catching in an inequality of the rock, the seat is hoisted a few inches, and the sampler, with feet braced against the face sampled, is held firmly and safely in position, with both hands free to work. The sample may be caught in a bag held between the feet, or a canvas receptacle may be rigged in front of the sampler, or the sample may be allowed to fall on a canvas spread over the bottom of the shaft, which should be protected from the impact of the falling ore by a few boards.