Having decided what class of crushing machinery you will adopt, the first point is to fix on the best possible site for its erection.  This requires much judgment, as success or failure may largely depend on the position of your machinery.  One good rule is to get your crusher as reasonably high as possible, as it is cheaper to pump your feed water a few feet higher so as to get a good clear run for your tailings, and also to give you room to erect secondary treatment appliances, such as concentrators and amalgamators below your copper plates and blanket strakes.

Next, and this is most important, see that your foundations are solid and strong.  A very large number of the failures of quartz milling plants is due to neglect of this rule.

I once knew a genius who erected a 10-Lead mill in a new district, and who adopted the novel idea of placing a “bed log” laterally beneath his stampers.  The log was laid in a little cement bed which, when the battery started, was not quite dry.  The effect was comical to every one but the unfortunate owners.  It was certainly the liveliest, but at the same time one of the most ineffective batteries I have seen.

In a stamp mill the foundations are usually made of hard wood logs about 5 to 6 feet long, set on end, the bottom end resting on rock and set round with cement concrete.  These are bolted together, and the “box” or mortar is bolted to them.  The horizontal logs to carry the “horses” or supports for the battery frame should also be of good size, and solidly and securely bolted.  The same applies to your engine-bed, but whether it be of timber, or mason work, above all things provide that the whole of your work is set out square and true to save after-wear and friction.

Considerable difference of opinion exists as to the most effective weight for stamps.  My experience has been that this largely depends on the nature of your rock, as does also the height for the drop.  I have usually found that with medium stamps, say 7 to 7 1/2 cwt. with fair drop and lively action, about 80 falls per minute, the best results were obtained, but the tendency of modern mill men is towards the heavier stamps, 9 cwt. and even heavier.

To find the horse-power required to drive a battery, multiply the weight of one stamp by the number of stamps in the battery; the height of lift in feet by the number of lifts per minute; add one-third of the product for friction, and the result will be the number of feet-lbs. per minute; divide this by 33,000 which is the number of feet-lbs. per minute equal to 1 h.-p. and the result will be the h.-p. required.  Thus if a stamp weighs 800 lb. and you have five in the box, and each stamp has a lift of 9 in. = 0.75 ft. and strikes 80 blows per minute, then 800 x 5 x 0.75 x 80 = 240,000; one-third of 240,000 = 80,000 which added to 240,000 = 320,000; and 320,000 divided by 33,000 = 9.7 h.-p. or 1.9 h.-p. each stamp.

The total weight of a battery, including stamper box, stampers, etc., may be roughly estimated at about 1 ton per stamp.  Medium weight stampers, including shank cam, disc, head, and shoe, weigh from 600 to 700 lb., and need about 3/4 h.-p. to work them.