File:PN Russell and Company Stamper Battery - image 5.jpg

English: A device for crushing ore. The parts of the battery are: cams; dies; guides; kingposts; mortar box; shoes; stamps (or stampers); tappets (see attached diagram). Cams: curved arms fixed to a powered shaft (the camshaft), which sequentially raised the stamps in a battery to facilitate ore-crushing. Once raised, each stamp free falls onto the ore contained in the mortar box. Dies: replaceable hammering surfaces, which are located in the mortar box in a battery (stamp mill). Dies were usually made of cast iron and weighed 80 to 116 pounds each (32 and 46 kilograms, respectively), varied in thickness from 3 to 5 inches (76 and 127 millimetres, respectively), and when worn out and replaced weighed 35 to 45 pounds (14 and 18 kilograms, respectively). It has been estimated that for every ton of ore crushed, the weight of the dies was reduced by 5.5 to 8.5 ounces (155 and 240 grams, respectively) [Rickard, H. A. (1898). The Stamp Milling of Gold Ores. Scientific Publishing Co., New York, USA]. Guides: iron or hardwood cross-members mounted between the kingposts in a battery. They enable the stamper shafts to move up and down but rigidly control their horizontal movement. Kingposts: vertical wood or pre-cast steel posts which support the stampers in a battery. The kingposts for this battery are pre-cast steel. Mortar box: the large cast iron boxes fitted with heavy cast iron dies in which five head (usually) of stamps dropped onto ore or cement (especially in regard to alluvial gold deposits) and crushed it to a pulp, which then passed through mesh screens at a rate of about 7 tonnes per day. Shoes: the replaceable hammer heads attached to the base of each stamp shaft in a battery. Each shoe has a protrusion, which fitted a socket in the end of the shaft. Stamps (or stampers): each battery (stamp mill) was composed of various numbers of stamps usually in groups of five per mortar box. Each stamp consists of a shaft with a stamping shoe attached to its lower end, and a tappet positioned at about the midpoint. Large battery complexes had stamps that could weigh 1250 pounds (500 kilograms) each. The stamps, driven by a cameshaft, were lifted and then fell in a particular sequence, pulverized the ore after it had been reduced initially to about 2.5 inches (63.5mm) size by crushers. The stamping surfaces (shoes and dies) had to be replaced regularly. Tappets: thimble-shaped components attached to the shafts of stampers. The tappets were designed to engage the cams on the camshaft, which in turn lifted each stamper in sequence. Stamp sands: essentially tailings, the result of crushing ore in a battery/stamp mill. The fine waste sand fraction to the original ore, after its metal content has been removed. Frequently discharged into waterways, or flushed downslope from a battery often creating a distinctive site feature and indicator of the former existence of a battery upslope (Ritchie, A. R. and Hooker, R. (1997). 'An Archaeologist's Guide to Mining Technology', Australasian Historical Archaeology, Vol. 15, pp. 3-29 (23).