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A Stamp mill is a mill, a type of machine or device used to break material into smaller pieces, either for further processing or for extraction of metallic ores. Breaking material down is a type of Unit operation.
Usage
Stamp mills were use in early paper making for preparing the paper-stuff (pulp), before the invention of the Hollander beater. They were used in mining for breaking ore, and in oil-seed processing for prior to pressing the oil from the milled seeds. Early mills were water powered but mills can be steam, water, or electric powered.
Arrangement
Stamp mills comprised a set of heavy wooden (or later, steel) beams with a metal facing on the bottom, loosely held vertically in a frame, in which the beams could slide up and down. They were lifted by cams on a horizontal rotating shaft. As the cam left the beam it fell onto the material being processed, then picked up again at the next pass of the cam. Each frame and beam set is sometimes called a "stamp" and mills are sometimes categorised by how many stamp sets they have, i.e. a "10 stamp mill" has 10 sets. They usually are arranged linearly, but when a mill is enlarged, a new line of them may be constructed rather than extending the line. Abandoned mill sites (as documented by industrial archaeologists) will usually have linear rows of foundation sets as their most prominent visible feature as the overall apparatus can exceed 20 feet in height, requiring large foundations.
Some ore processing applications used large quantities of water so some stamp mills are located near natural or artificial bodies of water. For example, the Redridge Steel Dam was built to supply stamp mills with process water.
History
Stamp mills were in use from the Renaissance period onwards. The first one in the U.S. was built in 1829 at the Capps mine located near Charlotte, North Carolina. see Mineral Resources of the Blue Ridge and Piedmont, page 143 They were superseded in the 2nd half of the 19th century in many applications by more efficient methods of processing. However their simplicity meant that they were used in remote areas for ore processing well into the 20th century. (19th century advertisements for some mills highlighted that they could be broken down, packed in by mule in pieces, and assembled on site with only simple tools) They were quite common in gold, silver and copper mining regions of the US in the latter half of the 19th and early 20th centuries, as the noble metals often occurred in metallic ores where physical crushing would give good separation results.
See also
- Hammer mill - A more modern device that also can crush material to fines.
- Ball mill - a horizontal cylinder containing metal balls to crush the material
- Stamp sand - the product of ore mills
References
External links
- Paymaster Stamp Mill near Lewiston, California
- Standard Stamp Mill picture gallery, near Bodie, California
- 30 stamp mill near Cordova, Ontario
- Mining History Illustrations 5 cutaway drawings of mills produced by the Joshua Hendy Iron Works Company during the early 1900's.
"Stamp mill"