Monday, May 27, 2013

Equipment of the James Stuart Mill

The James Stuart mill at Phillipsburg, built in 1867 for silver ores, is a stone building ; engine, 50 horse-power ; boilers, 40-inch diameter and 20 feet long; runs ten stamps, 650 pounds each ; six Wheeler pans, 4 feet in diameter, and three concentrators, 8 feet in diameter ; stamps and pans are geared to make from 60 to 75 drops and revolutions per minute. Capacity from 12 to 15 tons per twenty-four hours, according to quality of ore. It has crushed about 1,000 tons of quartz in all, which yielded about $100,000. The rock worked was principally croppings and ore taken from near the surface. The mill is now idle, awaiting re- pairs of crank and cylinder. It cost, all told, about $75,000, currency, and is considered the best mill in the Territory. It is situated in Flint Creek district, which first became generally known in the winter of 1866.
Report of Rossiter Raymond to Congress for 1869.  
A bill of lading in the Hauser archive of MHS indicates that many components of the ten stamp mill were shipped by boat from the Marshall foundry in St. Louis to Fort Benton in April of 1866. This shipment includes 10 stamp heads, 2 battery boxes, flywheel, 12x24 steam engine, etc. The plan was to set up a mill at Argenta, but the equipment was diverted to "Flint" early in 1867 (ann. rpt, 1867 St. Louis and Mt. Mining Co.). The pans and settlers were purchased from the Miner's Foundry in San Francisco (San Francisco Bulletin, March 11, 1867). Larry Hoffman has located a drawing of a somewhat larger 20 stamp silver mill of the same era with apparently identical pans and settlers from the Miner's Foundry.
A later description by W.H. Emmons in USGS Professional Paper 78 says that a Blake jaw crusher was installed ahead of the stamps, and that a "mixing floor", where mercury, salt, and copper sulfate were mixed with the ore, was present between the settling tanks (the rectangular boxes just to the right of the stamps) and the  pans (the smaller, round tanks immediately to the right of the settling tanks). The large area between the battery and the pans in the floor plan below (circa 1889) must have been where the settling tanks and mixing floor were located. The earliest accounts do not mention the crusher so we are unsure of when it was added to the mill. 

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