In an Arsenic Mine.

Manawatu Herald, 7 August 1894, Page 3

In an Arsenic Mine.

Many points of interest are brought out in a description in a technical journal of the way in which arsenic is obtained from one of tho most famous mines in England. The arsenical pyrites consist of 25 to 80 per cent of iron, 12£ to 14 per cent of arsenic, and the. rest of earthy matter. After being crushed, this is sorted by girls of from 18 to 10 years of age. It is then washed and "jigged," or sifted, and passed on to the first calciner, where it is burned with low class coal, and produces '• arsenic soot " — that is, arsenic so mixed with smoke soot from the coal as to be of a grey colour. The arseuic and soot, deposited in combination in the chimney or condenser, are scraped out and taken to the second calciner for purification. The calciners consist of revolving iron drums, through which a fire of anthracite coal is carried on rotating iron furnaoes kept red-hot. As the arsenical soot is subjected to the influence of this heat the arsenic is sublimed and condensed. This operation has to be carefully watched, and if the workmen burn the arsenic badly they have to pay for ifc. Three men in four weeks will make 100 tons of arsenic. The chimney in which the arsenic i 3 condensed is a mile long. Ifc is carried to an incline up a hill, with iron doors in the side. As the hot blast passes upwards ifc deposits a crust of arsenic crystals on the brickwork all around to a depth of fiom two to three inches, and a minute dust of crystals falls to the floor. The smoke has then to pass into an npright chimney 125 ft high, but just before doing so it has to traverse a shower of water, which catches what remains of the aisenic, nothing but sulphurous acid being allowed to escape.