File:Bulletin (1910) (14590103340).jpg

Identifier: bulletin154unit (find matches)
Title: Bulletin
Year: 1910 (1910s)
Authors: United States. Bureau of Mines
Subjects: Mines and mineral resources Mines and mineral resources Mining engineering
Publisher: Washington U.S. Govt. Print. Off. (etc.)
Contributing Library: Gerstein - University of Toronto
Digitizing Sponsor: University of Toronto

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100.0 4.05 100.00 C. SAMPLES TAKEN FROM BOTTOM OF PILE. 3 6.680 0.263 12.9 2.2 13.1 10 1.651 .065 56.25 2.3 .59.4 35 .833 .0328 12.1 1.7 9.45 200 .074 .0029 14.45 L8 11.95 <200Total .074 .0029 4.3 3.1 6.1 100.00 2.17 100.00 Table .45.—Screen analysis of representative sample taken from, tailing pile in Galena district. Size ofmesh. Size of screen openings. Percentageof weight. Zinc assay,per cent. Percentage of total zinc. Mm. Inch. 3 10 35 200 <200 Total 6.6801.651.833.074.074 or average... 0.263.065.0328.0029.0029 22.9548.710.514.6.53.2 2.02.22.53.64.3 18.6543.610.721.455.6 100.00 2.45 100.00 Table 46. -Screen analysis of representative sample taken from, tailing pile in Prosperitydistrict. Size ofmesh. Size of screen openings. Percentageof weight. ZLnc as.say,per cent. Percentage of total zinc. Mm. Inch. 3 10 35 200 <200 Total 6.6801.651.833.074.074 or average... 0.263.065.0328.0029.0029 24.745.212.1514.93.05 0.9 .9 .4 LO 2.2 24.945.5 5.4516.7 7.45 100.00 j 0.89 1 100.00
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MINING AND MILLING OF LEAD AND ZINC ORES. 117 LABOR CONDITIONS. Nearly all the miners and surface men in the Jophn district areAmerican born. As a rule they are efficient and intelligent, andreadily pick up new ideas whenever they are given the opportunity. The shift for underground work in the mines is 8 hours, whereasthe mill shifts are 10 hours each. When a mine has been welldeveloped a single underground shift can often break enough ore tokeep the null running during two 10-hour shifts. A few of the largercompanies are now running their mills thi-ee 8-hour shifts ratherthan two 10-hour sliifts. It is beheved that this plan, if followed,will in many cases make for greater efficiency ui both mining andmilling. In 1916 the average scale of wages paid to the miners in thisdistrict was based on a sliding-scale basis of a 25-cent increase ordecrease for every SIO increase or decrease in the average base pricefor 60 per cent zinc concentrates covering a period of one month.The following

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