Journal - South African Institute of Mining and Metallurgy . rom 68 . Maximum quantity ofur supplyin cub. ft. per minute. Minimumquanl ii y ofair supplyin cub. minute. Diurnal variation, in cub. fi. perminute. Percentagediurnalvariation from nightto day. 16 5 (57 1 93 24 9 50,000 23,000 27,000 54% less 17 9 55 1 93 Ll 11 50,000 27,000 l3,000 46 „ is 3 80 0 100 23 12 18,000 29,000 19,000 10 .. 19 0 100 0 100 20 16 43,000 36,000 7,000 16 „ 20 0 L00 0 100 22 20 17,000 13,000 9 „ 21 7 62 0 100 22 14 47,000 32,000 15,000 32 „ 22 8 D8 0 100 28 15 57,000 34,000 23,000 40 „ 23 11 17 1 71
Journal - South African Institute of Mining and Metallurgy . rom 68 . Maximum quantity ofur supplyin cub. ft. per minute. Minimumquanl ii y ofair supplyin cub. minute. Diurnal variation, in cub. fi. perminute. Percentagediurnalvariation from nightto day. 16 5 (57 1 93 24 9 50,000 23,000 27,000 54% less 17 9 55 1 93 Ll 11 50,000 27,000 l3,000 46 „ is 3 80 0 100 23 12 18,000 29,000 19,000 10 .. 19 0 100 0 100 20 16 43,000 36,000 7,000 16 „ 20 0 L00 0 100 22 20 17,000 13,000 9 „ 21 7 62 0 100 22 14 47,000 32,000 15,000 32 „ 22 8 D8 0 100 28 15 57,000 34,000 23,000 40 „ 23 11 17 1 71 29 IS 5.), 000 40,000 r.»,ooo 32 „ 24 19 30 1 92 26 15 54,000 •11,000 2 o,000 37 „ 25 18 32 3 SO 25 13 5l,000 30,000 LL, 000 42 „ 26 Ll 28 0 100 LL 11 27,000 20,000 42 ?J 7 14 13 7 59 21 7-5 45,000 l0,000 25,000 •• „ 28 15 Ki 3 80 19 9-5 41,000 Ll,000 17,000 41 „ 29 15 to 3 80 20 7 4:5,00(1 23,500 55 „ 30 i6m 38 1 1 93 18 m) 40,000 47 .. Nov. Km: .hi,a* Moi\ Voteon tfu Daily Variation of Rand M A I. y - /. T / 2 / = f. 14(1 The Journal of The Chemical, Metallurgical and Mining Society of South Africa. Nov. 190 It will be seen that the maximum quantity ofair in the whole period was 59,000 (which is much the same as the maximum observed in 190 1),but it is probable (from the fart that the lowest temperature observed was 39°) that in thecoldest snap of the year, which would beabout 32 F. wet-bulb, the ventilation will nowrise to 70,000 cub. ft. per minute. The minimum observed was 19,500 this time(in 1904 it was ), corresponding roughlywith the general improvement due to the increasedsize of workings. 1 do not know exactly howmany workers are underground at any one time—perhaps Mr. Mitchell will oblige—but assuming650, this gives 30 cub. ft. per man per minute,the maximum being about 100 cub. ft. per man. In addition the daily averages and the totalaverage have been obtained by the use i f the plani-meter on the c
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