Grant H. Smith The History of the Comstock Lode 1850-1920, Geology and Mining Series No. 37, University of Nevada Bulletin: Reno, Nevada, vol. XXXVII. 1 July 1943, no. 3, (revised 1966), Ninth printing, 1980. 305 pp., 1881, 1880s, 1870s
[p. 249] Chapter XXV Fire in the Stopes-Low-Grade Operations in the Bonanza Mines-The Comstock Milling Monopoly-The Last Washoe Process Mill-Losses in Tailings-Tailings Reworked
[p. 249] Fire in the Stopes
[p. 249] "The immense quantity of timber used to fill the stopes of the Virginia and the California was often remarked upon: "Every ton of ore extracted from the Con. Virginia and California mines leaves a corresponding vacuum. That space is filled with solid 14- and 16-inch timbers, leaving only a sufficient space between the huge bulkheads for the passage of men and cars . . . The cost of these timbers at the mines is $21 per thousand feet (board feet), but even at these figures, it is much cheaper to fill with timber than to employ men to fill with waste rock."
[p. 249] "Not less than 150,000,000 feet of timber, board measurement, had been packed into those stopes and workings-enough to builld a dozen small cities-and a fire would turn the mines into a volcano. Lord tells of that danger and of the vigilance of Mackay and Fair.
"Fortunately, no fire occurred until May 3, 1881, when the bonanza ore was exhausted. There was no hope of quenching it, so all drifts and other openings into the stopes were closed and sealed in order to shut off the supply of oxygen.