Planks, TABLE X. Flume four feet wide, three feet deep; twelve-foot box. 2 inches thick, 12 feet long. =240 feet b.m. Flume seven feet wide, four feet deep; twelve-foot box. 11⁄2 inches thick, 12 feet long... Planks, =270 feet b.m. Bracket Flume. A novel method of carrying flumes along the face of precipitous cliffs has been designed by W. H. Bellows and adopted on the line of the Miocene Mining Company's ditch in Butte County, to avoid the construction of a trestle-work one hundred and eighty-six feet high. The line of ditch was run some two hundred yards up the cañon, abutting against a perpendicular wall of basaltic rock, along the face of which, one hundred and eighteen feet above the bed of the ravine and two hundred and thirty-two feet below the top of the cliff, the flume was carried on brackets for a distance of four hundred and eighty-six feet. Fig. 16 gives a general view, and Fig. 17 shows the method of hanging the flume. The brackets are made of T-rails of thirty-pound railroad iron bent into the form of an L. The longer arm. ten feet long, is placed horizontally (for the bed of the flume to rest on), with its end supported in a hole drilled in the rock. The shorter arm, two feet long, stands vertically and has at its upper end an eye into which hooks a suspender of three-fourth-inch round iron, which in turn is fastened above to the rock by means of a ringbolt soldered into a hole drilled for the purpose. The brackets are set eight feet apart, and were tested to sustain a weight of fourteen and one-half tons. The flume is four feet wide and three feet deep, inside measurements, and has a capacity of 3,000 miner's inches. The general view shows a trestle eighty-six feet high. Along the line of the ditch there is a trestle one thousand and eighty-eight feet long and eighty feet high; another has been built one hundred and thirty-six feet high. The total length of ditch and flume is thirty-three and onethird miles. Details and Costs of Milton Ditch and Flumes. --The following official statement shows the details and cost of construction of the Milton ditch and flumes from Eureka to Milton Dam. Built by the North Bloomfield Gold-Mining Company in the years of 1872-3-4. measured from head of Eureka drop-off to Milton dam. Flumes. Eureka to South Fork ... =102,484 feet, Total ... 2.338 twelve-foot boxes say, 28,056 feet. The above 2,338 boxes include 56 boxes of flume built in the ditch, most of which is supported by heavy cribbing. |