A Study of Coal Mine Haulage in Illinois Volume 132 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1922 Excerpt: ...of 4 hours 43 minutes before proceeding from the cut-off point to the empty-storage track. 19. Shaft Bottoms for Skip Hoisting.--Prior to 1917 there were in Illinois only three installations at which skip hoists were used. Two of these were at small-capacity mines and the end-gate type of car was used; the third mine had an average daily production of between three and four thousand tons and a bottom-dump car was used. Since 1918 there have been opened several large shaft mines in which skips, rotary dumps, and solid-end cars are installed. The capacity of these skips is between 10 and 12 tons. At one of the mines noted, a trial record of 1000 tons in one hour was obtained in 1920. The rotary dump permits the use of the solid-end car, thus giving a more rigid construction, one of the greatest sources of trouble in mine-car construction being the loose end-gate; it also simplifies track layout as the car may be run in either direction. Thus, at one mine the track layout is such that the position of a car on alternate trips from the shaft bottom to the face is reversed, which could not be the case with the ordinary self-dumping cage layout. A detailed discussion of skip hoisting will be found in an article by Allen and G-arcia in the Trans. Am. Inst. Min. & Met. Engr. for 1921. reprinted in "Coal Age," March 17 and 24, 1921. The average shaft bottom arrangements for several mines at which skips are used are shown in Fig. 20. As all these mines are still in the development stage, costs per ton for handling coal on the bottom are not yet available. The locomotives coming to the shaft bottom are detached from their trips at points a, passing thence into the empty-return entries, while the loaded cars move toward the main shaft under control of a pu...