Show HOISTING WITH compressed AIR A special from butte montana to the boston commercial contains the following interesting account of the application of compressed air for hoisting purposes the experimental stage of hoisting ore by the compressed air plant operated by electricity brought in by a pole line from great falls a distance of miles has passed and the plant is now operating as aa smoothly as the most sanguine could expect at an immense elpe expense nse the anaconda company nearly two years ago commenced preparations for the installation of this plant the pole line for carrying the electricity from great falls to this city was started and about the same time the order was given for the machinery while the construction st of the necessary buildings for the plant was commenced soon after last july the buildings were completed and the rna machinery chinery commenced to arrive A little over two months ago the mountain view mine was closed down for the pur purpose lose of equipping the engine with the new cylinders required and today everything is working with the regularity of a bloc clock k bedfor the actual hoisting of ore was commenced experimental work was carried on oil for more than a week to make sure that there would not be the slightest hitch when the ore was loaded the mountain view is today bringing to the surface from 1000 1000 to 1200 tons toils of ore a day by the air plant operated by electricity while compressed air has been used to a very limited extent for hoisting purposes the anaconda company enjoys the distinction of being the first big mining company in america to operate the system on such a large scale some people had little faith in the successful working of the new system but the officials of anaconda company and the installing company never had any doubt as to its success the plant consists of three direct connected variable capacity air compressors each with a capacity of cubic feet of free air per minute when operated at full capacity horse power is required to drive these compressors they are of the latest type design they are of the most efficient compressors the company has ever constructed and have both high and low pressure cylinders they are self starting and start as a compound engine the air first entering n the high pressure cylinder from which it is exhausted into the low pressure cylinder and from the low pressure it is exhausted into the atmosphere when the compressor attains its normal speed the current is thrown on the valve gear is reversed and the machine is at once converted into an air compressor the fly wheel of each of the three compressors pres sors is 25 feet in diameter and weighs 25 tons it is keyed on to the main shafa which is 22 inches in diameter and weighs 11 14 1 1 tons it is direct driven by a motor the fly wheels making 75 revolutions a minute piston rods extend through the cylinders and travel on tail carriers which relieve the bottoms of the cylinders from pressure and consequent friction the com pies sors sors are provided with an automatic system of oiling in the process of compression the air is cooled between the low and high 3 pressure cylinders the cylinders being water jacketed the water for the cooling jackets is received from a tower some distance away from the compressor com room on an all elevation where it is cooled by means of electrically driven fans there is no doubt the whole plant is the most extensive of its kind ever constructed and the fact that it has been put into commission after a few preliminary tests is a source of great gratification not only to the builders but to the officials of the company |