Show AIR OI 01 ventilation DOORS IN LARGER ARIZONA COPPER MINES by E D gardner it has las only been in recent years that the proper ventilation of metal mines has received serious consideration in creaser g temperature and humidity with greater depth in some of the larger mines of the west prevented the efficient operation of the mines and made the installation of mechanical ventilation systems necessary doors that interfere with are generally needed to control properly the mechanically induced air currents and are one of the inherent disadvantages of the system in fact the necessity for the use of doors in the main haulage ways has discouraged the installation of mechanical ventilation in some metal mines A number of mining companies in arizona are using ventilation doors which can be opened and shut mechanically by the motorman without leaving his seat or stopping his train and thus interfere very little with the T ck wl r ad of doore for 11 inlet ft ewt air cylinder AM tl iti of I 1 or I 1 too gift do r n tation tion of the ore the copper queen branch of the phelps dodge odge corporation at bisbee introduced these ventilation doors and adapted them from those in use in the com banys coal mine at dawson new mexico 0 other mining companies mp anies have installed the same type of door and it is now ow being used in a number of districts in arizona the doors at the e calumet and arizona mine in the bisbee ri isbee district are representative of those in use the doors ors at this mine are substantially built of 2 inch lumber are air aar tight are well placed and have two openings or passageways eways the main door which is used for the motor trains kalns is 5 feet wide by 6 feet high and is opened by compressed air and closed by a counterweight at the side of the ne motor tor door is the man door which is 18 inches wide by teet feet high and is opened and closed by hand the for opening the main door consists of a section of 5 inch pipe about five feet six inches long threaded beaded at both ends and used as an air cylinder A piston pistol fits ts in ln the he cylinder and is attached to a 1 inch plunger rod box at end of which passes through a stuffing one the w pipe the free end of the rod is attached to a rope that Vs boes over er a pulley and is fastened to the door A 3 sl inch h pipe 1 pe connection from the compressed air line is tapped gitig En engineer gincer U S bureau of mines into the cylinder at the packing end when the air is turned on it forces the piston to the other end of the cylinder and thereby opens the door the door is held open as long as the air pressure is maintained and is closed by the counterweight and the force of the air current when the pressure is released the air is turned into the cylinder from the main air line through a three way cock levers placed at some distance from and on either side of the door are connected to the air cock by two wires when a train approaches the door the motorman reaches out and pulls the first lever this opens the cock turns the air into the cylinder and opens the door after the train has passed through the door the motorman pulls the lever on the other side which shuts off the air releases the pressure in the cylinder and the door is closed the motorman on a train coming from the opposite direction would pull the same levers but in reverse order as these are so arranged that the doors are opened or closed by pulling the levers in the direction of the moving train the distance that the levers are placed from the door depends upon the length and speed of the trains but should be long enough to give the motorman time to stop his train before it wrecks the door if the mechanism failed to work at the calumet and arizona mine the distance is feet A red light is generally placed at each lever and other safety precautions taken some doors have been demolished in some of the mines by trains striking them but with ordinary care on the part of the motorman the use of the doors is safe and no accidents should occur none of the doors have been touched by trains in the calumet and arizona mine for a number of years the magma copper co at superior arizona uses a modification of the same door in the main haulage level As no supplemental man doors are used the danger of a man being struck when the doors are opened was obvious and whistles which start to blow as soon as the air pressure is turned on were placed in the air cylinders and give warning to all in the vicinity the whistles also continue to blow as long as the doors are open and remind all in that part of the mine to release the air the accompanying sketch shows the general construction of the doors at the calumet and arizona mine |