Show karns beadi heading ng machine at bi bingham engham BY ay iy L GILBERT mining men will be glad to learn that the J P karns tunneling machine has been under development for the past ten years has at last reached a point of commercial success the utah karns tunneling LIN machine Tachine company which owns the right to operate the machines in the state of utah on a royalty basis has a karns heading macii maccine ine in operation on a contract for the montana bing ham mining company at bingham utah and the work of the machine has demonstrated that it is all that has been claimed for f or it the tunnel which is seven hy by seven feet is through typical bingham and has been driven about feet with tho the machine which shows no sign of weakness and does its part of the work with remarkable ease and rapidity enlargement of air drill principle the machine is simply an enlargement of the air drill principle cutting abole ahole a hole thirteen inches in diameter the head is faded faced with six sets of cutters these are bars of steel one and a fourth inches thick and five inches wide which drop into a grove at the head of the machine the cutting edge is notched and so divided into sections or bits and the bits are sharpened and tempered the same as the bits of an ordinary drill the six sets carry twenty six to twenty eight such cutting points they are easily replaced when dull and easily sharpened by the mine blacksmith one set cuts the entire fifteen feet without sharpening or changing the head is forged on the end of a four inch shaft which travels through a ball bearing jacket or shell the latter rides on small rollers on the frame of the machine and follows in on the bottom of the hole as it is cut in this way as much of the friction is overcome as is possible and as the head is equipped with a set of cimmers which enlarge the hole one half inch more than the diameter of the head there is no binding in the action of the machine rand piston cylinder the header is driven by a five and a half inch rand piston cylinder taken from stock and the action is that of the piston drill a straight stroke against the rock with a turn on the back stroke the rand drill com banys rating on this cylinder is cubic feet of air but it seldom requires the full head which means that the ordinary mine has power enough to operate it the frame is mounted on trucks and run up to the breast and fastened to the track much quicker than the ordinary drill can be mounted the thirteen inch hole is then driven in a distance of afif fifteen teen feet while th this is is being done the small drills are putting in the small holes the first of these is driven parallel to the big hole eighteen inches above and the second below it when these two are shot they break into the thirteen inch hole the result is a cut four feet high thirteen inches wide and fifteen feet deep the rest is simply a matter of drilling and off the balance of the tunnel to the desired size ten small holes are drilled in this tunnel ten small holes are drilled in all and the entire round is broken at one shooting for a distance of fifteen feet one hundred pounds of powder is required which is a saving of about 40 a day in powder alone added to this is the saving of running the compressor only about six hours out of the twenty four after af ter the round is shot the next two s shifts are devoted to removing the muck laying track and preparing for the next round of drilling two machine drills are used for the small holes which materially reduces the cost in machine men the header has never required more than three hours for driving the full fifteen feet and on occasion has driven it in less than two hours the entire round is drilled in from tour four to five hours in brief the machine has demonstrated that with it fifteen feet of tunnel can be broken in one eight hour shift at a saving of about working under adverse conditions the work was started under most adverse conditions the haul for the muck is over feet and as there is no trolley or ivator n aror oror it has to be handled with mules 1 acre is not a siding the entire distance anich is a serious drawback the tunnel is very pry wet retarding progress and making it difficult to keep good men other interests re ie using tile the same air line and track and this also sometimes causes considerable sid erable delay when the work was started the company happened to 0 o get a supply of poor fuse this caused considerable delay and resulted in the trial of a battery and electric fuse with unsatisfactory results A good grade was secured later since which time good progress has been made during the week preceding the writing of this article the contractors who were removing the muck fell down on their end of the work this caused the loss of two days time new laborers were secured and during the balance of the week more than seventy feet of tunnel was completed A great deal of interest is displayed in the machine in the district the company has arranged for another piece of tunneling work on which will be commenced as soon as the present contract is finished many inquiries regarding the header are coming in and there will undoubtedly be several of the machines in operation in bingham and vicinity in the near future it is learned that mr karns has recently applied for patent on a mechanical designed to greatly increase the speed of the heading machine plans are also under way for the manufacture of a six foot machine to work on the same principle as the present machine which has been demonstrated to be entirely practical |