Show driving dri vi ng the LJ V X extraction extracts Extrac ti on tunnel BY I 1 D J the potter construction company railway leeway exchange building st louis is daiv jing abling an extraction tunnel for the united at avi Verde erde extension mining company of jerome arizona arizona the object of this tunnel is to simplify the present system of handling ore from the audrey and edith shafts at present the ore is dropped feet down the mountainside on an aerial tramway into storage bins thence it is reloaded in cars of standard gauge on which it is hauled a distance of about three miles over the U supt bupt potter construction co clarkdale Clark dale arizona this article is reproduced from mine and quarry for february cuts furnished by courtesy of the sullivan machinery company chicago V T S R R after which the cars are transferred to the santa fe system to be hauled to douglas or humboldt this tunnel which is feet in length will not only save this long haul and of ore but it will save hoisting the ore 1100 feet f e et from the thirteenth level of the united verde extension main shaft the ore will be shipped when this tunnel is completed direct from the foot of the main shaft where pockets are to be constructed for storage purposes through the tunnel onto the arizona Ei extension tension railroad on which the cars will be hauled direct to the new smelter about three miles distant the course of the tunnel from the united verde extension main shaft to the portal which is about a mile and a half northwest of clarkdale Clark dale and two miles and a half from the mine is As shown on the accompanying plat the grade of the tunnel is downhill down hill from the mine per er cent or feet drop per mile the tunnel is being driven eleven feet wide at ten feet three inches wide at the spring line and ten and one half feet high from the completed tunnel will give a clearance nine and one half feet high above the permanent rails to the top of the arch A ditch eighteen inches wide and one foot deep is carried at the side of the tunnel for drainage the tunnel 1 ne l will be laid with seventy pound rails 4 I 1 N za A 7 B 4 4 46 ca X Y sullivan DR 6 drills on an columns in the portal heading of the U V X extraction tunnel jerome arizona the heading crew includes expert Drill drillman men who have helped make progress records on well known tunnels in other parts of the country ala abild the track will wilye 64 standard railroad gauge the roadbed ni 1 I I 1 na nhe built to carry steil steel fIl cars with hop b J bottoms toms having t thirty t 0 AX built especially for wit this merya r i e haul baula adwill ff Swill be by I 1 electric locomotive and trolleys trolley troll el 3 the tunnel is being driven from four headings that is from inside the mine from strata in the portal end conglomerate was immediately encountered and at the time of writing at which this heading has been advanced approximately feet the conglomerate is still the prevailing formation this conglomerate is an exceedingly solidly compacted mass in fact so tight that thus far no water at all has been encountered which required heavy timbering it if th ahw dykes had been encountered at right lit a anali they could have been supported by one olie i two sets of timbers but due to the ad ane at which the heading crossed them thein jitt it fi required ten to twelve sets be t B to cati cat t them up timbers used for this work vei spaced on five foot centers A 91 J ta 71 agn head frame dump and yard at texas shaft U V X 8 tunnel it 1 1 of these dykes or faults greatly re retarded progress the most interesting part of the wor work k geologically speaking was enc encountered ive ac in sinking the texas shaft this was 7 sunk at a point which it shortly developed r was on a well defined fault the geologists ee e e Z P at the mine predicted that limestone would in the heading the body of the the conglomerate be encountered at a depth of about feet consists of eroded limestone which acts as all indications of beds 2 UL outcrops stream stream as a natural cement to hold together frag etc in the vicinity indicated this would be 2 2 the case the shaft first ran into the con 3 1 C ELEVATION PAC amr COPPER CO af naus N COM cross section of U V X E extract x tion mine PASO tunnel anne les at jero me arizona arizona S showing howing line of 0 tunnel jl A j station heading drill round U V X tunnel the outside or portal end and from both headings at the foot of a shaft which has been sunk at a point feet from the portal this is known as the texas shaft it is feet in depth and consists of two hoisting and pumping compartments feet and a manway feet geology the formation through which the tunnel is being driven represents a variety of apparently parent ly unsystematically placed geological of small pebbles up to blocks of stone three feet in diameter and this material includes sandstone limestone and also igneous rocks such as diorite and the lava rock locally known as ma malapas mal apai lapal which is very dense and difficult to drill the difficulty of drilling this formation will be readily understood by those familiar with rock conditions at the station end of the tunnel where the heading has been driven about 1350 feet the first rock encountered was diorite and schist due to the proximity of this heading to the mineralized zone of the mine the formation was badly cut up with diagonal dykes of soft material similar to ca calcite eclie or soapstone 4 which is the usual capping rods rock of the vicinity after running through this for about fifty feet boulders of basalt were struck and a little below the shaft encountered solid basalt rock much of this was of 4 a red color resulting from the hematite bonding of the material it did not lie in any well defined beds but stood on edge in irregular masses jointed and blocky after penetrating this material for about feet the quartz porphyry was encountered in ill a badly broken up condition for a distance of about feet from this point piles had bad to be driven outside of the timbering to hold the ground at about feet or some thirty five feet from the bottom of the shaft which is feet deep the soft oxidized porphyry altered to hard solid quartz por phyra and the crosscut was turned in this material and driven fifty feet from the foot of the shaft to the intersection with the tunnel line driving the portal heading the portal heading was started on july 7 1917 the footage driven since that date has been as follows july feet august feet september feet AM 7 V IN portal of U V X tunnel D J at left two of the 14 foot drills used are shown at right october feet november feet december feet january feet this makes a total of feet or an average of feet per month W J eo texas shaft U V X tunnel engineer at left D J at right considerable delay was encountered in making satisfactory progress in this ground at the start due to the difficulty of getting holes to depth in the formation the first method of 0 drilling tried was by means of self rotating hammer drills holding the machines by hand for some holes while for others the drills were mounted on cradles and feed screws on columns four drills were used in the heading at one time and holes eight to ten feet deep were drilled S seven even eighth inch s hexagon hollow steel was used with cross bits the drills were of the water type by means of which a water and air jet was forced to the bottom of the drill hole to clean it of its cuttings after driving ninety or feet with the rotators it became evident that the use of mounted drills entirely would give better satisfaction on account of the difficulty in keeping the holes in line when running through the uneven formation it was also decided to substitute heavier machines for the rotators and the sullivan DR 6 water jet mounted hammer drills with 2 inch cylinder and weighing pounds were adopted for a considerable period the 1 V 1 R p ney V 0 it cullivan angle compound Corn Dressor used for operating the drills portal heading U V X tunnel heading was advanced with two DR 6 drills mounted on double screw mining columns the drills being carried by means of extension arms enabling the drill to work thirty six inches from the column in drilling the side holes to follow the contour of the tunnel deep holes drilled with DR 68 it has later decided to increase the depth of the holes from ten to thirteen feet and a third drill was added to advance the rate of progress the advantage of using holes of such 44 great depth for the cut is demonstrated by the success with which the ground was pulled after the change was made six cut holes are used the solidity of the bonding of this c conglomerate on material will be shown by the fact that with the thirteen foot cut holes seven or eight feet of the cut are of often ten thrown out by the first shot in a practically solid mass of wedge shape requiring re blasting before it can be mucked the cut holes are then loaded again and deshot before the side round is fired if any of the cut is still left after the second shooting it is again loaded and shot with the side round the explosive used in the cut holes which gives excellent satisfaction is atlas blasting gelatine of 60 per cent strength atlas gelatine of 40 per cent strength is used to blast the side rounds and roof holes the side round and roof holes are fired at the same time delay exploders explode rs being used for the roof which is thus thrown out after the side round has gone no relieving holes are used as it was found that the heavy charging of the cut holes occasionally caused ignition of the charge in the relievers at times when seams were being crossed four rib holes are put in on each side of the tunnel four holes in the roof and four lifters making a total round of twenty two holes the roof and side holes are of approximately the same depth as the cut holes T this his tunnel is now being driven as indicated by the sketch page 24 by the top heading and bench method the work being divided between a seven foot heading and a three and one half foot bench the bench is is kept within about thirty feet of the heading at all times and is drilled with sullivan DP 33 water tube rotator drills using as inch hexagon hollow steel with cross bits holes are drilled with these machines to a depth of about five feet to insure reaching the of the tunnel disposal of muck telescopic bars or braces are placed across the tunnel just above the grade of the bench dt at a sufficient height to permit the tunnel cars to run below them planks are laid on these supports serving as a runway for the barrows in which the muckers duckers remove the material from the heading and from which it is dumped into the muck cars below the bench muck is shoveled direct into the cars the tunnel is laid with double track of twelve pound rail at the heading the switch being moved forward every two weeks and passing tracks are installed about 1200 feet apart steel side dump cars having a capacity of thirty two cubic feet are employed for handling the muck these are the same type and size of cars as those used on the los angeles water works tunnel some five or six years ago mule haulage is used the mules aerated by a single man drill the bench the next or night mucking shift comes on at 8 in the evening and the miners again dt at 11 rate of progress As will be noted above the monthly progress including the short month in july has averaged better than feet during the month of december feet were driven with the length of holes finally used it has been not at all unusual to secure a progress of twenty five feet of heading in twenty four hours two shifts fifty eight shifts were worked during december to give the progress mentioned above station heading As stated above about 1350 feet have been driven from the inside or station end of the tunnel the problem at this heading 4 tvr CM VMS ra ak air 4 ita ir blacksmith shop of potter construction co at portal heading sullivan drill sharpener at left oil forge in center tempering tank at extreme right coming right up to the end of the scaffolding which is within thirty or forty feet of the bench so that practically no hand is necessary one mule hauls two cars at a time organization and working plan two eight hour shifts are worked the mucking gang consisting of twelve muckers duckers and a foreman commence work at 8 a in three hours are required to load out the muck from the previous shot at the face of the heading so that when the miners come to work at 11 they are able to set up the columns and start drilling the new round two men are used on each machine in the heading under favorable conditions the heading round is completed by or 4 and the round is then shot so that ample time is allowed between shifts for blowing the smoke two rotators each op was not one of drilling speed but of adapting the work of organization to the organization of the mine As described above in all about feet of timbers had to be set this was a costly operation as weaknesses in the rock frequently developed after they had been passed for some distance and it was necessary to delay operations until the weak spot could be widened out and the timbers set all muck from this heading has to be handled through the main hoisting shaft of the united verde extension mine or br carried back into empty the cars are h handled Y by tail rope haulage trouble was also experienced in blowing out the tunnel after blasting so that special means for ventilation had to be devised F finally it became necessary to draw a fresh air supply y from the edith shaft on the thirteenth level by means of twelve inch pipe the exhaust system being used to suck the air in from the edith shaft by a no 8 buffalo blower due to the conditions mentioned above it was found that a rate of advance of between five and six feet per shift was as great as proper disposal of the muck would t allow the sketch page 24 shows the tun L nel round in this heading which is practically the same as that at the portal heading except that relieving holes are used to se cure better distribution of the powder andl and break up the muck smaller two sullivan DR 6 drills mounted on extension arms on double screw mining columns are used inthis heading also for drilling the heading round the bench is drilled by means of lifter lif ter or horizontal holes put in from a cross bar by the heading crew after they have drilled the heading round the DR 6 drills are mounted on a bar for this purpose and seven foot holes are the rule the bench is carried up to within a few feet of the heading and all muck from the heading thrown over the bench the material from the heading and bench both is loaded directly into the mine cars sinking the shaft the shaft described above feet in depth and feet in area was sunk entirely with sullivan water tube rotators of which four were employed pressure for the water jet was obtained by gravity from 0 a sump at the foot level and from the surface down to that point in sinking the shaft holes were ordinarily drilled to a depth of seven feet it was necessary to carry the timber quite close as the work progressed and under ordinary conditions about one set of timber was placed per day on 5 foot centers the round of holes averaged sixteen and these holes were shot electrically with three sets of delay explode ers the cut holes being fired first then the first set of side holes and so on this method of shooting was entirely satisfactory and much safer and more reliable than fuse which was tried at first work on the shaft was started june with a hand windlass on july operations were commenced with a hoist and head frame which had been erected over the shaft the hoisting engine was furnished by the mining company one foot compartment is used for hoisting the second for pumping and the third W 2 5 feet is used as a manway water was encountered at a depth of about feet from the surface and gave considerable trouble A station had to |