| Show long hole drilling cl ll aul at the gerh eagle al pue and blue ilag bell property of lo the alp bingham mines company i in U gintic dillu district by aa I 1 cl billings im mining engineer constantly increasing costs of jo operating the past maj few years SIEDS have necessitated the replacement of jo many plo old established I 1 methods al with ill newer I 1 more pup efficient juz pui and less eppen asive DAIS M ways S of JO carrying on mine ouica exploration and p development jua one of the most ism important results of jo this condition has been tb development taip of JO long I 1 hole aj drilling for several years MD s the QT mining companies of jo butte aling experimented ua in this direction and while their experiments were not IOU entirely satisfactory they nevertheless LUp demonstrated the eid practicability eap of jo the idea pue and indicated the pronounced p saving that could thus be effected in u lu mining au operations basing their efforts on the experience au of jo those butte alina companies c the chief ll jT consolidated mining company of jo yeureka jE ureka am began a campaign of jo long hole prospecting during the latter awe part of JO 1923 pue and m in collaboration with the den beirock yei la Rock cl drill I 1 company designed and perfected suitable equipment using the all latter companas comp v anys J mod powerful f gnp Tur iq bro o ack alp ilp drills 0 e obtained were dmm so Os satisfactory that the eagle af a 6 alue alq bell mining company whose property adjoins at jo of the PRID chief adopted zap the method JM early ul in 1924 and has bosn 11 ll most continuously for the d past isu six months lAl method por proves SA especially adapted to ol gintic tintic iaia LU method seems aws especially adapted to 01 conditions pre aid ln ul in the L gintic tintic ua mining district where the irregular currence of jo io ore bodies sl necessitates the thorough prospect au ot jo aj the entire mineralized area when this st is done by 0 aleu ap pp drifts crosscuts cross cuts raises and dinzes the ISO o v 1 largely ap xa limits the all work whereas st the qa new aiu method uvo can on at an incomparably lower imol cost assuring max anum alt satisfactory 0 x results per dollar expended emphasize the conditions under which the long hole IOU nethal y be used to 01 advantage a brief description of jo e z 10 of 31 c 3 editions at the eagle 22 blue bell property may kew C ali IOU L t mation entirely of jo exposed on surface consists nedime gelnn Clua t XI y rocks axa except oj for certain minor PU nd m U gardner limestone series C at 4 the north 0 of al v Z c all 11 the ore deposits ell have OA been found ard 72 rin I 1 sl known su as th ip blue ale bell dolomite which st is a defined aug ed rock ioa about feet thick al two alorth soua 1 11 lerse mala DS this dolomite trending d practically zal oDIo ore sinz TS si as replacement deposits ut in the I 1 au s i pain ore k owin assures or io i faults besides on the sal g ssu fissures sin ore bodies have been formed on je ila e J lye B thereto adaily e a a with ore aio deposits UT limestone can 11 estand p how easily janjua valuable iq ore aio bodies can q be sq b y exploratory crosscuts cross cuts t raises pue and dinzes made only on promising indications the atu whole amm problem may be summarized st as the zal necessity of doing the greatest mia asal possible amount of jo prospecting pue and development commensurate L with ore returns and the long hole method seems to 01 offer the best solution drills operate at any adv angle PUL and moi low cost under aj this s method p jj the n equipment can be set up pui and holes drilled in ul SUL any direction from ZAU five degrees above oal DA the qa horizontal juju to 01 AU five degrees from vertical the al saving ul in time si is empty indicated pal by the ej fact jo that ivri su as much su as SZ 78 feet seq has been ip drilled pall q by two omi men on an eight hour shift the average cost for boj a e total of jo 2344 feet so os far drilled is si per md foot W af N A t V work on igo the alp 1000 foot level at u equipment long hole drilling la alimi of 10 the lilla bugle ap 3 blue bell mine hallm utah the aj longest hole drilled up to ol this sly time is COZ feet put and encountered has been the failure Z to 01 drill the qa only difficulty through udo open or io boulder filled sij fissures sains eagle p onlee blue bell equipment described the equipment wa used by the qa va eagle W blue bell consists of jo a model botu potu p 0 34 f waugh aaa independent rotation aop Tur bro rock poi pounds and having a four inch piston drill weighing between hammer this drill is si mounted on a double headed arm two three inch columns the drill rods are of 11 1 PUT inch round puno 1 hollow steel in U 3 1 6 9 and r pu 9 6 foot lengths with straight i double thread itil forged on each tua end these rods SE as special steel pals sleeve A used ui in connecting them were well as S a especially designed by the denver 1 rock drill III company which also developed special equipment for forging the thread and collar the cutting end of the steel consists of double taper cross bits slightly reamed at the center ranging in size from 31 t inches used in beginning a ho hole le down to inches 1 1 water is forced through the drill rods to the cutting end at high pressure by a small air operated feed pump because of this high pressure it is found necessary to introduce the water directly into the rod rather than through the drill as is ordinarily done and for this purpose a special water connection swivel has been designed which is fitted on a sleeve connecting the shank rod with the drill rod the total cost of the equipment was 1 in operation the cuttings from each hole are c caught aught in a box and every six feet these cuttings are assayed however regardless of whether the assay shows metal contents or not if quartz is noted in quantity a development crosscut is made as local experience has proved the proximity of ore to quartz two ore bodies are disclosed so far this work has resulted in the disclosure of tac ore bodies which are now being developed the first discovery was made through hole no gi 22 which encountered lead silver ore at the 78 foot point th chii 1 hole was drilled at an angle of 30 degrees above hori horizon zonta tf 51 after a number of holes at five degrees above horizone hori zonta from the same set up had failed to show even promising promis inc indications in making the second discovery the first hole drilla at five degrees above horizontal encountered low grade qt quartz jartz at foot point A crosscut was subsequently made and development to date has exposed a valuable ore ort body 60 feet long averaging six feet thick v in kiev of results already obtained the company feel that this method offers an invaluable opportunity for oper acors to offset to some extent the handicap of present ris in ing costs |
