Show DEEP DRILLING IN SOUTH AFRICA diamond drilling as a means of locating I 1 the gold bearing reefs of the transvaal has been in general practice for many years unusual interest attaches to it at the present time owing to the large number of deep holes boles which are being sunk to prove the existence and position ot of the ore bodies at increasing distances from the outcrop for this work larger and larger drills have been used and within the past year or two numerous bore holes have been bottomed in ore at depths of from to feet upward of diamond drills are now in use in south africa the prevailing types being the sullivan and bullock manufactured by the sullivan machinery company of chicago for the deep holes referred to the favorite drill is the sullivan improved class P rated capacity feet the 4 DEEP DRILLING IN SOUTH AFRICA mining companies as a rule let the work to contractors who furnish all the equipment and expert operators and deliver the core into the hands of the company american contractors have recently broken all records for depth james tobin completed a bore hole last december at sixteen miles west of Rand fontein at a depth of feet this hole was sunk to prove the main reef series and it is understood that the results are conclusive I 1 although they have not been made public the deflection was very slight the first feet were bored with a sullivan size N drill rated capacity 2000 feet A size P drill of latest improved pattern with rated capacity of feet was then put in commission and continued the hole until its completion at feet seven hundred feet of size N rods removing 2 core were used the remaining feet being B removing a 1 inch core the total load of these rods was wa s between fifteen and sixteen tons which was handled by the engine without difficulty the actual running time of this hole was fourteen months or an average of nearly feet per month for the first two months two ten hour shifts were used and for the balance of the time the work was carried on the whole twenty four hours divided into three eight hour shifts the rods were pulled in lengths of fifty feet the heights of the tubular steel derrick being sixty six feet all over the time required to lower the rods at a depth of feet was from three to three and a half hours and from three and a half to four hours was required to lif lift t them this record has since been bettered by a hole sunk near springs east of johannesburg by john this hole was begun may 1 1904 and completed february 2 1905 at a depth depth of feet A size P drill was also used here power being supplied by a 30 horsepower boiler one thousand feet of N 2 inch core rods were used the remainder of the equipment being similar to that used by tobin |