Daily Arizona silver belt., 1908-08-12
PROSPECTING WITH
 CHURN DRILLS
Continued from Page Thresl

\Continueu rom rage IhreeJ
 in striking eaving or bouldery ground below hard compact stratum, below which the driller often takes the risk of abandoning casing and making the hole smaller. If boulder falls in above the bit, wedging itfi n "spud' v is used to loosen it. This tool is cylin- drical and larger than the drill shank and has its lower end cutting edge. 1t is lowered by steel cable and given a ehurning motion which cuts and breaks up the obstruc tion and loosens the bit. Another annoyance caused solely by the carelessness of the driller is "sanding in. The "spudo is again used to loosen the bit. The jars sometimes lock and stick the string of tools. In such instances the tool called the jar bumper" is used to disodge them. Incidents of rope breaking are common especially in pulling casing. To recover the rope the rope spear is used Often tools are lost, no expedient be ing found to recover them.
 "With respect to recording data, q few points should receive special at tention. The samples of cuttings should be taken every foot all the way down These cuttings should be carefully pre- served in bottles or jugs labeled with their depth and character. A written log should also be kept graphically | showing the formations through which the drill passed. The samples should be taken from the surface down as | carefully as from lower depth, as often a body of shallow galena or zinc | siicate is penetrated without the drill CT being aware of it, the deposit being found when shaft is sunk later. Un less this is done, no comprehensive | records is secured
 With regard to prospecting for ear bonate and silicate ores, extra precau tions should be taken. These ores are often so friable that, in drilling, the cuttings are reduced to powder which cannot be identified by the eye. In such instances samples should be assayed Another point to be carefully guarded against is "self salting" This is most completely done by easing the drill hole Iall the way down, but where such easing is not complete the driller should care fully scrutinize all cuttings, and if q run of ore is found at level below one already discovered the gangue as sociations and character of the ore will often show whether the ore is new run or is a salting from the upper one
 "The cost of drill prospecting varie. with the method. If the land or lease holders operate their own drill rigs tho cost is considerably reduced if they meet the same conditions in the samC way as they are met under the con tract system. The objections to pri vate drilling come in the necessity of careful work with responsible men ir charge. To obtain this entails the em ployment of expert help and high wages. Such labor is hard to obtain and with rare exceptions it has been found that men who operate their own drill rigs under contract give the best results for the money expended. Drill ing contracts are let at stipulated price per foot, with no attention paid to the time element. The price usual ly paid is 90 cents per foot for all depths under 300 feet Over that depth the price is proportionately increased At the persent prevailing prices there is a good profit in drilling for the care. full and intelligent operator. The origin. al outlay is from $l,200 to $2,O00, for complete outfit. The expenses in. cluding ordinary breakage and repairs are from $S to sll per day, working ten hours and drilling from fourteen to twenty one feet. This gives a daily profit of $4 to 50. There are wide variations in the daily income on ac- count of the differences in ground, the easy propositions being almost all profit. When difficult proposition is found it entails loss of time and the abandonment, quite often, of hole, thus losing the work already done. In other instances an entire string of tools is lost which amounts to from $l25 to $1j0 in addition to the hole. Loss of tools, however, is not common where the driller exercises proper care and in telligence. The business of prospect drilling has grown to large proportions and an increasing number of contract drillers are constantly at work through out the district developing and extend ing the limits of the productive terri tory"