Following is given the comparative cost of drilling with the spring pole and the diamond drill in the case under consideration, where they have been operated under similar conditions:
Cost of Spring-Pole Outfit and Drilling- Following is given the cost of 3-inch spring pole drilling outfit, including labor and material.
The cost of moving, sharpening tools, repairs, etc. for each hole will be about as follows:
The daily cost of labor, drilling a 3-inch hole, is as follows:
If 6 to 7 feet are drilled daily the cost per foot will be 82 to 96 cents for labor [per foot drilled]. The total cost of drilling will therefore be:
Cost of Diamond-Drill Boring-
At right is given the cost of drilling a 1 ¼ inch hole with diamond drill. The daily cost of labor drilling: If 18 to 20 feet are drilled daily, the cost per foot will be 60 to 70 cents for labor.
The cost of dismantling, moving, and erecting for each hole is as follows:
The total cost of drilling per foot will therefore be as follows:
Provided there was a sufficient amount of drilling to absorb the first cost of a diamond-drilling outfit, and other conditions were favorable, the cost of the diamond-drilling boring per foot will not greatly exceed that of the spring-pole drilling. if fuel and water are scarce, this item of cost as above shown, will be greatly increased.
In conclusion, the conditions first mentioned governing the use of the spring pole are:
1. Where only a small amount of drilling is to be done
2. If only moderate cost is to be incurred
3. If great speed is not required.
from "The School of Mines quarterly, Volume 16 By Columbia University. Henry Krumb School of Mines, Columbia University. School of Engineering and Applied Sciences"
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