The effects of using surfactant solutions while diamond drilling in amygdaloidal basalt of the Upper Michigan Copper Mining District were investigated. Nonionic, anionic, and cationic surfactant solutions, all biodegradable, were tested with size AX surface-set bits mounted on a drill instrumented for continuous recording of thrust, rotational speed, and torque levels. Water flow and penetration rates were also recorded.

A drilling study was carried out, testing two rotational speed levels, two diamond bit grade levels, and four flushing agents (including water as control). The lower speed and higher thrust yielded faster penetration rates over those of the higher speed/lower thrust combination. Comparison of all low-speed/high-thrust groups of tests shows that the nonionic surfactant produced a 35-percent overall average increase over water, the anionic a 29-percent increase, and the cationic a 28-percent increase. These increases in penetration rates resulted in a 22- to 26-percent penetration rates resulted in a 22- to 26-percent reduction in cost over flushing with water alone.

Particle size analyses were run on drill cuttings produced by the three surfactant solutions and by water. All surfactant solutions showed a 20- to 50-percent increase in solids content over that of water alone. Since flushing rates were constant, these increases in solids content agree well with the above penetration rate changes.

The diamonds were recovered from each bit by matrix dissolution, and bit wear was measured in terms of total loss of weight. Flushing with surfactant solutions showed a savings in bit wear in most cases.

The drill team noted also that surfactant flushing improved recovery of drill core by allowing easier removal of the core from the barrel.

Statement of Problems in the Native Copper Mining Industry

Exploration diamond drilling in the native copper mining industry of Upper Michigan started about 1882. The purpose has been to provide geological data, to map out ore provide geological data, to map out ore reserves, and to better plan mining operations. Since most of this diamond drilling has been from underground locations, only lightweight, low-powered drills can be used.

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