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Drilling Equipment, Operations and Limitations

A. Percy Wicklund, Mining Exploration Technology for Lawyers and Landmen (1980)

On exploration projects where drilling is required, that drilling cost may represent from 20 to 60 percent of the entire project's budget; however, by the time a mineralized zone is transformed into an economic ore deposit (that is a producing mine), the drill costs will vary from 1-1/2 percent to 6 percent of the total costs of that project.

Drilling is a requirement when property payments are due in short order or decisions required in operating. Mining companies categorize drilling as follows:

1.Exploration — or wildcat drilling

2.Mine evaluation — close spacing to check continuity and large diameter cores for metallurgical studies.

3.Mine operating which includes:

a.Mineable possible reserves — drilling on a wide grid pattern.

b.Mineable proven reserves — drilling on close centers for mine planning.

c.Mine grade control — to check grades of minerals being fed into a mill.

Up until a few years ago, diamond core drilling was the only accepted method of drilling. Today diamond core drilling amounts to between 30 to 35 percent of our exploration drilling with the remainder being drilled by various types of rotary or rotary percussive machines.

The success of a project depends largely upon the amount of investigation and research spent on the area to be drilled. Those of us who have the