|Missouri University of Science and Technology
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"In prospecting for copper by means of churn drills it is absolutely essential that accurate methods of sampling be employed if any dependence is to be put upon the results. Of equal importance is the recording and preservation of data regarding each hole after results are obtained. This applies to such information as location and elevation of holes, depth, water level, geology etc., as well as to the assays of the samples. Future underground development will be guided by information obtained from the drill holes and any incompleteness in the records will cause uncertainty in the development of the mine. This applies especially in a district like this where ore bodies are extremely irregular and difficult to block out" – Introductory Remarks, leaf 4.