Optimum Sampling Interval (1 reply)

Oberfuhrer
8 years ago
Oberfuhrer 8 years ago

What is the maximum and minimum sampling interval that is suitable for drill cores from a first phase drilling in a porphyry Cu-Au deposit?

Paul Morrow
8 years ago
Paul Morrow 8 years ago

There is no simple answer to sample length, you need to consider geology, mineralisation, structural controls, drilling methods, mining methods, sample preparation techniques and ultimately is the copper and gold going through the same processing plant.

Always sample to geological contacts, particularly if there is late (secondary) gold mineralisation. Generally porphyry copper deposits will be relatively homogenous and therefore larger samples are OK. As it is first phase of drilling I would tend toward shorter intervals, and then later in the programme once an appreciation of mineralisation is known, go with a larger multiple of smaller initial sample intervals.
Perhaps common is 3m as that is a drill run, but I have seen 2, 3, 4, 5 and 10m samples collected routinely.

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