Which deeper test approximates ore grade by processing a representative volume of ore before full-scale mining?

• A. Open pit
• B. Character sample
• C. Drift
• D. Bulk sample

Answer: (D)

Testing ore grade before committing to full-scale mining relies on bulk sampling. By processing a large, representative volume of ore, this approach captures the natural variability of the deposit and provides a realistic measurement of grade, as well as how well the ore behaves in processing and what the recoveries might be. It gives practical insight into the economics of mining the deposit, since you’re evaluating a plant feed similar in scale to what would be produced, not just a tiny hand sample.

Open pit and drift refer to mining methods rather than a way to estimate ore grade from a large sample, so they don’t address the testing of grade through processing. A character sample uses small, focused samples to characterize ore, but it may not reflect the overall variability or how the whole ore body would perform in processing. Bulk sampling specifically aims to approximate the real grade by processing a representative volume, making it the most appropriate approach in this context.