Question

The average grade of the mineral of a vein type of orebody with grade and thickness varying from place to place within the same orebody is arrived by

• A. Average of all grades
• B. Weighted average of all grades
• C. Median of all grades
• D. Mode of all grades

Hint:

For variable-width ore bodies, \[ \boxed{ \text{Average Grade} = \frac{\sum(\text{Grade}\times\text{Weight})} {\sum \text{Weight}} } \] where the weight is usually thickness or tonnage.

Answer 1

The Correct Option is B

Step 1: Recall the estimation of average grade. In a vein-type orebody, both the grade and the thickness vary from one location to another.

Step 2: Determine the appropriate averaging method. Since thicker sections contribute more ore than thinner sections, the average grade is calculated using a weighted average, where the weights are generally based on vein thickness or tonnage. Hence, \[ \boxed{\text{Weighted average of all grades}} \] is the correct answer. Therefore, \[ \boxed{(B)} \] is the correct answer.