Application of 't' estimator for ore grade evaluation - a case study from Domiasiat uranium deposit, West Khasi Hills District, Meghalaya, India

The Sichel t estimator is generally used for estimating the average grade of an ore-body where the distribution of the element sought is lognormal. The computational aspects of t estimator have been simplified by numerically approximating the Sichel's function Φ (V) by a low-order polynomial. Further, a direct computation of t estimator is made possible by approximating γ(V) using Φ(V). According to Sichel the number of samples must be 100 in order to use t' estimator instead of t estimator. In this paper it is shown that not only the number of samples but also the sample volume plays an important role in using t' instead of t estimator. This is demonstrated by using shot hole logging data for uranium from the Domiasiat deposit. (author). 11 refs., 9 tabs., 4 figs