A revision of reserves in part of the Greymouth Coalfield, on the West Coast of the South Island of New Zealand, is presented, based on recent drilling and prospecting. Reserves have been calculated for three different groups of coal, and are summarised as follows: coal with swelling numbers of 9 and 9+ (suitable for gas making), 494,000 tons measured, 4,146,000 tons indicated, 4,960,000 tons inferred; coal with swelling numbers 9+ + and 9+ + + (suitable for metallurgical coke), 424,000 tons measured, 70,000 tons indicated, 16,700,000 tons inferred; coal with inconsistent swelling numbers from 1 to 9+, 382,000 tons indicated. Reserves in areas of coal belonging to more than one of these groups amount to 130,000 tons measured, 490,000 tons indicated, and 1,653,000 tons inferred.