Uranium Exploration of Samar Island

摘要

Uranium exploration is being undertaken to meet the requirements of the Philippine Nuclear Power Plant-1 (PNPP-1) programmed to operate in 1982, for about 140 metric tons annually or 2664 MT of U sub 3 O sub 8 up to the year 2000. Samar was chosen as the survey pilot project and the method used was a geochemical reconnaissance or low density observation survey to delineate broad areas where follow-up uranium surveys may be undertaken. Stream sediments or surface waters were collected at each sampling point at a density of one sample per 20-25 sq. km. The conductance and pH of the water were measured with a conductivity meter and pH respectively. Radioactivity was determined using a portable scintillometer. The stream sediment and heavy mineral samples were analyzed for uranium (U), copper (CCu), lead (Pb), zinc (Zn), manganese (Mn), silver (Ag), cobalt (Co), nickel (Ni). Water samples were analyzed for uranium only. The solid samples were digested in an acid mixture of 85% concentrated nitric acid and 15% concentrated hydrochloric acid, and the leachable uranium was determined using a fluorimeter. The detection limits for uranium were 0.3 ppb and 0.3 ppm for water and solid samples, respectively. Analysis for Cu, Pb, Zn, Mn, Ag, Co, and Ni were done by Atomic Absorption Spectrophotometry using the same leaching solution prepared for uranium analysis. Over 9000 determinations were done on nearly 1600 samples. The survey delineated at least two areas where follow-up surveys for uranium are warranted. These areas are the San Isidro - Catarman in Northwestern Samar, and the vicinity of Bagacay mines in Central Samar. (Atomindex citation 10:454989)