THE POTASH DEPOSITS IN VIENTIANE PLAIN, LAOS

Based on investigation and research on the regional geology, gravity, drilling,lithofacies and paleogeography, as well as the mining technology, the characteristics of the potash deposits in Lao Vientiane plain are known as follows: 1) The salt-bearing Paleogene Tagong formation (E₁tg) includes three apparent sedimentary cycles, which are composed of salt rock and terrigenous microclastic rock. The strata form a north-rising anticlinorium. 2) The main orebody occurs in the lower sub-member of Tagong formation (E₁tg^1-1) as bed, with thickness of 4.28 to 237.88 m (averagely 50.24 m), buried in 78.80 to 528.30 m (averagely 272.57 m) deep. The grade of KCl in single drill hole ranges from 9.70% to 30.76% (averagely 15.63%). The direct wallrock is salt rock. 3) The ore is mainly carnallite, with minor sylvite. 4) The deposits belong to ocean-sourced terrestrial potash deposit in clastic rock series.