Abstract
The Katta Mine is mining the bedded type body of gypsum in a Miocene green coloured tuff breccia, that is thought to belong to a type of Black Ore in Japan.
The gypsum body consists of massive alabaster, impregnated gypsum and aggregate of spheluritic gypsum of 0.5-2.0cm in diameter. The aggregate occupies the almost all parts of the ore body. A number of gypsum sphelurite have a radiated structure.
The occurrence of magnesium chlorite in the high grade gypsum ore is ascertained from the results of X-ray powder diffractions and differential thermal analyses. This mineral is thought to be useful to the ore prospecting.
The clay mineral that is universally detected both in an ore body and in its environs is sericite. The writers would like to emphasize that the deposition of gypsum is due to the diffusion of hydrothermal ore solution through a sericite clay which is formed by the pre-ore action and is maintained in a colloidal state.
