Bogala vein graphite purity: mining 99% carbon crystallinity at 400-meter depths?

Sri Lanka is globally renowned for natural "vein" or "lump" graphite, mined primarily at Bogala and Kahatagaha-Kolongaha. Unlike flake or amorphous deposits elsewhere, local graphite formed through high-temperature hydrothermal fluids (exceeding 700°C) injected during granulite-facies metamorphic decompression along shear fractures in the Highland Complex. This yields solid crystalline vein walls requiring zero froth-flotation beneficiation to hit 97-99% fixed carbon purity. Ingress water in deep haulage winzes (reaching 400 meters sub-surface) is controlled by multistage centrifugal dewatering pumps discharging directly into surface settling ponds.