Abstract:
The Bogala Graphite Mines in Sri Lanka is experiencing a considerable water flow problem for more than two decades which has resulted in increasing total production cost due to high dewatering cost. This case study was basically carried out to optimize the mine dewatering cost by preventing water inflow where possible. This paper describes only the phase 1 of the study, which is "The identification of water recharge sources in to the mine". Major water seepage takes place above 72 fathom (fm) levels and a significant inflow is at 52 fathoms level which discharges water at a rate of 8.5 liters/so Initially, major joints/fractures above 72 fathom were measured and the fracture network in the problematic area of the mine was developed. Interpretation of the fracture
model provided valuable data on water recharge locations. Simultaneously
environmental isotopes (2H and 18() analysis on surface, subsurface water
bodies and underground seepage locations were carried out to identify the exact
water recharge locations. The 2H and 180 contents were plotted in graphs in
various suspected combinations with local meteoric water lineto identify
interconnections. Even though, some solutions were presented to reduce the
mine dewatering cost, further analysis is needed with continuous sampling of
data to confirm the tentative conclusions.
