	precambrian shield takes mln dlr writedown precambrian shield resources ltd earlier reporting a large loss against year ago profit said the loss was mainly due to a dlr writedown on its u s operations uneconomic coal and other mineral properties precambrian which is pct owned by mark resources inc said it took the writedown in accordance with new canadian insititute of chartered accountants guidelines for full cost method accounting by oil and gas companies precambrian earlier reported a loss of mln dlrs compared to profit of mln dlrs in the prior year reuter 
