&lt;Precambrian Shield ResourcesLtd>, earlier reporting a large loss against year-ago profit,
said the 1986 loss was mainly due to a 51,187,000 dlr writedown
on its U.S. operations, uneconomic coal and other mineral
properties.
    Precambrian, which is 89 pct owned by &lt;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 1986 loss of 53.4 mln dlrs,
compared to profit of 4.5 mln dlrs in the prior year.
 Reuter
