LME copper pulls back a bit more after mild overnight retreat to below $8,000/ton on forward selling, but potential supply problems at Grasberg mine still simmering, says trader; conflicting reports yesterday have left market confused on impact of strike on copper-gold mine operations, players awaiting clarity. Worker spokesman says protest to continue until tomorrow as negotiations on wages, benefits continue. LME 3-month copper last at $7,951/ton, down $34 vs PM kerb.