The weight of an object in the coal mine, sea level and at the top of the mountain are respectively W1, W2 and W3, then

g at certain depth is g1 = g(1 -d/R)Weight in mine is w1 = mg1 = mg(1-d/R)weight at sea level w2 = mg    ( acceleration due to gravity is the  gravity at sea level) g at certain height is g11 = GM/(R+h)2                                  g11 = gR2/(R+h)2                                    g11 = g(1-2h/R)weight at mountain is w3 = mg11 = mg(1-2h/R)w1 < w2 > w3