A Text-book of Coal-mining: For the Use of Colliery Managers and Others

advantage allow amount angle arrangement attached boring bottom cage carried cent centre closed coal Colliery connected considerable consists construction contain cost cylinder depth diameter direction distance drill driven drum employed engine equal explosive face feet fixed give given guides hole inches inclined increased Inst iron latter length less lever lifted load lower machine material means method mines motor moved necessary obtained operation ordinary passes pieces pipes piston placed plate position possible practice pressure prevent produced props pulley pump quantity rails reached reduced removed roads rock rods roof rope round seams shaft shown side sinking space speed steam steel stop stroke surface taken takes timber tool tube tubs turned valve vertical weight wheel winding wire yards