ONE of the most important operations of economical mining the quick and cheap replacement of extracted ore is provided for in the North mine by a system of distribution of the filling in the lower levels by means of conveyor belts. The mine was already partly developed on the 800-ft. level when the present management faced the problem of providing an efficient distributing system. Above that level the reserves of ore did not warrant the heavy cost of installing a system that would fit in with the then existing lay-out of the mine. The distribution of filling in this portion of the mine is still effected by means of trucking. The filling consists of residues from the concentrating mill. The main channels for the gravity run of filling consist of three mullock passes. These passes are carried down outside the limits of the ore-bodies, and the filling is conveyed from these passes on the different levels to the various winzes in the ore bodies themselves. A complete distribution of the filling is made to every winze on each successive level, the practice of passing filling from level to level through working stopes being in no place adopted. The advantages of this are many, the chief being that in no place are stoping operations hindered on account of filling operations, and vice versa.