Patent ID: 9151047
Filing Date: 2015-10-06
Classification: E02D,E04B,E21C

Abstract:
1. A method of forming a continuous concrete floor in an undercut excavation, the method comprising the steps of: a. excavating a first drift having a floor and side walls along its length; b. installing a pattern of reinforcing steel in the form of mesh, rebar or screen to provide adequate strength to a concrete floor to be poured over the reinforcing steel; c. installing forms around a perimeter of the floor of the first drift, wherein said forms installed against the walls of said first drift are a length equal to a length of any overlapping reinforcing steel to be installed in an adjoining drift when excavated; d. filling said forms with sand so the reinforcing steel is covered; e. then pouring or pumping concrete over the reinforcing steel and sand to form a concrete floor in the drift with a thickness sufficient to support cemented rock fill or the equivalent above the concrete floor when the drift is tightly backfilled; f. removing the forms; g. excavating a second drift having a floor and side walls along its length where the second drift is separated from the first drift by a third drift of unexcavated ore; h. forming a concrete floor on the floor of the second drift following the method of steps a-f; i. after the first drift and second drift have been backfilled with cemented rock fill, excavating a third drift between said first and second drifts, the third drift having a floor and side walls along its length; j. removing the sand covering the ends of the reinforcing steel from under the concrete floor of the first and second drifts along the portion of the periphery of the first and second drifts adjoining the periphery of the third drift; k. then providing reinforcing steel in the third drift extending to overlap the ends of the reinforcing steel in the first and second drifts; and l. pour or pump concrete over the reinforcing steel in the third drift to form a concrete floor in the third drift with a thickness sufficient to support cemented rock fill or the equivalent above the concrete floor when the third drift is tightly backfilled and the previous sand filled areas along the periphery of the first and second drifts and the overlapping reinforcing steel are covered with concrete to form a continuous concrete floor in the first, second and third drifts.