Gold placer mining: placer evaluation and dredge selection.
Romanowitz CM; Bennett HJ; Dare WL
Denver, CO: U.S. Department of the Interior, Bureau of Mines, IC 8462, 1970 Jan; :1-56
This report deals with the factors which should be considered in evaluating a placer deposit and selecting a dredging system for mineral recovery. Overall dredging feasibility and the design of dredging systems are reviewed. Excavation methods, each with its advantages and disadvantages, are compared. Direct operating costs, both original and updated, of gold dredges with bucket capacities of 6 to 18 cubic feet are included. Costs vary with digging depth, changes in environmental conditions, and physical characteristics of the placer, all of which affect excavation rate and recovery. The costs, updated with appropriate indexes, should be used only as guidelines to evaluate potential dredging projects with similar characteristics. The relation of direct dredging costs to annual production is graphically illustrated by a family of curved envelopes that span dredge sizes from 2 1/2 to 18 cubic feet. A curve fitted to the data expresses the relation of direct costs to annual production.
IH; Information Circular
NTIS Accession No.
Denver, CO: U.S. Department of the Interior, Bureau of Mines, IC 8462