US 4,451,357 A · Apparatus for dry placer mining and method of operating same

Abstract

An apparatus for dry placer mining to concentrate recoverable metallic constituents, such as gold or silver, from a dry gravel mix containing same is comprised of a frame for supporting and guiding an endless belt along a path including an upwardly inclined segment for receiving gravel particulate; an endless belt including a woven mesh belt member, a plurality of riffle members disposed in spaced parallel relationship within the intertices of the mesh member, and a composite fabric member disposed in face-to-face contact with the bottom surface of the mesh member; and a fluidizing member for passing a fluidizing gas upwardly through the endless belt along the inclined segment for fluidizing the gravel particulate and for establishing an electrostatic charge proximate the riffle members. The composite fabric member is specially constructed to permit a proper airflow for fluidizing the particulate and for assisting in the establishment of an electrostatic potential proximate the riffle members. This special construction includes a layer of an air-pervious polymeric foam disposed intermediate a pair of cloth fabric layers having progressively tighter weave patterns.

Claims18

Dependent claims

Apparatus for dry placer mining to concentrate metallic constituents from a gravel mix comprising same, said apparatus comprising:

a. a frame for supporting and guiding an endless separation belt along a closed path including an upwardly inclined segment for receiving a gravel mix containing a low concentration of metallic constituents;
b. endless separation belt means, including:
(i) a woven mesh belt member having raised loop elements and transversely extending interstices;
(ii) a plurality of riffle members disposed in spaced, generally parallel relationship through selected ones of said interstices;
and,
(iii) a composite fabric member secured to the underside of said mesh belt, comprising a layer of air-pervious polymeric foam disposed intermediate upper and lower layers of cloth fabric;
and,
c. fluidizing means for passing a fluidizing gas upwardly through said separation belt substantially uniformly along and about said upwardly inclined segment to fluidize said gravel mix and concomitantly establish an electrostatic charge proximate said separation belt;
wherein the combined fluidization of gravel and electrostatic charge effectuate a substantial separation of said metallic constituents from said mix and retention of the former proximate said riffles thereby concentrating the metallic constituents for recovery.

6 more elements

Apparatus for dry placer mining comprising:

a. a pivotal frame for supporting and guiding an endless separation belt along a closed path including a gravel receiving and fluidization segment;
b. an endless separation belt consisting essentially of first and second endless woven mesh segments disposed side by side, each of which webs includes raised loops defining closed transverse channels of interstices, a series of riffles disposed in spaced, parallel relationship through certain of said channels to yield transverse collection zones separated and bounded by adjacent riffles, and a composite fabric backing of a layer of air-pervious polymeric foam disposed intermediate upper and lower cloth fabric layers comprised of synthetic fibers;
c. integral drive chains formed in said belt at either edge and intermediate the location of said first and second woven mesh web segments, each of said chains including a series of links comprised of first and second connecting bars joining two successive riffles and a roller member disposed between said connecting bars;
d. guard means confining the path of gravel to one along said receiving and fluidizing segment, said guard means comprising an upstanding, peripheral row of a plurality of guard plates disposed proximate each edge of said mesh web segments wherein each of said guard plates spans two successive riffles;
and,
e. fluidizing means for fluidizing gravel particulate conveyed upon said separation belt through said fluidization segment.

3 more elements

Dependencies are inferred from the claim text.

Apparatus for dry placer mining and method of operating same

Life of this patent

Apparatus for dry placer mining and method of operating same

Life of this patent

Abstract

Claims18