Apparatus for extrating heavy metals from ore

Apparatus for recovering heavy substances from raw material comprising:

• (a) an outer hollow drum mounted at an inclination relative to horizontal so as to define upper and lower ends thereof and having a radially inwardly directed lip at its lower extremity and having an inner cylindrical wall with vane means mounted thereon that extends in a helical spiral on said inner cylindrical wall between said upper and lower ends of said drum;
• (b) an inner hollow barrel mounted within said drum inclined relative to horizontal and having an upper section with an annular cylindrical wall having a plurality of impact vanes extending inwardly therefrom and aligned longitudinally therealong, an intermediate section coaxial with said upper section and delineated therefrom at a radially inwardly extending upper annular lip and having an annular cylindrical wall with a multiplicity of openings therein whereby said intermediate section serves as a trommel, and a lower section coaxial with and delineated from said intermediate section by a radially inwardly extending intermediate annular lip and having a solid cylindrical annular wall with a radially inwardly extending lower annular lip at its lower extremity;
• (c) a sluice box positioned so as to receive discharge from the upper end of said outer drum;
• (d) means for directing a spray of water toward said intermediate section of said inner barrel;
• (e) means for supplying a flow of water to said sluice box;
• (f) means for rotating said outer drum at a first speed in a direction such that said spiral vane means urges material within said drum toward said upper end thereof;
• and
• (g) means for rotating said inner barrel at a speed greater than said speed of said outer drum.

A process for separating heavy materials from ore using an outer hollow cylindrical annular drum inclined relative to horizontal to define upper and lower ends and having at least one spiral vane extending inwardly from its inner wall and a radially inwardly extending lip at said lower end, a cylindrical annular barrel located within said drum and inclined relative to horizontal and having an upper fragmentation section, an intermediate trommel section, and a lower discharge section delineated from each other by inwardly directed annular lips and having a radially inwardly extending lip at its lower extremity, and a sluice box having upper and lower ends, comprising the steps of:

• rotating said outer drum at a first speed in a direction such that said spiral vane urges material therein toward said upper end of said outer drum and toward said upper end of said sluice box,
• rotating said inner barrel at a second speed greater than said first speed,
• directing discharge from said upper end of said drum as an input into said sluice box, and
• directing a spray of water into said trommel section of said inner barrel.