Patent ID: 8789780

Claim:
A process for separating heavy metals from ore using an outer hollow cylindrical drum inclined relative to horizontal to define upper and lower ends and having at least one spiral vane extending inwardly from said outer drum's inner wall and radially extending lip at said lower end, an inner cylindrical barrel located within said outer drum and inclined relative to said outer drum, and at least one sluice box having upper and lower ends operatively coupled to said outer drum, 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 at least one sluice box, wherein the spiral vane is divided into a first section, second section, and third section, wherein the third section comprises a single height and the first section comprises generally a double height, and wherein a pitch of the third section is less than a pitch of the first and second sections rotating said inner barrel at a second speed greater than said first speed, directing discharge from said upper end of said outer drum as an input into said sluice box, and directing a spray of water into a trommel section of said inner barrel.