Achieving Reliable Gravity Discharge from Ore Stockpiles

  • Industries: Energy & Power, Mining & Minerals
  • Main Bulk Solids: Ore

The Need

As a result of segregation, even the presence of as little as 10% fines (-5 mesh) in an ore can lead to serious flow problems in stockpile reclaim via tunnel systems.  If the fines are cohesive and gain strength as a function of consolidation pressure, then ratholes may form above discharge hoppers, severely reducing the live capacity of the stockpile, or arches may form across hopper outlets, leading to flow stoppages.

  • Needs Addressed: Address Process Non-Uniformity, Cure Segregation & Improve Blending, Solve or Prevent Poor Flow
  • Bulk Material Handled: Ore
  • Equipment: Storage, feeder

The Solution

Jenike & Johanson performed a series of tests on scale models of a variety of large storage piles.  The purpose of these tests was to compare and measure the live capacity for a pile comprised of coarse, free-flowing material with the capacity of a pile comprised of the same material mixed with different percentages of fines.

The Result

We found that when no more than 5% fines was added to the coarse product, complete draw down occurred and the live capacity could be accurately calculated using a 3D CAD program based on knowing only the measured “drawn down” angle of repose.  By knowing the properties of the bulk solid, a gravity stockpile reclaim system was correctly designed providing the most economical and effective method of reclaiming the stockpile.