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Testwork normally means tests performed in a laboratory on samples of ore from a particular mineral deposit. There are several different tests that are used in the industry, and only the ones relevant to Power Models are used in the SAGMILLING.COM databases.

Grouping tests by size class

Tests can normally be grouped based on the size class they are investigating, and there will normally be reasonably strong correlation between tests in the same size classes.

  • Coarse tests are the Bond impact crushing work index, the point load index and the unconfined compressive strength. The Minnovex CI (part of the SGS SPI™ protocol) often reflects the breakage of coarse sizes, even thought the specimens used aren't particularly coarse.
  • Medium tests are the Bond rod mill work index, SGI, and the drop weight tests (DWT). Other tests that aren't part of the database usually fit into this range; examples are SAGDesign and MacPherson tests.
  • Fine tests means exclusively the Bond ball mill work index test. The Morrell Mib value can be determined from the Bond results and it isn't considered a distinct test from the standpoint of the database.

Grouping tests by type of apparatus

Another way to group tests is by the type of apparatus used in the test:

  • Drop Weight Tests are tests performed by vertically dropping a weight on a sample and measuring the resulting particle sizes. The JK Drop Weight Test and the SMC test are both classed as Drop Weight Tests.
  • Tumbling Tests are tests performed by tumbling sample in a rotating mill that contains some sort of media. The Bond rod mill and ball mill work index tests, SGI and Bond abrasion index tests are all Tumbling Tests.
  • Pendulum Tests are tests where a pendulum (usually a pair of pendulums) strikes the sample horizontally. The Bond impact crushing work index is an example of a Pendulum Test.