ASTM D440-07

The values determined in this test method, when evaluated in terms of pertinent experience with other coals, may be used as indications of the extent to which coal will break in conventional transit and handling beyond the point of sampling.

1.1 This test method of drop shatter test covers the determination of the relative size stability and its complement, the friability, of sized coal. It affords a means of indicating the ability of coal to withstand breakage when subjected to handling at the mine and during transit to the consumer. The test method is serviceable for ascertaining the similarity of coals in respect to size stability and friability rather than for determining values within narrow limits in order to emphasize their dissimilarity. This test method is considered applicable for testing a selected single size of different coals, for testing different single sizes of the same coal, and for mixed sizes of the same or different coals. Note 1By single sizes is meant those with fixed upper and lower sieve opening limits, selected from those designated in ; and by mixed sizes is meant either "slack" or a mixture of two or more single sizes.

1.2 This test method appears best suited for measuring the relative resistance to breakage of the larger sizes of coal when handled in thin layers such as from loader to mine car, from loading boom to railroad car, from shovel to chute, etc. While it may not be so well adapted for measuring the liability to breakage of coal when handled in mass, as in unloading open-bottom cars, emptying bins, etc., it is believed that the test method will serve also to indicate the relative size stability of composite sizes of coal where, in commercial handling, the smaller sized pieces have a cushioning effect which tends to lessen the breakage of the larger pieces of coal.

1.3 The values stated in inch-pound units shall be regarded as the standard. Mass may be expressed in metric values.

This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.