ASTM D6234-98(2007)

This test method is intended as a means for obtaining an extract of mining waste. The extract may be used to estimate the release of certain inorganic constituents of the waste under the laboratory conditions described in this test method. The user is advised to minimize the holding time between sampling and testing if the waste is suspected to contain reactive sulfide minerals.

Note 2—This method is not intended to be used as a kinetic test to simulate weathering of mining wastes. For kinetic testing of mining wastes, refer to Test Method D 5744 to determine release rates for constituents of interest.

The pH of the extraction fluid used in this test method is to reflect the pH of acidic precipitation in the geographic region in which the waste being tested is to be disposed (see 1.2).

An intent of this test method is for the final pH of the extract to reflect the interaction of the extractant with the buffering capacity of the waste.

This test method is not intended to provide an extract that is representative of the actual leachate produced from a waste in the field or to produce extracts to be used as the sole basis of engineering design. If the conditions of this test method are not suitable for the test material USEPA Method 1312 may be used.

This test method has not been demonstrated to simulate actual disposal site leaching conditions.

This test method produces extracts that are amenable to the determination of both major and minor (trace) inorganic constituents. When minor constituents are being determined, it is especially important that precautions be taken in sample storage and handling to avoid possible contamination of the samples.

This test method has been tested to determine its applicability to certain inorganic components in the waste. This test method has not been tested for applicability to organic substances, volatile matter (see Note 4), or biologically active samples. This test method has undergone limited testing to determine its reproducibility.

1.1 This test method covers a procedure for the shake leaching of mining waste containing at least 80 % dry solids ( 20 % moisture) in order to generate a solution to be used to determine the inorganic constituents leached under the specified testing conditions, that conform to the synthetic precipitation leaching procedure (SPLP).

1.2 This test method calls for the shaking of a known weight of mining waste with acidic extraction fluid of a specified composition as well as the separation of the liquid phase for analysis. The pH of the extraction fluid is to reflect the pH of acidic precipitation in the geographic region in which the waste being tested is to be disposed.

Possible sources of information concerning the pH of the precipitation in the geographic region of interest include state and federal environmental agencies, state universities, libraries, etc. pH values given in USEPA Method 1312, that are 4.2 east of the Mississippi River and 5.0 west of the Mississippi River and are based on acid precipitation maps, are examples of values that can be used. If the pH of the laboratory water is less than the desired pH for the site, do not use this test method, use Test Method D 3987.

1.3 This test method is intended to describe the procedure for performing single batch extractions only. It does not describe all types of sampling and analytical requirements that may be associated with its application.

1.4 The values stated in SI units are to be regarded as the standard.

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.