4.1 These test methods are primarily intended to test materials for compliance with compositional specifications and for monitoring.

4.1.1 The determination of carbon and sulfur and acid neutralization potential in ores and related materials is necessary to classify ores for metallurgical processing and to classify waste materials from the mining and processing of ores such as leach residues, waste rock, and tailings according to their potential to generate acid in the environment. This information is useful during mine development to assist in mining and mineral processing operations and for proper disposal of waste materials.

4.1.1.1 The use of the acid neutralization potential titration low range method is most useful where acidity is present in the samples and when acid potential by titration is desired in the uncertain content range below 2 % CaCO₃.

4.1.2 These test methods are also used to isolate minerals based on carbon and sulfur contents of metal-bearing ores and related materials so that acid-base accounting can be performed (that is, carbonate mineral acid neutralization potential (ANP) minus sulfide-sulfur mineral acid generation potential (AGP) = net calcium carbonate (NCC)).

4.1.3 Additionally, the carbon hydrochloric acid insoluble test method has utility to identify the amount of organic carbon contained in gold ores so that potential for preg robbing can be identified and rectified through established pretreatment methods prior to cyanidation. Warning-Pyrolysis pretreatment at 550 °C has a potential to thermally decompose some carbonate minerals: (1) transition metal carbonates (for example, siderite, FeCO₃, and rhodochrosite, MnCO₃) decompose, yielding carbon dioxide, CO₂, in the range of 220 °C to 520 °C; (2) calcite decomposes slightly between 300 °C and 500 °C, although most decomposition occurs above 550 °C; (3) dolomite decomposes at 800 °C to 900 °C (Hammack, 1994, p. 440).³

4.2 These test methods also may be used for the classification of rock to be used in construction, where the potential to generate acid under environmental conditions exists.

4.3 It is assumed that the users of these test methods will be trained analysts capable of performing common laboratory procedures skillfully and safely. It is expected that work will be performed in a properly equipped laboratory and that proper waste disposal procedures will be followed. Appropriate quality control practices such as those described in Guide E882 must be followed.