This paper reviews evidence for the assignments of components of the S 2p XPS spectra from sulphide mineral surfaces under different conditions of preparation, oxidation and reaction. Evidence from other techniques confirming assignment of high‐binding‐energy S 2p components to metal‐deficient sulphide surfaces, polysulphides, elemental sulphur and electronic defect structures is considered for specific cases. Reliable assignment of S 2p3/2 components at 163.6–164.0 eV to elemental sulphur Sn0 can be confirmed by evaporative loss at 295 K and/or observation of S–S bonding by x‐ray absorption fine structure (XAFS), x‐ray diffraction or vibrational spectroscopy. Assignment to polysulphides Sn2− at 162.0–163.6 eV requires confirmation of S–S bonding by XAFS or vibrational spectroscopy. Metal‐deficient lattices can be represented as electronic defects (e.g. vacancies) or restructured surface phases confirmed by diffraction or XAFS evidence. High‐binding‐energy S 2p3/2 components can also result from Cu(I) substitution into ZnS with associated oxidation of sulphur as electronic defect sites without S–S bonding, metal deficiency or restructuring. This assignment is confirmed by XAFS evidence. Copyright © 1999 John Wiley & Sons, Ltd.

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Chemical calculations based on the molar quantity of neutralizing cations (Na, K, Mg, Ca, Mn) released to solution associated with the acidic dissolution of minerals provide a method to chemically quantify the acid-neutralization capacity (ANC) of carbonates, silicates, simple assemblages of mixed minerals, and waste-rock samples obtained from international mining operations. The acidity neutralized by each cation is equivalent to its valence within the mineral structure. Fe and Al are hydrolyzed during the ANC back-titration and thus are effectively non-acid-neutralizing cations. Sulfur derived from pyrite oxidation is equivalent to the release of two moles of H + , although non-acid-forming S (e.g., gypsum) should be addressed. Calculations based on these principles for the samples tested correlate well with the ANC determined by titration-type tests.

A simple technique is presented for the longitudinal sectioning of hair samples without the need for any embedding medium. The technique applies to single hair samples that are placed in a groove of a particular depth and can either be scraped or cut to the desired level. Planar sections are obtained that reveal the internal structure of the sample and are ideal for the application of surface analytical techniques for the study of internal transverse and longitudinal distributions of xenobiotics.