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2. Place pH 4.0 and pH 7.0 standard buffers in two plastic cups (one buffer in each cup). NOTE: NEVER return used buffers to stock bottles. 3. Place electrode in the pH 7.0 buffer. 4. Adjust pH meter to read pH 7.0. 1 5. Remove electrode from buffer solution and wash with a jet of distilled crater from a wash bottle. 6. Place electrode in the pH 4.0 buffer and check the pH reading. NOTE: If pH meter varies more than + 0.1 pH units from 4.0, something is wrong with the pH meter, electrode, or buffers. _ 7. Weigh 10 g of less than 60 mesh material into a paper cup. 8. Add 5 ml of distilled water to sample. NOTE: Do not stirt Allow water to wet sample by capillary action without stirring. With most overburden and minesoils materials, the 2:1 (soil:water) ratio provides a satisfactory paste for pH measurements; however, for the very coarse textured and the very fine textured material, more material or water can be lidded to bring the soil near saturation. At near saturation conditions, water should not be puddled nor dry soil appear at the surface. - 9. Stir sample with a spatula until a thin paste is formed adding more water or, soil as required to keep soil at saturation point. NOTE: At saturation, the soil paste glistens as it reflects light and the mixture slides off the spatula easily. Wash the spatula with a jet of distilled water before stirring another sample. 10. Place electrode in paste and move carefully about to insure removal of water film around the electrode. CAUTION: Do not trap particles between electrode_and ins ide_surface-of-the-sample.container. Electrodesare -- easily scratched. Contact between paste and electrode should be gentle to avoid_bath_impact-and-scratching=dams ge,=especially-in-sandy-sample s.-_— —__ 11.__When -reading-remains -constant,-record-pH--and-remove-electrode from-