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Sample preparation variability in diamond-drill core from the Homestake Mine, Lead, South Dakota.

Koch GS Jr.; Link RF
NTIS: PB 213 062 :1-15
In preparing diamond-drill core samples for assay at the Homestake mine, Lead, S. Dak., 5-Foot intervals of core are processed through three stages, crushing, grinding, and pulverizing, and portions of the core material are discarded after splitting at each stage of preparation. Then two 1-assaying fractions are taken from the pulverized material and assayed. This report investigates alternative methods of sample preparation. The consequences of crushing, grinding, and pulverizing all rather than part of the core are appraised through the statistical analysis of assay results from 118 5-foot intervals of core. Evidently, a substantial improvement in precision at small additional expense is obtained by grinding most or all of the core before splitting. Pulverizing all of the core would be desirable only if doing so would cost less than assaying five random splits from each interval. Graphs and tables detail appropriate procedures to obtain specified precisions. The experimental design and methods can be applied to similar problems in preparing core and other geological samples.
Publication Date
Document Type
IH; Report of Investigation;
Fiscal Year
NTIS Accession No.
NTIS Price
Identifying No.
RI 7677
NIOSH Division
Source Name
NTIS: PB 213 062
Page last reviewed: December 10, 2021
Content source: National Institute for Occupational Safety and Health Education and Information Division