Interaction of specific 1-D deployment schemes and meso-scale sampling of elongated lots of free-flowing aggregate materials

Lars Petersen Julius (Foredragsholder)

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The Theory of Sampling (TOS) embodies a complete theoretical analysis of all sampling errors (and resulting sampling bias' and variances) associated with all types of sampling process. In particular, sampling of 0- and 1-dimensional stationary bodies is well covered, for which the major sampling errors are the Fundamental Sampling Error (FSE), the Grouping and Segregation Error (GSE) and sampling errors introduced by incorrectness. Sampling incorrectness is comprised of three parts, of which two relate to the lot/material properties and the third to the sampling process itself. Qualitatively it is easy to analyze a particular sampling scenario and select the most appropriate, correct sampling procedures and equipment. It is a well-known fact from the world of practical sampling however, that the combination of material characteristics and sampling process correctness often vary within specific lot geometries, dependent upon the loading/deployment of the lot in question. Here we present selected results from an extensive scaled-down sampling experimental campaign in which elongated (1-dimensional) bodies of aggregate material are laid up by alternative schemes often used in the industrial practice (shoveling by front-loader, longitudinal and cross-wise windrow deployment, as well as chevron deployment) and subsequently sampled by a suite of the world's most often used sampling procedures: grab sampling, composite surface sampling, core-drilling (single, composite) and trenching (transverse and longitudinal). The results overall confirm the general deductions from the theory of sampling, albeit with interesting peculiarities, all related to specific deviations of local heterogeneities and to inherent deficiencies in some of the investigated sampling procedures. This study forms an empirical parallel to the extensive, although slightly less realistic simulation studies of Robinson (2004) on similar industrial stockpile stacking and reclaiming.


Emneord: Sampling, Theory of Sampling, Pile, Chevron, Windrow, Grab sampling, Drill-core sampling, Composite sampling
Periode25 okt. 2007
BegivenhedstitelWorld Conference on Sampling and Blending (WCSB3)
PlaceringPorto Alegre, Brasilien