A Framework for Representative Sampling for NIR Analysis – Theory of Sampling (TOS)

2021 ◽  
pp. 415-462
Author(s):  
Kim H. Esbensen ◽  
Rodolfo J. Romañach
Keyword(s):  
Representative Sampling ◽  
Analysis Theory ◽  
Theory Of Sampling

scholarly journals Integrating the Theory of Sampling into Underground Mine Grade Control Strategies: Case Studies from Gold Operations

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 238
Author(s):  
Dominy ◽  
Glass ◽  
O’Connor ◽  
Lam ◽  
Purevgerel
Keyword(s):  
Case Studies ◽  
Control Strategies ◽  
Control Process ◽  
Control Programme ◽  
Small Scale ◽  
Sampling Errors ◽  
Sample Collection ◽  
Representative Sampling ◽  
Grade Control ◽  
Theory Of Sampling

Grade control aims to deliver adequately defined tonnes of ore to the process plant. The foundation of any grade control programme is collecting high-quality samples within a geological context. The requirement for quality samples has long been recognised, in that these should be representative and fit-for-purpose. Correct application of the Theory of Sampling reduces sampling errors across the grade control process, in which errors can propagate from sample collection through sample preparation to assay results. This contribution presents three case studies which are based on coarse gold-dominated orebodies. These illustrate the challenges and potential solutions to achieve representative sampling and build on the content of a previous publication. Solutions ranging from bulk samples processed through a plant to whole-core sampling and assaying using bulk leaching, are discussed. These approaches account for the nature of the mineralisation, where extreme gold particle-clustering effects render the analysis of small-scale samples highly unrepresentative. Furthermore, the analysis of chip samples, which generally yield a positive bias due to over-sampling of quartz vein material, is discussed.

scholarly journals Sampling commitment—and what it takes…

2019 ◽  
pp. 24-28
Keyword(s):  
Case Histories ◽  
Representative Sampling ◽  
Know How ◽  
Technology Industry ◽  
Current State ◽  
Theory Of Sampling

This column concludes the first series of Sampling Columns. More will appear in a sequel series, mainly aimed at presenting practical examples, case histories, demonstrations—all of which will assume that the value of only practicing representative sampling has been fully acknowledged and the relevant know how has been comprehended. Here, we end the first educational exposé of the Theory of Sampling (TOS) by focusing on the current state of awareness and with an acknowledgement of the need to involve TOS in all relevant international scientific fora, in technology, industry and in the commercial marketplace.

scholarly journals Representative Sampling Implementation in Online VFA/TIC Monitoring for Anaerobic Digestion

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1179
Author(s):  
Camilo Wilches ◽  
Maik Vaske ◽  
Kilian Hartmann ◽  
Michael Nelles
Keyword(s):  
Human Error ◽  
Sampling Errors ◽  
Sampling System ◽  
Representative Sampling ◽  
Anaerobic Reactors ◽  
Biogas Plants ◽  
Theory Of Sampling ◽  
Online Monitoring System ◽  
Analysis Error ◽  
Representative Samples

This paper describes an automatic sampling system for anaerobic reactors that allows taking representative samples following the guidelines of Gy’s (1998) theory of sampling. Due to the high heterogeneity degree in a digester the sampling errors are larger than the analysis error, making representative sampling a prerequisite for successful process control. In our system, samples are automatically processed, generating a higher density of data and avoiding human error by sample manipulation. The combination of a representative sampling system with a commercial automate titration unit generates a robust online monitoring system for biogas plants. The system was successfully implemented in an operating biogas plant to control a feeding-on-demand biogas system.

Critical Practicalities in Sampling for Mycotoxins in Feed

2015 ◽  
Vol 98 (2) ◽  
pp. 301-308 ◽  
Author(s):  
Claas Wagner
Keyword(s):  
Economic Loss ◽  
Field Trials ◽  
Optimal Number ◽  
Representative Sampling ◽  
Extensive Field ◽  
Sampling Protocols ◽  
Theory Of Sampling ◽  
Trace Concentrations ◽  
Correct Design

Abstract The presence of mycotoxins, in particular aflatoxin B1, can cause significant health problems as wellas severe economic loss, and are therefore regulatedwith respect to maximum acceptable concentration forvarious feed- and foodstuffs. International regulatory authorities have recognized the importance of representative sampling, and sampling guidelines that only partly comply with the Theory of Sampling have been formulated. Practical guidance regarding sampling, including correct design and operation of sampling devices and explanations on how to develop sufficient sampling protocols are lacking in current guidelines. These are critical practicalities of main importance, especially when dealing with trace concentrations and/or concentrations that are irregularly distributed, as for mycotoxins. Heterogeneity characterization, which is necessary to be able develop validsampling protocols or validation assessments of existing sampling operations, is currently not mentionedin the existing guidelines. This paper explains all critical practicalities with respect to sampling of mycotoxins for 1-D and 3-D feed decision units. Correct design and use of sampling and mass reduction devices, as well as structural guidelines for correctly designing experimental heterogeneity characterizations are presented, allowing evaluation of sampling representativeness and determination of optimal number of increments per composite sample. Practical examples are given on how to extract information from variographic analysis and replication experiments, based on an extensive field trials performed to determine aflatoxin levels in various feed components.

scholarly journals Local versus field scale soil heterogeneity characterization – a challenge for representative sampling in pollution studies

SOIL ◽  
2015 ◽  
Vol 1 (2) ◽  
pp. 695-705 ◽  
Author(s):  
Z. Kardanpour ◽  
O. S. Jacobsen ◽  
K. H. Esbensen
Keyword(s):  
Large Scale ◽  
Environmental Chemistry ◽  
Soil Heterogeneity ◽  
Environmental Pollutant ◽  
Small Scale ◽  
Compositional Variation ◽  
Sampling Point ◽  
Representative Sampling ◽  
Research Areas ◽  
Theory Of Sampling

Abstract. This study is a contribution to development of a heterogeneity characterization facility for "next-generation" soil sampling aimed, for example, at more realistic and controllable pesticide variability in laboratory pots in experimental environmental contaminant assessment. The role of soil heterogeneity in quantification of a set of exemplar parameters is described, including a brief background on how heterogeneity affects sampling/monitoring procedures in environmental pollutant studies. The theory of sampling (TOS) and variographic analysis has been applied to develop a more general fit-for-purpose soil heterogeneity characterization approach. All parameters were assessed in large-scale transect (1–100 m) vs. small-scale (0.1–0.5 m) replication sampling point variability. Variographic profiles of experimental analytical results from a specific well-mixed soil type show that it is essential to sample at locations with less than a 2.5 m distance interval to benefit from spatial auto-correlation and thereby avoid unnecessary, inflated compositional variation in experimental pots; this range is an inherent characteristic of the soil heterogeneity and will differ among other soils types. This study has a significant carrying-over potential for related research areas, e.g. soil science, contamination studies, and environmental monitoring and environmental chemistry.

Chemical Classification and Particle Sizing of Foundry Sands

1985 ◽  
Vol 43 ◽  
pp. 388-389
Author(s):  
D.S. DeMiglio
Keyword(s):  
Image Analysis ◽  
Energy Dispersive Spectrometer ◽  
Image Analysis System ◽  
Representative Sampling ◽  
Foundry Sands ◽  
Large Atomic Number ◽  
Backscattered Electron ◽  
Sand Particles ◽  
Analysis System ◽  
Reclamation System

Much progress has been made in recent years towards the development of closed-loop foundry sand reclamation systems. However, virtually all work to date has determined the effectiveness of these systems to remove surface clay and metal oxide scales by a qualitative inspection of a representative sampling of sand particles. In this investigation, particles from a series of foundry sands were sized and chemically classified by a Lemont image analysis system (which was interfaced with an SEM and an X-ray energy dispersive spectrometer) in order to statistically document the effectiveness of a reclamation system developed by The Pangborn Company - a subsidiary of SOHIO.The following samples were submitted: unreclaimed sand; calcined sand; calcined & mechanically scrubbed sand and unused sand. Prior to analysis, each sample was sprinkled onto a carbon mount and coated with an evaporated film of carbon. A backscattered electron photomicrograph of a field of scale-covered particles is shown in Figure 1. Due to a large atomic number difference between sand particles and the carbon mount, the backscattered electron signal was used for image analysis since it had a uniform contrast over the shape of each particle.

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