Our 30 Seconds of Info videos are presented in Chinese, with English subtitles, by our Consultant Gregory Zhang. The videos are full of useful tips and technical tricks compiled by Ian Glacken our Geology Director and Paul Blackney our Principal Consultant. These videos cover Sampling, QAQC, Resource Estimation and Reconciliation.
Episode 3: What is the sampling contribution to the nugget effect?
Author: Ian Glacken – Geology Director ">
Video presenter: Gregory Zhang – Consultant ">
The nugget effect, as inferred from a variogram can have more than one component; the inherent nugget, which is a fundamental of the mineralisation and its uniformity (or lack thereof). The sampling error can influence the nugget effect of an orebody, and poor sampling practice, which can amplify and even swamp the ‘natural’ nugget.
References:
Chambers R L, Yarus J M, Hird K B. Petroleum geostatistics for nongeostatisticians: Part 1[J]. The Leading Edge, 2000, 19(5): 474-479.
Clark I. Statistics or geostatistics? Sampling error or nugget effect?[J]. Journal of the Southern African Institute of Mining and Metallurgy, 2010, 110(6): 307-312.
Episode 2: The correct sampling error (CSE)
Remember that some sampling errors cannot be eliminated, but they can be minimised.
Author: Ian Glacken – Geology Director ">
Video presenter: Gregory Zhang – Consultant ">
In addition to the Fundamental Sampling Error, which is the subject of Gy’s theory and its derivations, the Grouping and Segregation Error (GSE) is a function of the size, nature and constitution of the particles, among other factors. The GSE certainly can be reduced through judicious practice, but there are circumstances where the GSE can swamp other errors – you need to be aware of these.
References:
Glacken, I. Optiro Sampling course, 2020.
Gy P. Sampling of discrete materials—a new introduction to the theory of sampling: I. Qualitative approach[J]. Chemometrics and Intelligent Laboratory Systems, 2004, 74(1): 7-24.
Pitard F F. Theory of Sampling and Sampling Practice[M]. CRC Press, 2019.
Episode 1: Should you use Aircore samples in your Resource Estimate?
Author: Ian Glacken – Geology Director ">
Video presenter: Gregory Zhang – Consultant ">
If carried out to high standards, Aircore samples can approach RC in their level of representivity, although it is not suitable for all commodities and lithologies. It is always worthwhile looking at the relationship between Aircore and other sampling types (RC or DD) within an area where there is more-or-less equal representivity of both sample types; there should be no bias over the range of reasonable ‘ore-grade’ values.
Our internationally recognised team of geologists offer their expertise, skills and knowledge over the entire mining cycle. For more information about this video and our Geology Services please contact:
Ian Glacken – Geology Director ">
Gregory Zhang – Consultant ">
Diana Ross – Training Manager ">
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