Determination of the sampling constant is an important step when applying the Fundamental Sampling Error equation to optimise sampling protocols. The classic method for its determination is based on the heterogeneity test (HT). In coarse gold-dominated mineralisation, the HT sometimes provides an evaluation of the fine-gold background grade population heterogeneity, but understates that of the important high-grade coarse-gold component. This is because the total mass of fragments is too small to represent the full gold particle size distribution of the mineralisation. Despite this, single heterogeneity tests (SHT) are often undertaken on deposits where the presence of coarse gold is ignored, not realised or understated. Resultant sampling and assaying protocols are frequently of poor quality and do not match the mineralisation characteristics. For coarse gold-dominated mineralisation, an empirical approach for sampling constant determination is recommended via direct estimation of the liberation diameter.
AfewuK. I. and LewisG. O.1998. Sampling a run-of-mine mill feed - a practical approach, Journal of the South African Institute of Mining and Metallurgy, 98, 299–304.
2.
Assibey-BonsuW.1996. Summary of present knowledge on the representative sampling of ore in the mining industry, Journal of the South African Institute of Mining and Metallurgy, 96, 289–293.
3.
BazinC., HodouinD. and BlondinR. M.2013. Estimation of the variance of the fundamental error associated to the sampling of low grade ores, International Journal of Mineral Processing, 124, 117–123.
4.
CarrascoP. C., CarrascoP. and JaraE.2004. The economic impact of incorrect sampling and analysis practices in the copper mining industry, Chemometrics and Intelligent Laboratory Systems, 74, 209–214.
5.
CarrascoP., CarrascoP., CamposM., TapiaJ. and MenichettiE.2005. Heterogeneity and Ingamell's tests of some Chilean porphyry ores. In:Proc. World Conf. Sampling and Blending, Melbourne: The Australasian Institute of Mining and Metallurgy, 139–150.
6.
CintraE. C., ScaboraJ. A., ViegasE. P., BarataR. and MaiaG. F.2007. Coarse gold sampling at Sao Francisco mine, Brazil. In:Proc. World Conf. Sampling and Bending, Porto Alegre: Fundacao Luiz Englert, 187–198.
7.
DominyS. C.2014a. Predicting the unpredictable - evaluating high-nugget effect gold deposits. In:Mineral Resource and Ore Reserve Estimation, Monograph 30, Melbourne: The Australasian Institute of Mining and Metallurgy, 659–678.
8.
DominyS. C.2014b. Effects of sample mass on gravity recoverable gold test results in low-grade ores, Appl. Earth Sci. (Trans IMM B), 123, 234–242.
9.
DominyS. C. and PetersenJ. S.2005. Sampling coarse gold-bearing mineralisation - developing effective protocols and a case study from the Nalunaq mine, Southern Greenland. In:Proc. World Conf. Sampling and Blending, Melbourne: The Australasian Institute of Mining and Metallurgy, 151–165.
10.
DominyS. C. and PlattenI. M.2007. Gold particle clustering - a new consideration in sampling applications, Appl. Earth Sci. (Trans IMM B), 116, 130–142.
11.
DominyS. C., AnnelsA. E., JohansenG. F. and CuffleyB. W.2000. General considerations of sampling and assaying in a coarse gold environment, Appl. Earth Sci. (Trans IMM B), 109, 145–167.
12.
DominyS. C., PlattenI. M. and XieY.2010. Determining gold particle size in gravity ores for sampling and metallurgical characterisation - discussion and test protocol. In:Proc. Gravity Gold Conf., Melbourne: The Australasian Institute of Mining and Metallurgy, 83–95.
13.
DominyS. C., PlattenI. M., HowardL. E., BellR-M., XieY. and MinnittR. C. A.2012. Determination of the sampling liberation diameter in a high-grade coarse gold ore by high-resolution X-ray computed tomography. In:Proc. Sampling Conf., Melbourne: The Australasian Institute of Mining and Metallurgy, 161–169.
14.
DominyS. C., PlattenI. M., XieY. and MinnittR. C. A.2011. Underground grade control protocol design: case study from the Liphichi gold project, Larecaja, Bolivia, Appl. Earth Sci. (Trans IMM B), 119, 205–219.
15.
DominyS. C., XieY. and PlattenI. M.2008. Gold particle characteristics in narrow vein deposits: implications for evaluation and metallurgy. In:Proc. Narrow Vein Mining Conf., Melbourne: The Australasian Institute of Mining and Metallurgy, 91–104.
16.
François-BongarçonD. M.1993. The practice of sampling theory of broken ores, CIM Bulletin, 86, 75–81.
17.
François-BongarçonD. M.1998a. Gy's formula: conclusion of a new phase of research, Australian Institute of Geoscientists Bulletin, 22, 1–10.
18.
François-BongarçonD. M.1998b. Extensions to the demonstration of Gy's formula, Exploration and Mining Geology, 7, 149–154.
19.
François-BongarçonD. M. and GyP. M.2002. The most common error in applying Gy's formula in the theory of mineral sampling and the history of the Liberation factor, Journal of the Southern African Institute of Mining and Metallurgy, 102, 475–479.
20.
GeelhoedB.2011. Is Gy's formula for the fundamental sampling error accurate? Experimental evidence, Minerals Engineering, 24, 169–173.
21.
GonzalesP. and CossioS.2007. A review of sampling protocol for a gold ore based on liberation study. In:Proc. World Conf. Sampling and Blending, Porto Alegre: Fundacao Luiz Englert, 163–174.
22.
GonzalesP. and DelgadilloJ. A.2011. Sampling protocols from heterogeneity tests on gold, copper, and polymetallic ores of Mexico. In:Proc. World Conf. Sampling and Blending, Santiago: Gecamin, 113–122.
23.
GyP. M.1979. Sampling of particulate materials, Amsterdam, Elsevier.
24.
GyP. M.1992. Sampling of heterogeneous and dynamic material systems, Amsterdam, Elsevier.
25.
GyP. M.2004. Sampling of discrete minerals - a new introduction to the theory of sampling, I. Qualitative approach, Chemometrics and Intelligent Laboratory Systems, 74, 7–24.
26.
JohansenG. F. and DominyS. C.2005. Development of sampling protocols at the Bendigo gold project, Australia. In:Proc. World Conf. Sampling and Blending, Melbourne: The Australasian Institute of Mining and Metallurgy, 175–183.
27.
LymanG. J. and SchouwstraR.2011. Use of scanning electron microscope to determine the sampling constant and liberation factor for fine materials. In:Proc. World Conf. Sampling and Blending, Santiago:Gecamin, 89–103.
28.
MagriE. J.2007. Some experiences in heterogeneity tests and mine sampling. In:Proc. World Conf. Sampling and Blending, Porto Alegre: Fundacao Luiz Englert, 329–348.
29.
MinnittR. C. A.2007. Sampling: the impact on costs and decision making, Journal of the Southern African Institute of Mining and Metallurgy, 107, 451–462.
30.
MinnittR. C. A.2014. A comparison of two methods for calculating the constants K and α in a broken ore. In:Proc. Sampling Conf., Melbourne: The Australasian Institute of Mining and Metallurgy, 165–178.
31.
MinnittR. C. A. and Assibey-BonsuW.2010. A comparison between the duplicate series method and the heterogeneity test as methods for calculating the sampling constants, Journal of the Southern African Institute of Mining and Metallurgy, 110, 251–268.
32.
MinnittR. C. A., François-BongarçonD. F. and PitardF. F.2011. Segregation free analysis for calibrating the constants K and α for use in Gy's formula. In:Proc. World Conf. Sampling and Blending,Santiago: Gecamin, 133–150.
33.
MinnittR. C. A., RiceP. M. and SpangenbergC.2007. Part 2: Experimental calibration of sampling parameters K and alpha for Gy's formula by the sampling tree method, Journal of the Southern African Institute of Mining and Metallurgy, 107, 513–518.
34.
PitardF. F.1993. Pierre Gy's sampling theory and sampling practice, Boca Raton, CRC Press.
35.
PitardF. F.2004. Effects of residual variances on the estimation of the variance of the fundamental error, Chemometrics and Intelligent Laboratory Systems, 74, 149–164.
36.
PitardF. F.2007. The in-situ nugget effect: a major component of the random term of a variogram. In:Proc. World Conf. Sampling and Blending, Porto Alegre: Fundacao Luiz Englert, 91–110.
37.
PitardF. F.2009. Pierre Gy's theory of sampling and C.O. Ingamells poisson process approach: pathways to representative sampling and appropriate industry standards. PhD. thesis. Aalborg University, Esberg, Denmark.
38.
PitardF. F.2015The advantages and pitfalls of conventional heterogeneity tests and a suggested alternative In: Proc. World Conf. Sampling and Blending, TOS Forum, 5, 13–18.
39.
RoyleA. G.1989. Splitting gold assay pulps containing coarse gold, Journal of the Leeds University Mining Association, 89, 63–68.
40.
RoyleA. G.1991. Safe sampling formulae for gold deposits, Min. Tech. (Trans IMM A), 100, 84–86.
