List of Titles

Gold particle clustering : A new consideration in sampling applications

- Dominy, Simon, Platten, Ian

Authors: Dominy, Simon , Platten, Ian
Date: 2007
Type: Text , Journal article
Relation: Transactions of the Institutions of Mining and Metallurgy, Section B: Applied Earth Science Vol. 116, no. 3 (2007), p. 130-142
Full Text: false
Reviewed:
Description: Recent research indicates that an enhanced coarse gold problem may be present in some gold deposits. This can be due to the presence of gold particle clusters that give the effect of individual coarse-gold particles and leads to a high constitution heterogeneity (CH). These clusters, which may be distributed on the centimetre-scale or greater, give rise to high assay variability in field samples. However, once a sub-sample is pulverised, the effect of the clusters may be removed if the individual gold particles making up the clusters are liberated. Thus any resulting pulp will tend to have a low variability, unless true coarse-gold particles exist. Clusters are readily recognised in coarse gold deposits where they accentuate existing high nugget effect and CH. Clusters may however also occur in fine gold deposits where they produce an apparent coarse gold style. This is signaled by an unexpectedly high nugget effect from variography and poor correlation between field sample duplicates. The Gy sampling equation is applied to model coarse and fine gold deposits with clustered and non-clustered gold grains. Case studies illustrating observed effects of clustering are presented. If clustered particles exist, then proper protocol design at the field and early laboratory stage is paramount. The sample characterisation stage should include an assessment of possible gold article clustering, in addition to the standard descriptions of the gold particle size distribution. © 2007 Institute of Materials, Minerals and Mining and The AusIMM.
Description: C1
Description: 2003005555

Bulk sampling of complex gold deposits - material characterisation and program design and management

- Dominy, Simon, Platten, Ian, Xie, Y.

Authors: Dominy, Simon , Platten, Ian , Xie, Y.
Date: 2008
Type: Text , Conference paper
Relation: Australasian Institute of Mining and Metallurgy Publication Series, Perth, WA p. 41-57
Full Text: false
Description: Complex gold deposits are generally characterised by variable geometries, strong structural controls on grade distribution and a high-nugget effect. The use of diamond drilling and fire assays in this environment often results in an understatement of grade. Bulk samples are likely to be the closest estimators of true grade, and may be required to evaluate geological/grade risk during resource estimation/feasibility studies. Any bulk sampling program requires appropriate planning and implementation. The planning stage should attempt to delimit the extent and nature of mineralisation; characterise mineralogy and metallurgical properties of the ore; and define bulk sample size and how it will be sampled/processed. The approach to sample processing will be governed by the results of metallurgical testing and geological knowledge. Careful design of sampling protocols must be undertaken through material characterisation, understanding of gold particle sizing and the application of Gy's Sampling Theory.

Characterisation of in situ gold particle size and distribution for sampling protocol optimisation

- Dominy, Simon, Xie, Y., Platten, Ian

Authors: Dominy, Simon , Xie, Y. , Platten, Ian
Date: 2008
Type: Text , Conference proceedings
Full Text: false
Description: Sampling protocols that are designed to suit the mineralisation style will result in a reduction of the nugget effect and hence resource risk. The a priori need for all sampling programs is the effective characterisation of the mineralisation type(s) to support optimisation. This requires a program of sampling for sampling followed by holistic characterisation. At each end of the coarse-gold to fine-gold spectrum, the samplability of a deposit ranges from relatively simple for fine-grained disseminated gold particles, through to extremely difficult for coarse nuggety mineralisation. Many deposits contain a proportion of both particle size types. The proportion and size of coarse gold particles has a direct impact on the effectiveness of sampling, where coarser particles will require larger samples and more specialised protocols. The nature of mineralisation geology/mineralogy and associated gold particle sizing can only be determined by sampling to facilitate optimised protocols. Mineralogical studies, focusing on particle size, particle clustering and distribution in host minerals, are required as part of wider paragenetic and metallurgical investigations. This paper discusses the role of mineralogical studies in the characterisation of gold ores for sampling optimisation through a series of case studies.

Gold mineralisation and ore controls at the Clogau mine, Dolgellau, north Wales, United Kingdom

- Dominy, Simon, Platten, Ian

Authors: Dominy, Simon , Platten, Ian
Date: 2012
Type: Text , Journal article
Relation: Transactions of the Institutions of Mining and Metallurgy, Section B : Applied Earth Science Vol. 121, no. 1 (2012), p. 12-28
Full Text: false
Reviewed:
Description: At a recorded production of 2·5 t Au and mill recovered grade of 17 g/t Au, Clogau is the largest and richest mine in the Dolgellau gold-belt and is the most prolific gold producer in the United Kingdom. The main period of production commenced in 1861 and ended in 1911, with intermittent production between 1983 and 2007. The principal gold-quartz bearing Main reef can be traced for about 3 km along strike, trending approximately NE-SW and dipping between 60uSE and 90uSE. The reef system pinches and swells, changes strike, and splits into a number of major and minor branches. Reef width is variable, ranging from 6 m to a few centimetres. The reef is internally complex and composed of swarms of narrow sub-parallel quartz veins separated by sheets of country rock. The gold-bearing vein segments within the composite reef package are discontinuous, though may locally possess bonanza grades running at 1000s g/t Au. The predictability of the gold-rich segments is poor, but has been shown to be related to presence of the Clogau Formation (black-shale), interactions of the reef fault with greenstone sills, and/or reef splitting to form discrete ore shoots. © 2012 Institute of Materials, Minerals and Mining and The AusIMM.
Description: 2003010576

Grade control geological mapping in underground gold vein operations

- Dominy, Simon, Platten, Ian

Authors: Dominy, Simon , Platten, Ian
Date: 2012
Type: Text , Journal article
Relation: Transactions of the Institutions of Mining and Metallurgy, Section B : Applied Earth Science Vol. 121, no. 2 (2012), p. 96-103
Full Text: false
Reviewed:
Description: Grade control is a process of maximising value and reducing risk. It requires the delivery of tonnes at an optimum grade to the mill, via the accurate definition of ore and waste. It essentially comprises data collection, integration and interpretation, local resource estimation, stope design, supervision of mining and stockpile management. The foundation of all grade control programmes should be that of geological understanding led by clear and accurate mapping and representative sampling to drive appropriate estimation strategies and mining. Gold veins show features relating to erratic grade distribution (nugget effect), and variable geometry and internal architecture. These features include variations in dip, strike and width, late-stage faulting/shearing effects and vein continuity and type. Variations generally require close geological understanding to ensure optimum grade, minimal dilution and maximum mining recovery. A welldesigned grade control programme will prove to management and stakeholders that by applying geological knowledge, the mining process can be both efficient and cost effective. © 2012 Institute of Materials, Minerals and Mining and The AusIMM.
Description: 2003010686

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