Pearce, SR & McKay, K 2010, 'Rapid on-site screening for historic contamination at mine sites', in R Jewell & AB Fourie (eds), Mine Waste 2010: Proceedings of the First International Seminar on the Reduction of Risk in the Management of Tailings and Mine Waste, Australian Centre for Geomechanics, Perth, pp. 375-385, https://doi.org/10.36487/ACG_rep/1008_32_Pearce
(https://papers.acg.uwa.edu.au/p/1008_32_Pearce/)
Abstract: GHD and Newcrest Mining Limited (Newcrest) have carried out a large scale assessment of rapid on-site 
screening (ROSS) technology using a portable x-ray fluorescence (XRF) analyser (model type: Niton XL3T) 
as part of the Newcrest contaminated land assessment programme for expansion of a mine site. The XRF 
analyser was used to determine concentrations of metals across a number of old workshop and plant areas 
of the site to seek to delineate any potential impact in near surface soils and aid management decisions 
regarding both the scale of potential impact and the requirements for materials management. A dual 
assessment was undertaken in which traditional soil sampling and laboratory analysis was carried out in 
conjunction with in situ XRF sampling to allow a direct comparison between the two techniques. 
As would be expected the ROSS survey carried out proved to be significantly quicker than taking soil 
samples and dispatching to Perth for laboratory analysis, with an average sampling time of two minutes per 
sample location. This reduced sampling time allowed GHD to significantly increase the sampling density in 
comparison to conventional soil sampling. In addition, the XRF technology utilises global positioning system 
(GPS) information which, when used with a portable computer, allows the immediate download of data to 
geographical information software (GIS) and presentation of results on a geo-referenced map in the field. 
The turnaround time from data collection to data presentation using this technology is therefore reduced to a 
single day, allowing ‘real-time’ review and modification of the sampling strategy which would not otherwise 
have been possible using traditional laboratory based analysis. 
A robust understanding of the distribution of contamination on a given site is critically important when 
calculating volumes of material as part of materials management to avoid overestimating quantities of 
impacted material that may require separation or special treatment. The increased sampling density that can 
be achieved using ROSS when compared to traditional investigation techniques results in a more detailed 
understanding of the distribution of contamination both at the micro (or intra sample) and macro (or inter 
sample) scale, which will improve confidence levels with respect to calculating volumes of potentially 
impacted material. 
The study carried out by GHD and Newcrest indicates that in situ screening using ROSS for characterisation 
of contamination on a large scale mine site is valid and is cost and time effective at the investigation stage, 
particularly at remote site locations. ROSS offers potentially significant cost and time savings when carrying 
out works to delineate areas of impacted materials and will aid operational decision making with respect to 
efficient materials handling and waste management. In addition, the large sampling densities that can be 
achieved using the ROSS technique allows a more robust estimation of the distribution of contamination than 
can be achieved with a traditional laboratory based sampling programme of comparable cost.