SAMPLING , ANALYSIS AND LAB ASSAY
Fe – using the VIU formula , above , the selling price of the same ore for Facility A ( precision = 1 %, reported value 61.38 % Fe ) compared to Facility B ( precision = 0.16 %, reported value 61.901 % Fe ) will be as follows : n “ P ac ( A ) = 132.19 + ( -0.62 x 2.55 ) = $ 130.61 n “ P ac ( B ) = 132.19 + ( -0.0992 x 2.55 ) = $ 131.94 n “ P ac ( B ) - P ac ( A ) = $ 1.33 / t .”
Considering a standard shipment size of iron ore is 270,000 t ( dry ), Facility B would be able to charge $ 359,100 more per shipment of the same ore , according to Bruce .
“ Assuming this was the case for some of the iron ore majors producing plus-300 Mt / y , the difference would equate to over $ 400 million per annum variation in profits ,” he said .
Ten-fold returns
Ilpo Auranen , Chairman of IMA Engineering , has seen an uptick in demand for its sampling solutions in the last 12-24 months , with the mining community starting to realise the benefits that come with employing online measurement processes instead of traditional laboratory-based analysis .
IMA ’ s sampling products are seen across the mining spectrum – from drill core scanning to analyse grade and bulk ore sorting potential , to RC and blasthole drilling sampling for accurate 3D mine maps , to ore analysis on a conveyor ahead of the grinding mill / concentrator , to slurry and powder analysis within the process plant .
It is this breadth and depth of expertise that has led Auranen and IMA to conclude online mineral analysis is the only way for mining companies to get a real-time , accurate picture of their orebodies – which are , overall , much more heterogeneous than the industry appreciates .
“ The key is to be able to sample and analyse more frequently and accurately to know more about your orebody characteristics ,” Auranen said , explaining that traditional lab analysis and sampling processes do not facilitate this .
“ The investment mines make in sampling and analysis processes today represents less than 1 % of their total costs , but the value potential of these processes far exceeds that ,” he said . “ In most cases , you will get at least a 10-fold payback for effective online sampling and analysis investment .”
One solution offering such a payback is the company ’ s Autosampler for automated drill chip sampling on RC and blasthole drills .
Operated from the drill cabin or a remote control unit , this system automates the sampling , sample splitting and sample bag change process . It includes a highly accurate cone-type sample splitter and an innovative sample collection system to preserve the geological structure in the sample bag for detailed ore and waste boundary recognition and visual drill chip logging , the company said .
Not only does the Autosampler reduce the
inherent sampling bias and inconsistency that comes with manual blasthole / RC drill sampling processes , but it also addresses the operational health and safety issues this job entails .
“ Often what is forgotten in this manual process is health and safety ,” Auranen said . “ If you have ever been on the drill benches when they are drilling , you will appreciate there is a lot of dust in the air . In gold mining where the gold is in quartz veins , for example , you will have silica dust in the air from drill cuttings that can cause silicosis . It is a dangerous environment to work in .”
Working in such an environment also leads to inconsistencies in the sampling process , according to Auranen .
“ Often the sample is biased because the manual sampler doesn ’ t follow a prescribed process to take the sample due to the environment they are working in ,” he said . “ Every person carries out sampling in a different way .
“ If you automate this process , this sampling variability is eradicated .”
An Arctic gold mine recently progressed from testing the Autosampler to employing it in a commercial application on one of its blasthole drills . This is improving the accuracy of the company ’ s blasting process , with the knock-on benefits being higher gold recoveries , reduced waste tonnages reporting to the process plant and less tailings generation .
FEBRUARY 2022 | International Mining 77