Shaun Graham is part of the applications development team at Carl Zeiss Microscopy based in Cambridge. With a Masters in applied and environmental geology, he works in the geosciences, mining and oil & gas sectors to provide analytical solutions using scanning electron microscopy performed on mineral samples. This includes the provision of sample preparation equipment including a turbo-pumped coater from Quorum Technologies.
One of the main applications of the geosciences business, with its automated mineralogy software, is to provide data on mineral processing plant products from mining companies. It is vital that operating mines are able to track mineralogical and textural variation for processing and recovery optimizations. Recognising variability can save or make huge amounts of money to a company by maximizing yield and quality. The instrumentation has to be rugged and extremely reliable as it will often be located at the mine site itself. This has to be easy-to-use. Operators are not qualified scientists. They just require quick, accurate and actionable data to make informed decisions.
ZEISS supplies a special dedicated package to deliver to these requirements. This comprises sample preparation equipment and a “ruggedized” SEM. The system, known as MinSCAN, has been designed for this challenging environment, a mine-site mineralogy laboratory on wheels! A powerful data system takes the results to enable an increase in profits through greater concentrate quality and reduced losses to tailings (the materials left over after the process of separating the valuable fraction from the uneconomic fraction of an ore.). Being able to rapidly troubleshoot recovery issues, optimize plant performance and complement assays gives metallurgists, mine managers and superintendents the confidence to make effective decisions based on reliable, quantitative data.
Key to reproducible sample preparation is a Quorum Q150T providing high resolution carbon and sputter coating. Each 30 mm standard sample requires reproducible, uniform, thin coatings. Carbon coating is used in perhaps 80% of the applications where mineral particles are being investigated. For oil and gas applications, the ability of having a thin coating becomes most important when making porosity measurements. Uniform thinness will greatly reduce imaging artefacts. As Shaun says about the selection of Quorum coaters, “the Q150 series has been chosen based on its proven extremely reliable performance in what is usually a difficult environment far removed from the traditional research bench. The coater has to be available 24/7 as the failure to be able to coat a complete batch of daily samples in a day will risk loss of profit through the lack of actionable data from that days production. This is so important to our users that ZEISS supply, install and train users on all elements of the experimental process.”
Technical Director, Bob Morrison, says “Quorum has a long established track record as the preferred supplier of coaters for mining applications. Reliability is extremely important in these situations and we have been able to demonstrate the reliability and performance of the Q150T coater in our dealing with partners like Zeiss over a number of years.” The Q150T is available in three formats: sputtering, carbon evaporation or both. Depending upon the selected configuration, the Q150T can be a top-of-the-range sputter coater for high resolution scanning electron microscopy (SEM), a carbon coater suitable for SEM and transmission electron microscopy (TEM), or both – in a single easy-to-use system. Other options include metal evaporation and aperture cleaning.