Innovation is at the heart of the “green” revolution that focuses on mitigating the environmental impacts associated with mining, by reducing greenhouse gases, ecological footprints, chemical use and potentially harmful X-ray or nuclear emissions.
This focus spans the exploration phases all the way through to processing, and even includes the types of measurement and control techniques that are now being deployed inside concentrator plants.
While safer and eco-friendlier, these instruments, importantly, have also helped mines lower operating costs and increase their efficiencies, by sidestepping the onerous regulatory requirements associated with the use of traditional technologies, such as X-ray-based sources and nuclear densitometers.
Nuclear densitometers, for example, emit low radiation levels of typically 10 microSieverts per hour, which is similar to that of medical X-rays, and thus, the use thereof is restricted globally and governed by strict health and safety standards.
Restrictions include, for example, handlers requiring special mandatory training and having to undergo regular testing and skills development, while in some instances, designated radiology safety officers need to be appointed in areas where the technology is being used.
Special permits are also required to relocate the instrumentation, while additional costs are incurred in ensuring compliance with other onerous requirements associated with the safe transportation, storage and disposal of the technology.
This is in addition to the investment required in, among others, shielding and warning signage, as well as having to undertake periodic leak tests and inspections and undergo mandatory annual audits, all of which involves extensive record keeping.
Public sensitivity towards emittance technologies – exacerbated by incidences of missing equipment and even vehicle accidents when transporting these hazardous instruments – is also driving the pursuit by mining executives of safer and “greener” alternatives.
An example of a “greener” option is Rhosonics’ slurry-density meter, an ultrasonic system that measures the acoustic impedance of slurry in both dredging and mineral-processing applications.
Blue Cube Systems, a leading technology company that specialises in real-time in-line instrumentation for mineral processing, has also responded to the clarion call for more environmentally friendly alternative measurement and control technologies.
Its popular solution is based on diffuse-reflective spectroscopy, a tried and tested technology, which has also been used safely in agricultural and pharmaceutical industries.
Diffuse-reflective spectroscopy studies reflected and scattered light, which is a function of, among other factors, particle size and the vibrational characteristics of all the molecules and crystals in the surface material that is being scanned.
Blue Cube Systems’ propriety chemometric methods calibrate the optical spectra, including characteristic changes. Among these are the grade and percentage of solids that occur in a complex colour change.
While inherently safe and environmentally sustainable, the company’s solution has also overcome the existing limitations of typical X-ray-based on-stream analysers, by providing real-time in-line measurements that ensure cost, quality and throughput are within the targeted ranges.
Their maintenance costs are also significantly lower than X-ray-based on-stream analysers, which require extensive maintenance over time. With these, the mine also needs to hold an inventory of regulated replacement parts or wait for the supplier to provide or refurbish them.
Certainly, the implementation of more stringent international legislation governing the use of nuclear and X-ray-based instrumentation will place a further burden on mining process plants. This – in addition to the many benefits offered by solutions such as those offered by Blue Cube Systems – will drive increased interest in clean and green alternatives