How efficient are metal‐polymer and dual‐metals‐polymer non‐lead radiation shields?

Abstract Introduction Lead shields are often used to attenuate ionising radiations. However, to make lighter, recyclable and more efficient shields compared to lead, combinations of new metallic compounds together with polymer, for example, flexible polyvinyl chloride (PVC) have been developed recently. In this study, the capabilities of non‐lead radiation shields made of one or two metallic compounds and polymer were evaluated. Methods Monte Carlo (MC)‐based BEAMnrc code was used to build a functional model based on a Philips X‐ray machine in the range of radiographic energies. The MC model was then verified by IPEM Report 78 as a standardised global reference. The MC model was then used to evaluate the efficiency of non‐lead‐based garments made of metallic compound and polymer (MCP) including BaSO4‐PVC, Bi2O3‐PVC, Sn‐PVC and W‐PVC, as well as dual‐metallic compounds and polymer (DMCP) including Bi2O3‐BaSO4‐PVC, Bi2O3‐Sn‐PVC, W‐Sn‐PVC and W‐BaSO4‐PVC. The absorbed doses were determined at the surface of a water phantom and compared directly with the doses obtained for 0.5 mm pure lead (Pb). Results Bi2O3‐BaSO4‐PVC and W‐BaSO4‐PVC were found to be efficient shields for most of the energies. In addition to the above radiation shields, Bi2O3‐Sn‐PVC was also found to be effective for the spectrum of 60 keV. Bi2O3‐BaSO4‐PVC as a non‐lead dual metals‐PVC shield was shown to be more efficient than pure lead in diagnostic X‐ray range. Conclusion Combination of two metals‐PVC, a low atomic number (Z) metal together with a high atomic number metal, and also single‐metal‐PVC shields were shown to be efficient enough to apply as radiation protection shields instead of lead‐based garments

Re-Thinking Mining Waste Through an Integrative Approach Led by Circular Economy Aspirations

Mining wastes, particularly in the form of waste rocks and tailings, can have major social and environmental impacts. There is a need for comprehensive long-term strategies for transforming the mining industry to move toward zero environmental footprint. “How can the mining industry create new economic value, minimise its social and environmental impacts and diminish liability from mining waste?„ This would require cross-disciplinary skills, across the social, environmental, technical, legal, regulatory, and economic domains, to produce innovative solutions. The aim of this paper is to review the current knowledge across these domains and integrate them in a new approach for exploiting or “re-thinking„ mining wastes. This approach includes five key areas of social dimensions, geoenvironmental aspects, geometallurgy specifications, economic drivers and legal implications for improved environmental outcomes, and circular economy aspirations, which are aligned with the 10 principles of the International Council on Mining and Metals (ICMM). Applying circular economy thinking to mining waste presents a major opportunity to reduce the liability and increase the value of waste materials arising from mining and processing operations

Selective flotation of enargite from copper sulphides in Tampakan deposit

Recent research has demonstrated promising results showing the possibility of separating arsenic-copper sulphides from other copper minerals by controlling the potential of the flotation pulp. Most of these studies were conducted on single mineral systems, and the selective removal of arsenic-copper minerals in real ore systems is not well understood, particularly, the effects of mineralogical properties such as liberation and mineralogical association. In this study, two distinct ore samples, termed low arsenic sample (LAS) and high arsenic sample (HAS) were selected from the Tampakan copper-gold deposit in the Philippines, providing a range of arsenic levels. The selective separation of enargite from other copper sulphide minerals in a rougher flotation system under controlled pulp potential was investigated for both samples