Search

Water scarcity is a critical global-scale social risk. Several factors are affecting the availability of fresh water, like global population growth and the increase of industrial activities. Particularly in the mining industry, water is a critical resource for mineral production and road maintenance. Haul roads in surface mining operations are traditionally treated with large amounts of water to reduce dust emissions caused by large trucks that generate up to 97% of mine dust that reduces safety and mining productivity. An alternative to reduce dust in mining roads is the use of Magnesium Chloride Hexahydrate (6H 2 O·MgCl 2), which is a byproduct of the local lithium. So far, there is no scientific evidence that combines laboratory and field research to assess the effectiveness of an industrial byproduct used as a dust control for mining haul roads. This paper reports a quantitative analysis of the effectiveness of 6H 2 O·MgCl 2 in reducing operational water based on a laboratory and field study. Laboratory results show an important water retention effect in 6H 2 O·MgCl 2 treated soils compared to untreated soils. In addition, results showed that soils exposed to higher air relative humidity increases the water absorption from the air, confirming the hygroscopic property of 6H 2 O·MgCl 2. Field results collected for a year in a copper mine located in an arid area of Chile showed that water consumption in haul roads treated with water only is on average 153 times higher than water consumption in roads treated with 6H 2 O·MgCl 2 brine. In other words, 6H 2 O·MgCl 2 brine treatment allows approximately 99% of water saving. The dust monitoring system using a laser device demonstrated that, on average, dust emissions are 3.4 times higher in roads treated with water only than in roads treated with 6H 2 O·MgCl 2 brine. Overall, the study concludes that using 6H 2 O·MgCl 2 brine effectively reduces water consumption used for dust suppression in haul roads, demonstrating that the use of 6H 2 O·MgCl 2 byproduct is a very promising material for addressing water management issues in the mining industry. Image 10741 • Water is a critical and scarce resource for the mining industry. • Traditionally, water is sprayed on open pit mining roads to palliate dust emissions. • 6H 2 O·MgCl 2 byproduct brine reduced spray water consumption and dust emissions. • A 99% reduction of water consumption for dust suppression was achieved. [ABSTRACT FROM AUTHOR]

Abundant evidence suggests that the massive global exploitation of copper mines over the last two decades led to mine aging expressed as ore grade reduction, deepening of open pits and underground operations, hardening of the rock, and increasing stripping ratios. These processes have affected the evolution and change of key environmental footprint indicators. Copper ore grade decline seems the most important of these factors and depends on variables including the rate of extraction, ore deposit geological features, introduction of new technologies, the copper price and its co-products, and the discovery and exploitation of new ore deposits. From 2001 to 2015 Chile increased its copper production by 22% and produced overall 80 million tons of copper, more than it produced in the entire 20th century. This paper explores the effects of mine aging on three key environmental footprint indicators: energy and water consumption, and greenhouse gas emissions. Electric energy consumption per ton of copper should grow in the coming decade at a significantly slower rate than in the last fifteen years because of the slowdown of the ore grade decline in mill concentrators. Additionally, a steeper decrease is expected for the emission of greenhouse gases per ton of copper. [ABSTRACT FROM AUTHOR]

This paper investigates the relationship between international trade of avocado and the related virtual water trade over the period 2000–2016. Using a Physical Trade Analysis, we show that commercial and virtual water trade grew rapidly moving almost hand-in-hand in the years taken into account: in parallel with a remarkable increase of international trade of avocado from 0.4 Mt in 2000 to 1.9 Mt in 2016, the global virtual water trade of avocado increased from 408 Mm3 to 2238 Mm3 over the same period. The analysis emphasizes a large disparity between developed and developing countries, with the former being net importer of water and the latter large net exporter. In particular, large avocado-related water flows move from countries already under chronic water stress such as Mexico, Peru and Chile towards more water-rich regions such as US, Japan, Canada and the European Union. As a consequence, the overexploitation of water underlying the avocado trade flows may end up worsening environmental conditions in many relatively poor countries in which the export of avocado is often regarded as an important source of economic growth. • We study virtual water trade of avocado using Physical Trade Analysis over 2000–2016. • Avocado is mainly exported from water-poor to water-rich countries. • Large water flows move from Mexico, Peru and Chile to US, Japan, Canada and the EU. • Intra-European trade shows large re-exports from Spain and the Netherlands. • Export of avocado may worsen water scarcity in many relatively poor countries. [ABSTRACT FROM AUTHOR]