A global rise in alluvial mining increases sediment load in tropical rivers.

Increasing gold and mineral mining activity in rivers across the global tropics has degraded ecosystems and threatened human health1,2. Such river mineral mining involves intensive excavation and sediment processing in river corridors, altering river form and releasing excess sediment downstream2. Increased suspended sediment loads can reduce water clarity and cause siltation to levels that may result in disease and mortality in fish3,4, poor water quality5 and damage to human infrastructure6. Although river mining has been investigated at local scales, no global synthesis of its physical footprint and impacts on hydrologic systems exists, leaving its full environmental consequences unknown. We assemble and analyse a 37-year satellite database showing pervasive, increasing river mineral mining worldwide. We identify 396 mining districts in 49 countries, concentrated in tropical waterways that are almost universally altered by mining-derived sediment. Of 173 mining-affected rivers, 80% have suspended sediment concentrations (SSCs) more than double pre-mining levels. In 30 countries in which mining affects large (>50 m wide) rivers, 23 ± 19% of large river length is altered by mining-derived sediment, a globe-spanning effect representing 35,000 river kilometres, 6% (±1% s.e.) of all large tropical river reaches. Our findings highlight the ubiquity and intensity of mining-associated degradation in tropical river systems.

Why did the use of antimony-bearing alloys in Bronze Age Anatolia fall dormant after the Early Bronze Age?: A Case from Resuloglu (Çorum, Turkey).

The archaeometallurgical and archaeological research carried out in Anatolia has provided numerous examples of diverse alloying practices representing different levels of societal interaction, from the extraction of ores to the trade of finished goods and high level gift exchange among elites. While discussions abound about the exploitation of mines, mining settlements, possible origins of artifacts, resources of copper, arsenic, and especially tin to improve our knowledge about Anatolian Bronze Age mining and metallurgy, uncommon alloying practices including the use of antimony, nickel, or lead have long remained in the shadows of scholarly research. With the aim of bringing attention to the diversity in alloying practices in Anatolian metallurgy, this article focuses on the use of antimony through an appraisal of archaeological and textual evidence from Bronze Age Anatolia. Archaeometric data from several Early Bronze Age sites are re-examined alongside new data emerging from Resuloglu (Çorum, Turkey) to explain the reduction of the variety of alloy types used. Portable-XRF analysis of artifacts from Resuloglu and mineralogical analysis of an antimony-bearing ore fragment present evidence of use of antimony at the region during the Early Bronze Age. This period is followed by disappearance of antimony in material record until the Iron Age, while textual records weakly refer to its circulation within the region. This paper considers geological, technological, and socio-economic factors to explain why the use of antimony alloys falls dormant after the Early Bronze Age. The political and economic change towards centralization over geological and technological factors is proposed as an explanation.

Historical reconstruction of Small-scale gold mining activities in tropical wetland sediments in Bajo Cauca-Antioquia, Colombia.

Global mining activities in Latin America have increased exponentially over the last decade. The present study aims to assess the historical impact of Artisanal and Small-scale Gold Mining activities (ASGM) in the Department of Antioquia, Colombia, a region characterized by increased mining development over the past century. Historical trends of heavy metals (i.e., Ag, Cr, Cu, Hg, Ni, Pb, and Zn) were reconstructed for the past century in a tropical wetland near the mining district. Results indicate that local mining operations did not have a significant influence in the area until the mid-20th century when metal concentrations began to increase and exceeded background values. The significant increase in both sediment accumulation rates and total organic carbon (TOC) content during the 1920s reflects the deforestation of the area due to the diversification of the economy (e.g. coffee cultivation, mining or animal husbandry). Both concentrations and accumulation rates of metals increased exponentially after the 1980s as a consequence of the reactivation of alluvial gold exploitation, reaching values that exceeded up to 2-5 times the background levels. The historical metal trends in sediments from Las Palmas wetland reflected the historical socio-economic development in Antioquia and can be used as a good proxy for evaluating anthropogenic impacts in this region.

Emerging Ergonomics Issues and Opportunities in Mining.

Ergonomics is the scientific discipline that investigates the interactions between humans and systems to optimize both human and system performance for worker safety, health, and productivity. Ergonomics is frequently involved either in the design of emerging technologies or in strategies to alleviate unanticipated human performance problems with emerging technologies. This manuscript explores several such emerging issues and opportunities in the context of the mining sector. In mining, the equipment, tools, and procedures have changed considerably and continue to change. Body-worn technology provides a number of opportunities to advance the safety and health of miners, while teleoperation and autonomous mining equipment stand to benefit significantly from ergonomics applications in other sectors. This manuscript focuses on those issues and opportunities that can impact the safety and health of miners in the near term.

High-temporal resolution landscape changes related to anthropogenic activities over the past millennium in the Vosges Mountains (France).

Iron mining activities in the Bruche valley (Vosges Mountains, France) date historically from the Roman period to the mid-nineteenth century. The geochemical and palynological study of a core from the peat bog of Le Champ du Feu allows highlighting impacts of these activities over the past millennium. Trace metal contamination is recorded for lead (Pb), arsenic, zinc, and antimony during the Middle Ages, the sixteenth century, and from cal. AD 1750-1900, with several sources distinguished by Pb isotope analyses. Forest exploitation is attested by the palynological analysis of the core, with exploitation of Fagus for smelting processes and cutting of Abies for agro-pastoralism. This approach highlights several patterns of contamination, corresponding to the mixing sources and the contamination intensity, which can be linked to the pollen assemblage zones. Hence, anthropogenic activities such as mining and farming led to long-term modification of the landscape composition in this mountainous area.

Uranium Mining and Norm in North America-Some Perspectives on Occupational Radiation Exposure.

All soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.S., these materials are sometimes referred to as technologically-enhanced naturally occurring radioactive materials (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertilizer. The processing of these materials has the potential to result in above-background radiation exposure to workers. Following a brief review of the sources and potential for worker exposure from NORM in these varied industries, this paper will then present an overview of uranium mining and recovery in North America, including discussion on the mining methods currently being used for both conventional (underground, open pit) and in situ leach (ISL), also referred to as In Situ Recovery (ISR), and the production of NORM materials and wastes associated with these uranium recovery methods. The radiological composition of the NORM products and wastes produced and recent data on radiological exposures received by workers in the North American uranium recovery industry are then described. The paper also identifies the responsible government agencies in the U.S. and Canada assigned the authority to regulate and control occupational exposure from these NORM materials.

A greener approach for resource recycling: Manganese bioleaching.

In view of unremitting diminution of mineral resources, rising energy economics along with increasing global consumption of Manganese (Mn), development of environment friendly technologies for tapping alternate sources of Mn has gained importance lately. Mn recovery from mining residues using conventional approaches is extremely expensive due to high capital and energy costs involved. However lean grade ores present in millions of tons awaits the development of competent and cost effective extractive process. Mn recovery by biomining with diverse microbes is thereby recommended as a superior and green alternative to the current pyro metallurgical techniques. The synergistic effects of different factors are known to influence microbial leaching of mineral ores which includes microbiological, mineralogical, physicochemical and process parameters. Bacterial bioleaching is mostly due to enzymatic influence, however fungal bioleaching is non enzymatic. Genomic studies on microbial diversity and an insight of its metabolic pathways provides unique dimension to the mechanism of biomining microorganisms. The extraction of Mn has a massive future prospective and will play a remarkable role in altering the situation of ever-decreasing grades of ore. This review aims to encompass the different aspects of Mn bioleaching, the plethora of organisms involved, the mechanisms driving the process and the recent trends and future prospects of this green technology.