Green Low-Carbon Technology for Metalliferous Minerals

Metalliferous minerals play a central role in the global economy. They will continue to provide the raw materials we need for industrial processes. Significant challenges will likely emerge if the climate-driven green and low-carbon development transition of metalliferous mineral exploitation is not managed responsibly and sustainably. Green low-carbon technology is vital to promote the development of metalliferous mineral resources shifting from extensive and destructive mining to clean and energy-saving mining in future decades. Global mining scientists and engineers have conducted a lot of research in related fields, such as green mining, ecological mining, energy-saving mining, and mining solid waste recycling, and have achieved a great deal of innovative progress and achievements. This Special Issue intends to collect the latest developments in the green low-carbon mining field, written by well-known researchers who have contributed to the innovation of new technologies, process optimization methods, or energy-saving techniques in metalliferous minerals development

Novel and Emerging Strategies for Sustainable Mine Tailings and Acid Mine Drainage Management

Renewable energy and clean storage technologies are at the forefront of the world’s fight against climate change, including the UN-led move towards a carbon-neutral society. Because these complex technologies require more ‘critical’ metals and elements than fossil fuel-based technologies, the demands for raw materials in their manufacturing are skyrocketing and are projected to continue to increase into the foreseeable future.With ore grades on a steep decline, huge amounts of low-grade ores will have to be mined and processed to satisfy the world’s current and future demands for ‘critical’ metals and elements. Expansion of mining and mineral processing operations would mean more mining-related wastes—tailings, waste rocks and acid mine drainage (AMD)—notorious for their devastating and long-term destructive impacts on the environment. This Special Issue explored repurposing/reprocessing of tailings and AMD treatment cost reduction as promising alternatives to manage mine wastes more sustainably. It also includes articles on the critical roles of redox conditions and galvanic interactions on mine waste stability, hydrogeochemical controls on waste rock weathering, and climate change impacts on AMD formation in closed mines

Environmental Contamination by Trace Metals at the Inactive Pacific Mine Site, American Fork Canyon: Legal and Remediation Implications

Over the next decade, the environment will be the most important issue facing the minerals industry (Ary, 1990). Mining and its associated activities can be a source of considerable environmental damage (Table 1 ). Mining activities can cause surface and ground water pollution , damage the land and subsurface strata, and destroy terrestrial and aquatic habitat. While mining contributes to environmental degradation , it may be considered a necessary activity because it provides natural resources with a variety of commercial uses

CHARACTERIZATION AND DESULPHURIZATION OF REACTIVE MINE TAILINGS

A site-specific study is carried out to assess the suitability of froth flotation for desulphurization of reactive mine tailings with an Outokumpu flotation unit, type OK0.05 at the Musselwhite Gold Mine, Northern Ontario, Canada, to prevent acid mine drainage (AMD). Based on the data presented in this study, the maximum recovery of total sulphur was achieved when the operational parameters were set to the froth depth of 5 cm, air flow rate 125 L/min, impeller speed 1300 rpm and pulp density 35%. Another objective of this research is to develop a robust, rapid and easy digestion procedure for analysis of total sulphur in mine tailings using Inductive Coupled Plasma. It is found that the aqua regia (1 ml HNO3 + 3 ml HC1) digestion of 0.1 gm of samples for only 40 minutes of heating at 95°C produced fast, safe and accurate analytical results with a recovery of 97% for the selected reference materials

Studies of technogenic soils in Poland: past, present, and future perspectives

For a long time, the soils covering areas strongly transformed by human were ignored in scientifi c discourse. Also, practice did not care much about these soils because of their unproductivity. Only the large post-mining areas reclaimed and transformed into a forest or agricultural land were more interesting both for science and practice. In the case of post-mining areas the term “soilless land” was used for a long time, especially in relation to areas which were not reclaimed. In this paper, the past studies (until the end of 20th century) of technogenic soils in Poland were described. Technogenic soils of urban and industrial areas appeared in scientifi c considerations in Poland in the second half of the 20th century. In those times, soil properties on disposal sites were mainly investigated as a basic information for further design of technical and biological reclamation on disposal sites. Two Polish scientists should be emphasised as the world pioneers in concepts and studies of technogenic soils: (1) Michał Strzemski, who proposed a classifi cation scheme for soils in urban and industrial areas, as well as listed the tasks for future studies of these soils, and (2) Tadeusz Skawina, who focused on the dynamic and directions of the soil-forming processes on the mine spoils in the context of their reclamation. Moreover, studies of technogenic soils in the last two decades were also shown in the paper. From the beginning of the 21st century the scientifi c research gained momentum. Nowadays, Polish researchers have great achievements in studying technogenic soils, including investigation of their properties, genesis, evolution, classifi cation, biological features etc. Furthermore, we drew some outlines for future studies of Technosols

TREATMENT OF MINERAL-METALLURGICAL RESIDUES FOR THE RECOVERY OF USEFUL SPECIES AND THE REUSE OF PROCESS WASTE

Millions of tons of mining waste now represent a huge ecological challenge, perhaps also an economic opportunity. This paper illustrates and discusses an innovative approach in the reclamation of old mining areas, which is inspired by the principle of circular economy and considers the waste from old mining and mineral processing activities as potential secondary raw materials.The research proposes to apply the technique of flotation to extract from solid mining residues fractions of useful but polluting species, obtaining the double result of downgrading the material below the CSC (Contamination Threshold Concentration) and extracting a concentrate with commercial characteristics. The materials of potential interest are those of which the dumps from the cultivation and processing of the ores of Pb and Zn are composed. The establishment of the Centre of Excellence for Environmental Sustainability (CESA) has enabled an experimental activity based on the treatment of various mining residues in the Sulcis Iglesiente Guspinese area. The results obtained appear to be important in terms of both technological feasibility and costs compared to those of a Permanent Safety Deposit [1] [2]. The project has been developed, with reference to a pilot basin; the studies carried out so far have concerned samples taken from the Montevecchio Levante mud basin on which batch flotation tests were carried out for the reconstruction of a two-section plant flowsheet, one for the recovery of Zn sulphide and the second for the separation of the oxidized fraction from the final waste. Starting from feed concentrations around 2% Zinc, three products were obtained: a commercial Zn sulphide concentrate with 50% content; a final waste with heavy metal concentrations (Zn and Pb) lower than the CSC for industrial sites; and an intermediate concentrate (not marketable) whose residual Pb and Zn content requires inerting or disposal in a collection site. The collaboration with the Geological Survey of Finland (GTK), Europe's leading competence center for the evaluation and sustainable use of geological resources, has allowed the realization of a project aimed at the implementation of high quality data that have highlighted important characteristics of mineralogical composition of the treated material

Alaska mining and water quality

The Institute of Water Resources has sought financial assistance for some time in an attempt to initiate research relative to the impact of mining on water quality. Attempts were made as early as 1971 by Dr. Timothy Tilsworth and later by Dr. Donald Cook and Dr. Sage Murphy. These investigators anticipated growth in placer gold mining and the development of natural resources in Alaska during a period of national and environmental concern. The subsequent energy "crisis," the major increase in the price of gold on the world market, and dwindling nonrenewable resource supplies have resulted in large-scale mineral exploration in Alaska. This exploration, coupled with development of the trans-Alaska oil pipeline, has attracted considerable capital for potential investment and development in Alaska. Expected industrial growth has already started and major new projects are "just around the corner." Yet, as of 1976, no major research effort has occurred to determine the extent of or potential for water quality impacts from mining operations in Alaska. Recently a series of interdisciplinary research projects have been completed in Canada; however, the application of Canadian data to Alaskan problems is uncertain. Although, state and federal government agencies have been advised and are aware of this potential problem and lack of baseline data they have not sought out new information or rational solutions. Even now, with deadlines of Public Law 92-500 at hand, some regulatory agencies give the impression of attempting to ignore the situation. Interim limitations are proposed and permits are issued with no discernible rationale or basis. Data have not been obtained relative to the Alaskan mining operations and thus are not available for use in seeking solutions compatible with mining and environmental protection. Numbers appear to have been arbitrarily assigned to permits and water quality standards. When permits are issued, self-monitoring requirements are negligible or nonexistent. Nor have regulatory agencies demonstrated the ability or inclination to monitor mining operations or enforce permits and water quality standards. It was hoped that the project would bring together miners, environmentalists, and regulators in a cooperative effort to identify the problems and seek solutions. The investigators recognized the political sensitivity of the subject matter but proceeded optimistically. Relatively good cooperation, though not total, occurred early in the project. In April 1976, a symposium was held to exchange ideas and determine the state-of-the-art. Although the symposium had good attendance and an exchange of information occurred, the symposium itself was somewhat of a disappointment. With few exceptions, the participants aligned on one side or the other in preconceived fixed positions. Some even chose not to attend and were therefore able to avoid the issues. Little hard data was presented. Optimistically, some of the miners, environmentalists, and regulators are prepared to resolve their differences. This report, hopefully, will be of benefit to them. It is our experience that miners and environmentalists share a love of the land that is uniquely Alaska. We feel that technology is available for application to this problem for those who care about doing the job right in the "last frontier." Whether or not it will be effectively applied to protect Alaska's water resources is a question which remains unanswered.The work upon which this report is based was supported in part by funds provided by the United States Department of the Interior, Office of Water Resources Research Act of 1964, Public Law 88-379, as amended (Project A-055-ALAS)

A descriptive and quantitative approach regarding erosion and development of landforms on abandoned mine tailings: New insights and environmental implications from SE Spain

The San Cristóbal–Perules mining site in Mazarrón in southeast Spain was subjected to about a hundred years of intense mining activity for lead, silver, and zinc. Metallurgical operations (smelting, calcination, gravity concentration) carried out during the late nineteenth century–early twentieth century induced significant land transformation, and the most conspicuous wastes of this period consist of a chaotic piling of ‘old’ tailing deposits. Later on, during the mid-twentieth century, ‘modern’ tailings resulting from froth flotation were accumulated filling small valleys; these latter valley-fill tailings rose sequentially according to the upstream construction method, progressively raising the level of the dam during the process. Once abandoned, both types of tailing deposits underwent severe erosion, resulting in a mosaic of erosional and sedimentary landforms developed upon (e.g., gully formation) and within them (e.g., piping). We made an inventory and classification of these landforms. Our study shows the geomorphic work to reestablish a new steady state between the tailings deposits and the local erosive conditions. This scenario implies several hazards related to the extremely high heavy metal contents of these tailings and the geomorphic instability of the deposits. We also quantified the tailings tonnage and erosion that occurred at one of the tailings dams (El Roble). As shown by an oblique aerial photograph taken in 1968, this dam had a terraced topography, whereas in 2013 this morphology had evolved into a badland-type relief with deep parallel gullies. By recognizing and surveying specific, remnant points along the benches and outslopes of the older terraced topography, we were able to build up a first digital elevation model (DEM1) reflecting the initial topography. A second DEM, this time showing the present topography, allowed quantification of erosion via Material Loss = DEM1 − DEM2. This yields an erosion rate (1968–2009) of 151.8 Mg (MT) ha− 1 y− 1, which matches well typical values for erosion of mined areas, commonly above 100 Mg (MT) ha− 1 y− 1. Abandoned mine tailing deposits are extremely common in the semiarid scenarios of the SW USA, Australia, Chile, and Peru. Given the similarities of these scenarios with SE Spain, the example from Mazarrón may provide useful new insights regarding the erosion and geomorphic evolution of such tailing deposits. These matters should be addressed in key environmental actions such as mine closure plans and land reclamation projects. A solution may come via restoration of these deposits through landform design involving the building up of stable mature landscapes, which in turn can withstand erosion much more easily.Peer reviewe

Reflection, refraction, and rejection : copper smelting heritage and the execution of environmental policy

This dissertation examines the global technological and environmental history of copper smelting and the conflict that developed between historic preservation and environmental remediation at major copper smelting sites in the United States after their productive periods ended. Part I of the dissertation is a synthetic overview of the history of copper smelting and its environmental impact. After reviewing the basic metallurgy of copper ores, the dissertation contains successive chapters on the history of copper smelting to 1640, culminating in the so-called German, or Continental, processing system; on the emergence of the rival Welsh system during the British industrial revolution; and on the growth of American dominance in copper production the late 19th and early 20th centuries. The latter chapter focuses, in particular, on three of the most important early American copper districts: Michigan’s Keweenaw Peninsula, Tennessee’s Copper Basin, and Butte-Anaconda, Montana. As these three districts went into decline and ultimately out of production, they left a rich industrial heritage and significant waste and pollution problems generated by increasingly more sophisticated technologies capable of commercially processing steadily growing volumes of decreasingly rich ores. Part II of the dissertation looks at the conflict between historic preservation and environmental remediation that emerged locally and nationally in copper districts as they went into decline and eventually ceased production. Locally, former copper mining communities often split between those who wished to commemorate a region’s past importance and develop heritage tourism, and local developers who wished to clear up and clean out old industrial sites for other purposes. Nationally, Congress passed laws in the 1960s and 1970s mandating the preservation of historical resources (National Historic Preservation Act) and laws mandating the cleanup of contaminated landscapes (CERCLA, or Superfund), objectives sometimes in conflict – especially in the case of copper smelting sites. The dissertation devotes individual chapters to the conflicts that developed between environmental remediation, particularly involving the Environmental Protection Agency and the heritage movement in the Tennessee, Montana, and Michigan copper districts. A concluding chapter provides a broad model to illustrate the relationship between industrial decline, federal environmental remediation activities, and the growth of heritage consciousness in former copper mining and smelting areas, analyzes why the outcome varied in the three areas, and suggests methods for dealing with heritage-remediation issues to minimize conflict and maximize heritage preservation