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By Anna Gustafson, Sohail Manzoor, Håkan Schunnesson

Sublevel caving operation relies on the estimation of ore grade at drawpoints, as the mine management uses grade to decide whether the material at a certain ring should be loaded or abandoned. Grade is estimated in various ways, including visual estimation, density-based calculation, and sampling and assay methods. The grade estimation at the world’s two largest underground iron ore mines owned by LKAB in northern Sweden is based on the density difference between ore and waste. The calculations assume a constant swell factor, a theoretical fill of 100%, and a linear relationship between bucket weight and material grade. This study evaluated these assumptions in detail based on the loading data for 12,237 buckets and concluded that the method has some shortcomings which render the assumptions invalid. Further research is required to deal with these shortcomings to improve estimation of the material grade.

Oct 17, 2022

By Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

The depletion of good-quality phosphate resources, coupled by a need to supply acceptable products at a rapid rate, while meeting the specifications of fertilizer chemical plants, is of significant concern to the phosphate industry, particularly the production of concentrates with tolerable dolomite content. Tremendous efforts have been made in the past to develop an efficient and economical process that can effectively reject dolomite. However, dolomite removal continues to plague the phosphate industry due to several process-specific challenges being encountered with various beneficiation technologies. In this regard, detailed characterization of phosphate reserves is crucial to understand textural limitations and help design appropriate strategies to achieve quality products. In this paper, the development of procedures to establish dolomite rejection/francolite recovery curves for gravity preconcentration of pebble phosphate from Central Florida is described using high-speed X-ray computed tomography (HSXCT). The developed procedure is illustrated with the analysis of high MgO pebble phosphate samples (10.39 mm × 1 mm) received from South Pasture and Four Corners locations operated by the Mosaic company. The rejection/recovery curves were calculated for each sample for five different particle size classes to observe the trend in rejection/recovery with variation in particle size. In order to evaluate the reliability of the HSXCT data, analysis using the high-resolution X-ray computed tomography (HRXCT) technique was performed on one particular sample (FC-3-1). Finally, to assess the separation efficiency, the HSXCT and HRXCT rejection/recovery curves obtained were compared to experimental gravity preconcentration results reported in the literature. In this way, liberation limitations for gravity preconcentration in the processing of pebble phosphate have been established based on X-ray computed tomography analysis.

By P. A. Dimas

A new family of sulfide flotation collectors has been developed in our laboratory. These formulations are comprised of novel renewable materials combined with conventional reagents. The resulting diversity permits tunability of collector chemistry to meet a range of flotation problems. Several attributes of the new collectors are presented.

Jan 1, 2012

By Thomas E. Ban

During recent years fuel consuming industries of the United States have been caught between environmental restrictions and the uncertainty of obtaining an inexpensive fuel. With the advent of the National Energy Act of 1978 there has been added impetus to switch from gas and oil to coal. For industrial furnaces and boilers that were designed to bum coal, returning to an available compliance coal might be feasible. However, furnaces and boilers designed for gas or oil cannot reasonably be converted to coal unless the coal is initially gasified. All cases, nevertheless, depend upon the availability of an adequate structured coal of a compliance composition, a challenge to the coal mining industry. The foregoing problems have contributed to the current energy-coal crisis of today's economies. It therefore would be worthwhile to capitalize on previous experiences of the mineral processing industry.

Jan 1, 1979

By Adrian Coombs, Paul Magowan, Derek Zoldy

Continued development and intensification are fuelling the urgent need for new trunk infrastructure within The Regional Municipality of York and throughout the Greater Toronto Area. Permitting of these projects is increasingly subject to public scrutiny to severely restrict dewatering through construction technologies and the requirement for a comprehensive and effective Environmental Management Plan. Three current projects: one on the York Durham Sewage System and two in the City of Toronto 1.Conventional Design, Tender, Award: 4,150m (13,600 ft.) 2.7m (9 ft.) finished interior diameter soft ground tunnel for York Region’s YDSS Interceptor Trunk Sewer 2.Negotiated Contract: 3,800m (12,500 ft.) 3.5m diameter (11.5 ft.) rock tunnels for Enwave’s environmentally sustainable and innovative chilled water system in downtown Toronto 3.Conventional Design, Tender, Award: 2,200m (7,200 ft.) 3.3m diameter (10.8 ft.) rock tunnel for reinforcement of Hydro One’s primary hydro feed in the downtown core of Toronto These projects exemplify issues such as: EPB tunnel and sealed shaft technologies Substantial permitting requirements associated with dewatering Mitigation of rock creep Congested downtown rights-of-way Deep shafts and confined working compounds Unique scheduling and cost benefits when Owner, Contractor and Consultant can work together cooperatively.

Jan 1, 2007

By Daniel Brutto

"Environmental considerations are a key driver within marine mining consenting processes across different national and international legislative regimes and are critical in shaping the global public perception of the industry. As a result, it is vital that mining companies seeking to operate within marine environments establish a robust understanding of the sensitivities of the seabed environments in which they are active, the impacts of their activities and the ability of the environment to recover from these impacts. The significant risks of failing to do so include an inability to either obtain or maintain operating permits. At the individual project level, the environmental effects of any given development project are typically defined within the scope of an Environmental Impact Assessment (EIA). For well-established industries operating in well-studied environments this approach typically works well. However, where emerging industries or existing industries that are operating within new environments are concerned, there may be significant knowledge gaps pertaining to our understanding of how specific anthropogenic practices or activities interact with the marine environment. These knowledge gaps can cause significant uncertainties pertaining to the likely significant effects of a project. Such uncertainties may result in barriers to industry and economic progress, increased consenting risks, increased project costs to be borne by individual project developers through the acquisition of additional environmental data during the pre-consent or post-consent project phases, project delays and/or significant increases in environmental monitoring burdens with corresponding increases in project costs."

Sep 1, 2014

By J. H. Rowland

The Mine Improvement and New Emergency Response Act of 2006 (MINER Act) amended the Federal Mine Safety and Health Act of 1977 to improve the safety of mines. The MINER Act established a Technical Study Panel (the Panel) to provide independent scientific and engineering review and recommendations with respect to the utilization of belt air and the composition and fire retardant materials in underground coal mining (1). Because frictional heating is a common cause of belt fires, the Panel recommended that the Mine Safety and Health Administration (MSHA) evaluate the drum friction test to determine if such a test would contribute to conveyor belt safety beyond that provided by the Belt Evaluation Laboratory Test (BELT). This paper compares the results of the drum friction test to results from the BELT and large-scale tests for six different conveyor belts. The results are used to evaluate the drum friction test as a method to determine the fire resistance of conveyor belts.

Jan 1, 2011

By D. Kruse

Top down constructed large diameter (up to 90 m [300 ft]) shaft design and constructability issues present an interesting suite of challenges and opportunities highlighted in this paper. The study covers 2D and 3D finite element models used to: analyze various failure modes, evaluate the shaft liner and internal structures? response to seismic loading, assist in segment design, and assess final structural design tradeoffs. Efforts to achieve economic advantage over conventional heavy civil practices have prompted innovative solutions for ring and segment design, ring build assembly, and annulus backfill grouting. Intended for soft ground conditions, relationships between soil parameters and structure design are also explored.

Jan 1, 2011

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

A sociotechnical system (STS) creates a framework that allows an examination of how social and technical factors affect organizational outcomes within a specific environmental context. STS has been rigorously studied with a primary research focus addressing worker-technology interactions. Although these interactions are important, the social processes and interactions that occur whenever any technical or environmental change is introduced into the system have been undervalued. If social processes are better understood, mining organizations could efficiently prepare and stabilize for such changes. With this goal in mind, we sought to extend STS theory through applying principles of meta-design to analyze the results of two case study interventions. Specifically, we studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the Continuous Personal Dust Monitor) on factors within an STS including employees’ knowledge of, communication about, and use of technology to mitigate respirable dust sources. The results are presented in a way that first, addresses the overarching principles of meta-design STS including organizational participation, flexibility, and communication and second, examines how technology implementation processes differ when the organization is complying with a formal, higher-level requirement. Results show that a prominent focus on the social factors within an STS framework could help reduce unpredictability on the technical side and may improve communication within the system to help reduce adoption time, especially if and when accompanying a new, formal work process.

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

A sociotechnical system (STS) creates a framework that allows an examination of how social and technical factors affect organizational outcomes within a specific environmental context. STS has been rigorously studied with a primary research focus addressing worker-technology interactions. Although these interactions are important, the social processes and interactions that occur whenever any technical or environmental change is introduced into the system have been undervalued. If social processes are better understood, mining organizations could efficiently prepare and stabilize for such changes. With this goal in mind, we sought to extend STS theory through applying principles of meta-design to analyze the results of two case study interventions. Specifically, we studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the Continuous Personal Dust Monitor) on factors within an STS including employees’ knowledge of, communication about, and use of technology to mitigate respirable dust sources. The results are presented in a way that first, addresses the overarching principles of meta-design STS including organizational participation, flexibility, and communication and second, examines how technology implementation processes differ when the organization is complying with a formal, higher-level requirement. Results show that a prominent focus on the social factors within an STS framework could help reduce unpredictability on the technical side and may improve communication within the system to help reduce adoption time, especially if and when accompanying a new, formal work process.

By Klaus Rieker

The main train station of Leipzig in Germany is currently being upgraded from a head station to a partially thru station. In order to achieve this, significant ground improvements are necessary. Soil freezing for example is used to create the excavation box retaining walls. The freezing works will be carried out from two tunnels with an inner diameter of 2.4 m (~ 8ft). The tunnels were constructed by the pipe jacking method. The cutter head of the machine was equipped with discs and scrapers. Driving and excavation was carried out using a bentonite supported face. Due to the small arrival shafts, the machine had to be lifted out in components. The essential limitation of settlements during the drives was achieved even better than expected.

Jan 1, 2008

By C. Slotta, F. Charlier, P. Blomen

"Within the energy concept of the German government, the operating time of nuclear power plants was initially extended from about 8 to 14 years. It is planned, however, that every power plant will gradually be decommissioned until 2025 and that simultaneously the amount of renewable energies will successively be expanded. According to the political state, nuclear energy is a discontinued model. Looking at the global energy market, though, an obviously opposed development can be observed. At the moment, 443 nuclear power plants are running worldwide and further 62 facilities are being built. These about 500 nuclear power stations have to be supplied with nuclear fuel right now and in the future. The present paper will describe the worldwide use of nuclear energy, the extraction of the nuclear fuel uranium and in detail the available and predicted resources of uranium. The conclusion of the paper is the statement that uranium as nuclear fuel is no scarce resource but sufficiently available."

Jan 1, 2011

By Georgy Cherkashov, Svetlana Babaeva, Tamara Stepanova, Firstova. Anna

Seafloor massive sulfides (SMS) study in the Russian Exploration Area at the northern equatorial Mid Atlantic Ridge began after signing the contract with International Seabed Authority in 2012. In order to evaluate the SMS resources in the course of exploration the major and rare metals with economic value should be determined. The evaluation is based on geochemistry and mineralogy and particularly on the type of rare metals occurrence in the SMS. As a case study research of the Semyenov cluster of SMS deposits have been conducted.

Sep 1, 2014

By Felix E. Mutschler

Alkaline rock-related precious metal deposits include: • orthomagmatic platinum group elements (PGE) ± gold (Au); • porphyry copper-silver-gold (Cu-Ag-Au, ±PGE); • epithermal Au-only, and Au-Ag-base metals; • submarine exhalative Kuroko-, Cyprus-, seamount- and Yellowjacket-type deposits; and • enigmatic deposits akin to Olympic Dam. Coeval epithermal deposits related to porphyry deposits suggest the two types represent separate immiscible fluids evolved in oxidized, CO2-rich alkaline magma chambers. Alkaline rock provinces develop above mantle hot-spots, but crustal structures control the final distribution of magmas and ore fluids. Prospecting guides for alkaline rock-related precious metal deposits include the presence of evolved alkaline rocks, pervasive K-metasomatic, redox and carbonatic alteration and low level Au (±Te, etc.) anomalies. Although alkaline igneous rocks crop out in less than 1 % of the area of the North American Cordillera and craton, alkaline rock-related ore deposits have produced nearly 13% of the total United States and Canadian lode gold production. Large (31-t or 1 million-oz) deposits are common (Fig. 1), and additional deposits and reserves are being discovered. New genetic models are evolving, making alkaline rock-related precious metal prospects attractive exploration targets.

Jan 1, 1991

By S. A. G. Poppen, M. B. Mirza, A. I. Cooley

The U.S. Department of Energy (DOE) is responsible for siting and constructing a licensed geologic repository for commercially generated high-level nuclear waste. Within DOE, the Office of Civilian Radioactive Waste Management (OCRWM) Program has this responsibility. To accomplish this mission, the OCRWM Program is engaged in a multidisciplined effort to identify, qualify, and develop repository sites. The current strategy of the OCRWM Program is to identify candidate repository sites in basalt, tuff, and salt and to develop exploratory shafts at those sites. Within OCRWM, the Salt Repository Project Office (SRPO) identified the salt site for the development of exploratory shafts. The proposed Exploratory Shaft Facility (ESF) in salt will have several primary purposes. The shafts will provide access to the reference repository horizon to permit in situ testing of the salt horizons in order to satisfy the following data acquisition needs: • Verification of the salt repository design parameters and validation of performance assessment models • Demonstration of the constructibility • Capability to adequately seal penetrations into the salt An exploratory shaft is required by 10 CFR Part 60 for the conduct of in situ testing at depth prior to submittal of a license application for construction authorization of a repository. Therefore, construction of an ESF will also facilitate the licensing process.

Jan 1, 1987

By S. F. Diehl

Weathered mine waste consists of oxidized primary minerals and chemically unstable secondary phases that can be sources of readily soluble metals and acid rock drainage. Elevated concentrations of metals such as Cd, Cu, Fe, Mn, Ni, Pb, and Zn are observed in deionized water-based leachate solutions derived from complex sedex and Cu-Pb-Zn mine wastes. Leachate (USGS FLT) from the Elizabeth mine, a massive sulfide deposit, has a pH of 3.4 and high concentrations of Al (16700 ug/L), Cu (440 ug/L), and Zn (8620 ug/L). Leachate from the sedex Faro mine has a pH of 3.5 and high concentrations of Al (2040 ug/L), Cu (1930 ug/L), Pb (2080 ug/L), and Zn (52900 ug/L). In contrast, higher-pH leachates produced from tailings of polymetallic vein deposits have order of magnitude lower metal concentrations. These data indicate that highly soluble secondary mineral phases exist at the surface of waste material where the samples were collected. Sulfide minerals from all sites exhibit differential degrees of weathering, from dissolution etched grain rims, to rinds of secondary minerals, to skeletal remnants. These microscale mineral-dissolution textures enhance weathering and metal leachability of waste material. Besides the formation of secondary minerals, sulfide grains from dried tailings samples may be coated by amorphous Fe-Al-Si minerals that also adsorb metals such as Cu, Ni, and Zn.

Jan 1, 2011

By Keith Schaeffer

This paper presents a history of the planning, engineering and construction completed for the railroad tunnel crossing part of the West Elizabeth Avenue Storm Drainage Project, undertaken to relieve flooding within the West Elizabeth Avenue area in Linden, NJ. The Railroad Crossing Contract is part of the larger Linden Drainage Improvements Project consisting of a new gravity storm sewer system. The improvements are required to provide additional storm drainage for the City of Linden and the Merck Pharmaceuticals manufacturing facilities in the City of Linden.

Jan 1, 2008

By J. B. Rasmussen

As part of a purchase of a fleet of Caterpillar 785 trucks, Round Mountain Gold Corp., Cashman Equipment Co. and Caterpillar Inc. entered into a four-year contract for the major maintenance of the fleet of trucks. This contract includes fixed costs and guaranteed availability. The results have been excellent, and the fleet of trucks performs well. History The Smoky Valley Common Operation is a unique mine. Through a mixture of diligence and foresight, it has become the largest open-pit, heap leaching gold mine in the world. This was no small feat considering the remote area surrounding the mine. Round Mountain is located in north-central Nye County, NV. To the east of the town and mine lies the Central Toquima mountain range. To the west is the Toiyabe mountain range. Between them is the Big Smoky Valley, a flat expanse of sagebrush, salt grass and fine dirt.

Jan 1, 1991

By Steve Kral

Invensys is a London-based supplier of automation and control systems to a variety of manufacturing and processing industries. Through its global subsidiaries, Invensys provides customized, advanced process control systems and networks for automating industrial plants, including mineral processing plants. The company employs more than 80,000 people worldwide in its four divisions. They include Automation, Control, Powerware and Software Systems. These four divisions work together to design the complete package for their customer’s automation and process-control needs.

Jan 1, 2002

By Jack S. Greber

The mining industry generates an estimated 2.3 billion tons of solid waste each year and the total accumulated mineral resource solid waste at both active and inactive mine sites, approaches 30 billion tons. Five industries generate 85 percent of mine solid waste: copper, phosphate, iron, uranium, and coal. Over the past several years, the Federal government has shown increasing interest in the proper disposal of solid wastes generated by the mining industry. Three new pieces of federal legislation have been passed recently beginning with the most comprehensive regulatory authorization passed in 1976, the Resource Conservation and Recovery Act (RCRA) which has been amended to the Solid Waste Disposal Act Amendments of 1980. RCRA is implemented and enforced by the Environmental Protection Agency (EPA) and intended to control municipal and industrial solid wastes. Next came the passage of the Surface Mining Control and Reclamation Act (SMCRA) of 1977 which is implemented and enforced by the Department of Interior to control coal surface mining and the surface effects of underground coal mining, and finally, the recent Uranium Mill Tailings Radiation Control Act (UMTRCA) of 1978 implemented by EPA and enforced by the Nuclear Regulatory Commission (NRC) to control uranium mill tailings disposal.

Jan 1, 1981