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By Leo Gentile, David Selhorst

The $528 million Toledo Waterways Initiative (TWI) was implemented by the City of Toledo in 2002 and completed in August 2020. Toledo is one of many US cities required to implement a Long-Term Control Plan (LTCP) but one of few to have completed its plan. TWI consists of three storage and conveyance tunnels, four below grade storage basins ranging from 4 to 36 million gallons (MG), miles of sewer separation and interceptor improvements, green infrastructure and other appurtenant structures to dramatically reduce combined sewer overflows to the Maumee River, Ottawa River and Swan Creek. All three rivers flow into Lake Erie. The City’s 180-year history as a Midwest shipping, manufacturing and transportation hub provided design engineers and contractors no shortage of unknown underground challenges to complete the projects. The City will begin its 5-year Post-Construction Compliance Monitoring in 2021 to satisfy the final LTCP requirement. A program overview and experience from tunnel and underground basin construction in urban areas with buried active and legacy infrastructure will be discussed.

Jun 13, 2021

By K. Awuah-Offei, A. U. Rehman

"Information diffusion potential of a social media user affects how quickly information about a mineral project can diffuse through that user. If management can use social media and network analysis, in community engagement program, to understand how fast and how far information will diffuse to communities and followers of particular social media users, it can selectively focus on the most influential users. This paper proposes a method to examine the information diffusion potential of social media accounts. The work uses Gephi, an open source software, to extract and analyze data from different Twitter handles to predict their information diffusion potential. The work uses case studies of real Twitter users (e.g. mining news organizations and bloggers) associated with mining to illustrate the approach. The case study results show that there are significant disparities in information diffusion potential that will demand selective attention. This research will help mines develop effective social media engagement strategies. INTRODUCTION The mineral industry provides raw material for industrial activity to support our society (Martens and Rattmann, 2001). Mines have changed conventional mining practices to sustainable ones because of the negative impacts of mining and increased public awareness (Wang et al 2016). The concept of sustainable mining is getting mature as stakeholders (e.g., governments, investors and host communities) are getting involved in mining projects (World Economic Forum, 2014). The failure of mining companies to address the demands of these stakeholders might result in failure to acquire social license to operate (Thomson and Boutilier, 2011). The social license to operate (SLO), if granted, is mutually beneficial to all stakeholders. Mines prefer being granted SLO and keeping it to avoid any kind of social unrest due to their operation (Prno, 2013; Moffat and Zhang, 2014). Mining communities can grant different levels of SLO; ranging from withholding SLO to psychologically identifying with the project (Joyce and Thomson, 2000; Thomsan and Boutilier, 2011). Most of the previous work to understand community perceptions and SLO in mining is generally qualitative (ICMM, 2012a; Thomson and Boutilier, 2011; Prno, 2013; Moffat and Zhang, 2014; IFC, 2014). In particular, there is limited work on how community perceptions change over time due to information diffusion (Boateng and Awuah-Offei, 2017). However, SLO changes with respect to time (Yates and Horvath, 2013), which can result in risks that are not easy to predict. Mine managers and engineers have a desire to understand these changes so as to mitigate these risks (Que and Awuah-Offei, 2014; Que et al., 2015)."

Jan 1, 2018

By Deepak Malhotra

This paper discusses the need for periodic auditing of mineral processing flowsheets and the potential benefits a company can gain from a study of this nature. A carefully designed flowsheet auditing can have a significant impact on the metallurgical performance in the plant. Several case studies illustrating the potential benefits that can be attained from flowsheet auditing of mineral processing plants are discussed.

Jan 1, 1986

By A. K. Clarke

In any treatment process that requires a coarse feed material to be reduced to a fine size by crushing and/or grinding it must be determined whether a wet or dry comminution system should be utilized. All factors must be evaluated in reaching the decision. Among these factors are: 1) Ecology and Plant Environment: Unfortunately in many instances the decision on wet or dry is based on prejudice resulting from an unnecessary fear of dust. The writers submit that this fear, although once justified, is no longer valid because technology and equipment is now available to collect dust to meet any standard. When dry grinding is used it is very often possible to discard a portion of the waste product in a dry state. This will decrease the size of the tailing pond required. As pollution control standards increase it becomes increasingly difficult to clean up water from tailing ponds. 2) Operating Costs: Steel wear is often five or more times greater in wet grinding than in dry grinding. This is mainly due to corrosion. The evaluation of the economics of dry grinding must of course include the air system and dust collection; similarly in a wet grinding plant related pumping and material handling costs should be included. Pumping costs are often overlooked. This assumes water is made to flow for nothing. Pumping can account for 20 percent of the power consumption in the grinding plant. Large scale comparative tests were conducted in a wet and dry commercial plant in 1970. The same ore was used for both tests. With all factors included in both plants the dry system showed lower horsepower per ton.

Jan 1, 1971

By Yuanyuan Wang, XUEWEN WANG, Jinzhi Wei, Ligang Wen, Muxin Jia, Zhengyao Li

The abstract discusses the use of disodium carboxymethyl trithiocarbonate (D8) as an effective depressant in the flotation separation of stibnite and pyrite. The study investigates the mechanism behind D8's selective inhibition of pyrite, utilizing techniques like micro-flotation experiments, contact angle measurements, infrared spectroscopy, adsorption capacity analysis, and zeta potential measurements. The findings reveal that D8 physically adsorbs onto both pyrite and stibnite, but its adsorption capacity on pyrite is significantly higher. This adsorption enhances the hydrophilicity of the pyrite surface, hindering the adsorption of the collector and effectively depressing pyrite flotation, while having minimal impact on stibnite floatability.

Mar 14, 2022

By V. K. Reddy Kallam, NEHA PANDEY, Sunil Kumar Tripathy, ARIJIT BISWAS

The study investigates SO2 leaching of low-grade ferruginous manganese ores to selectively recover manganese as MnSO4 and produce battery-grade electrolytic manganese dioxide (EMD). The effects of leaching parameters (duration, temperature, SO2 flow rate) on Mn recovery were studied. Under optimum conditions, 97.9% Mn recovery was achieved. The MnSO4 leach liquor was purified and used for electrowinning EMD with 88.01% purity and battery-active γ structure.

Apr 20, 2022

By E. Yigit

Hydrometallurgical production of zinc from concentrates is generally carried out by H2SO4 leaching. For the smooth operation of this process, some harmful components must be removed from the leach solution before the electrolysis stage; MgO is one of these compounds. Zinc concentrate samples from the Mount Isa mines were used in leaching tests. Leaching tests with an aqueous solution of H2SO4 and SO2 gas were carried out at various temperatures, pH levels and leaching durations. While duration and the pH value of the solution were effective parameters in H2SO4 leaching, temperature and pH were more effective in SO2 leaching for the removal of MgCO3 and CaCO3. Removal of MgCO3 and CaCO3 was generally achieved at low pH values. The results show that SO2 gas can be a good alternative to sulfuric acid in the leaching of MgCO3 and CaCO3

Jan 1, 2010

By Y. J. Wang

This paper deals with the application of linear programming to the solution of mine ventilation network problems which involve only the controlled splitting of air. An airway whose air quantity is to be controlled to a prescribed value is called a "fixed-quantity" airway. In a network where the fixed-quantity airways are increased in number and are distributed such that the air quantities for the remaining airways are uniquely determined by Kirchhoff's first law, the problem reduces to determining the head losses and locations for air regulators and fans. This is one of the network problems encountered most often in underground coal mines. By formulating Kirchhoff's second law as a set of linear constraints and the total air horsepower supplied by fans as a linear objective function which is to be minimized, the problem is analyzed through the technique of linear programming. Some important properties of the problem are discussed and examples are presented.

Jan 1, 1971

By P. Schumacher, M. Fein

"INTRODUCTION Newmont’s Twin Creeks operation, part of its Nevada operations, produces gold from two large open pit mines. Mined ore is processed at one of three on-site facilities: a refractory mill with two autoclaves, an oxide mill and heap leaching facilities. Twin Creeks also processes various off-site sourced concentrates and ore including high grade underground ore from the Turquoise Ridge joint venture with Barrick Gold Corporation. This paper discusses Twin Creeks’ strategic mine planning process which is part of an in-depth continuous improvement program called “Full Potential.” The process involves cost analysis, phase design validations, life-of-mine production scheduling optimization, mill blending strategy and stockpile management. Through this Full Potential strategic planning, Twin Creeks is creating significant value by increasing near term free cash flow and life of mine net present value (“NPV”) and achieving cost reductions. TWIN CREEKS OPERATION Twin Creeks is one of the major gold producers in Newmont’s Nevada operations (see Figure 1, 2 and 3). Located approximately 15 miles north of Golconda, Twin Creeks produced approximately 28 % of the Nevada operation’s 2013 gold production of 1.8 million ounces (Newmont 2014). The production included Turquoise Ridge sourced gold ore from the joint venture (75% Barrick Gold Corporation, 25% Newmont).At Twin Creeks, there are two large open pits, named Mega Pit and Vista Pit (see Figure 4, 5 and 6). There are 3 to 5 phases in Mega Pit and 2 to 5 phases in Vista Pit depending on the gold price assumption. There is also an underground exploration project at the bottom of the Vista Pit. Twin Creeks produces gold from a variety of ore types requiring different processing techniques depending on economic and metallurgical characteristics. To ensure the best use of processing assets, engineering and processing groups at Twin Creeks utilize a Mixed Integer Linear Programming (“MILP”) model to guide the flow of mine sequences and material routing to various process facilities (Kawahata, Schumacher and Hufford 2013)."

Jan 1, 2015

By Luzheng Chen

The study aimed to evaluate the separation performance of a full-scale continuous centrifugal concentrator in the reconcentration of fine hematite from high-gradient magnetic separation (HGMS) concentrate in a tailings recovery plant, and to investigate the usefulness of the technology in industrial applications. The effect of changing the operating variables on concentrate grade and recovery was studied. The results indicate that among the variables considered in the study (water spray pressure, centrifugal acceleration, feed volume flow rate, feed percent solids and the reciprocation and spacing of water sprays), the change in centrifugal acceleration affects the recovery the most and continuous concentration can be achieved only when the water spray has a sufficient pressure. In addition, the reciprocation and spacing of the water sprays have a significant influence on the concentrate grade. Although performance of the full-scale concentrator is slightly inferior to pilot-scale trials, due to limitations in the scale-up design and the fluctuations of feed material characteristics, this concentrator provides a potential way to achieve continuous concentration and obtain a high-grade concentrate from tailings.

Jan 1, 2010

By A. G. Belova

With the federal climate change legislation in progress, there is a need for demonstration-stage technologies aimed at providing clean energy from coal. Our research aims to experimentally illustrate the feasibility of capturing CO2 on a novel sorbent system from a gaseous stream. The gas is then released resulting in a regenerated sorbent and a pressurized stream of pure CO2 to be used for storage. The proposed sorbent is a ceramic honey-comb structured monolith coated with CaO supported on a high-surface area alumina. CaO is a natural acceptor of CO2 and our design ensures the physical stability and chemical reactivity of CaO over a large number of CO2 capture/release cycles. Furthermore, the use of the monolith ensures a uniform flow through the reactor, minimizes pressure drop across the reactor, and maximizes the surface reactive area. In this paper, we will present the results from a flow-through laboratory-scale reactor that establishes the efficiency of the proposed system to capture CO2. Future applications of the reactor include integration within the new-generation coal gasification power plants, such as IGGC, as means of providing decarbonized electricity.

Jan 1, 2010

By Robert Stefanko

The Federal Coal Mine Health and Safety Act of 1969 had far reaching effects upon many aspects of mining, ventilation being no exception. In this paper, good ventilation procedures are briefly reviewed, and attention is focused on the changes brought about by the new Act. By way of illustration the ventilation system for a typical Pittsburgh Block system is developed and the requirements of the fan determined. This is then solved by an available computer program, and the application is evaluated. Figure 1 represents a projected system for a coal property 1 by 3 miles in plan at a depth of 1000 feet with a coal thickness of 6 feet and desired daily tonnage of approximately 7200 tons on a two-shift basis. Only one half of the mine is shown (north area) with a mirror image mining arrangement to be developed concurrently for the south area. Six working units are projected, three in each area, one on pillar extraction, another developing panel entries and a third on main entry development. A two-split system is used for each working section so that the continuous miner and bolting crews each have a separate split of air, and no equipment need pass through a line brattice. The old requirement of 6000 cfm at the last open crosscut has been increased to 9000 cfm, and for the first time a minimum quantity (3000 cfm) is stipulated at the face thus requiring either line brattice or an auxiliary fan. With the respirable dust requirement limited to 3 mg/m3, the use of a blower system is precluded and exhaust systems are virtually the only choice. Maintaining the line brattice within 10 feet of the working face at all times as required by the new law has a definite effect on the mining cycle and is most difficult at best. In the highly gaseous Pittsburgh seam located in south-western Pennsylvania and northern West Virginia quantities of 20,000 cfm per split are not uncommon to maintain the methane percentage below the required l%

Jan 1, 1972

By Kadri Dagdelen, Lee J. Zamalloa

Truck-shovel dispatch systems based on linear or nonlinear programming algorithms have been in operation since the mid-1980s, with different levels of success depending on the correct arrangement of operational resources and the complexity of the mine. These systems are known for shortcomings related to the logic behind the decision-making of the operational objectives. This makes it necessary to have a human agent (dispatcher) to guide the system when the operational parameters change, creating the possibility of suboptimal decisions due to the human factor. To address this issue, the present work discusses the implementation of a methodology based on artificial intelligence (AI) techniques to assist in the decision-making of the best optimization goals arrangement when operating a fleet management system. The focus of the analysis is on the evaluation of variable goal weights in a nonpreemptive, multigoal optimization model for multiple uncertain scenarios based on regions of optimal feasibility.

Apr 1, 2025

By K. Avarmaa, P. Taskinen

"The solubilities of rhodium (Rh) in a molten silver alloy in doré-smelting conditions for treating copper refinery slime at temperatures of 1,000 to 1,300 °C were measured using a high-temperature equilibration-quenching technique and direct phase analysis by electron probe X-ray microanalysis. The results obtained indicate that the solubility of rhodium in molten silver is very limited: only 0.04 to 0.26 weight percent at 1,000 and 1,300 °C, respectively. The thermodynamic properties of rhodium in molten silver were estimated from the solubility data. The compositions of the solid rhodium alloys in equilibrium with molten silver-rich doré metal were also measured in this study. The excess rhodium in the doré alloy will precipitate during the refining as solid, greater than 99 weight percent Rh.IntroductionSilver refining is a core step of the processes of anode slime treatment and precious metals recovery in copper refineries (Hait, Jana and Sanyal, 2009; Ludvigsson and Larsson, 2003). It separates the oxidic materials, such as nickel oxide (NiO) and barium sulfate (BaSO4), from metallics after the de-coppering and de-selenation steps of the anode slime, and refines the silver bullion from the undesired elements present (Cooper, 1990; Hyvärinen, Lindroos and Yllö, 1989). Doré metal is a silver-rich alloy which after the smelting step will be refined electrolytically, and the remaining constituents of gold as well as the platinum group metals (PGM) will be subsequently recovered in their own processing stages.Because of low concentrations of PGMs in copper, they are typically soluble in the doré metal in anode slime treatment. This can be concluded from their binary phase diagram data with silver (Massalski et al., 2007). One exception is sometimes encountered in the anode slime smelting operations if the smelter feedstock is rich in rhodium, as may be the case if the raw materials contain secondary raw materials such as e-scrap. The solubility of rhodium in solid silver is less than 0.04 weight percent (Królas and Sternik, 1995), and its solubility in molten silver is highly uncertain. The only experimental information in the literature (Królas et al., 1993; Elliott, 1985) suggests that the silver-rhodium alloy system at 960 °C forms a eutectic, which locates less than 2 °C below the melting point of pure silver (Arblaster, 2015). Early observations (Rössler, 1900) propose that rhodium is insoluble in molten silver even if solid silver-rhodium solutions have been recently produced on a nanoscale (Kusada et al., 2010).The aim of this study is to measure experimentally the solubility of rhodium in molten silver at doré metal smelting and refining temperatures. The silver alloy used to mimic the doré alloy contained silver and about 1 weight percent of the alloying elements copper, gold, palladium, rhodium and tellurium. The experiments were carried out in metal-slag equilibria with nitrogen-oxygen mixtures as the atmosphere, employing an equilibration-quenching technique and using direct phase composition analysis by electron probe X-ray microanalysis (EPMA) (Jak, Hayes and Lee, 1995)."

Jan 1, 2017

By Xuehui Li, Xinshuai Shi, Jun Wang, Jianguo Ning, Shang Yang, Zhaohui Zhang

Pressure relief is an important step in preventing and controlling rock burst disasters. Hydraulic slotting has emerged as a strategy for pressure relief and energy release in roadway surrounding rock. There is no qualitative description for the response relationship between hydraulic slotting parameters and the degree of pressure and energy release in a roadway, which is a scientific problem. In this paper, theoretical analysis, numerical simulation, and on-site industrial practice were comprehensively used. First, a structural model for the pressure relief and energy release of coal by hydraulic slotting in a deep roadway was established, and the pressure relief and energy release principle by hydraulic slotting was revealed. The principles and methods for determining hydraulic slotting parameters in the roadway were proposed. Three evaluation indices for the pressure relief and energy release effect of coal after hydraulic slotting were proposed, namely, the stress ratio of coal, elastic energy density ratio of coal, and displacement rate of the roadway rib. According to the evaluation indices, the degree of pressure relief and energy release was divided into three levels: reverse pressurization, full pressure relief, and transitional pressure relief. Then, a FLAC3D numerical model was constructed, the levels of pressure relief and energy release under different hydraulic slotting parameters were analyzed, and the optimal slotting parameters were determined. Finally, on-site industrial practices were carried out in Panel 7312 of the Xinhe Coal Mine. An effect test showed that the effect of pressure relief and energy release was remarkable after hydraulic slotting was adopted on the roadway surrounding rock, which can effectively reduce the risk of rock bursts. These research results can further improve hydraulic slotting technology systems and provide a theoretical basis and technical reference for the stability control of deep roadway surrounding rock.

Sep 20, 2023

The removal of tritium from tritiated water (-0.5 µCiIL) was studied by metallothermic reduction using aluminum. The influence of the three variables namely the aluminum powder amount, the NaOH concentration and the reaction time has been studied on the tritium activity reduction. The experimental results and statistical analysis showed that more than 85% of tritium can be removed from the tritiated water. Further work on the tritium recovery as well as efforts to totally decontaminate water by incorporating a cryogenic concept is currently pursued.

Jan 1, 1998

By Zhiyuan Shen, Dan Zhao

The abstract discusses the importance of reliable mine monitoring systems for preventing accidents. It focuses on diagnosing ventilation system failures caused by roadway faults that alter airflow resistance. The paper proposes using an improved Support Vector Machine (SVM) method to identify the fault location based on changes in air volume detected by wind speed sensors. The approach involves building a sensitivity 0-1 matrix and establishing a roadway fault scope library. The improved SVM method is tested on the Daming coal mine, demonstrating its effectiveness in diagnosing fault locations, reducing training time, and improving accuracy compared to traditional SVM.

Apr 5, 2022

By C. J. B. Dreyer

In terms of resources of amphibole asbestos only South Africa can be considered. There are only two asbestos producing fields, one in the Northern Cape Province producing only crocidolite and one in the Eastern Transvaal producing only amosite. The banded ironstone sequence in which amphibole asbestos occurs is discussed, and the genesis of the fibre is briefly reviewed. The properties and characteristics of amphibole asbestos are discussed and compared to those of chrysotile. Approximately 300,000 tonnes of amosite and crocidolite are produced annually. Crocidolite has a potential for a fivefold increase of production, which could be sustained beyond the year 2000. An estimate of the resources of the various producing fields in South Africa is made. Mining methods are reviewed and evaluation techniques discussed.

Jan 1, 1978

By J. K. Ahlness

The Bureau of Mines investigated technologies for determining the integrity of in situ leach mining wells. A self-contained trailer-mounted well integrity testing system (WITS) was designed and built to enable rapid testing of well casings for leaks as required by environmental regulations. The WITS utilizes two inflatable packers to seal off the entire casing length or any portion thereof. Water pressure is built between the packers to the desired test pressure, and the presence or absence of casing leaks is determined by monitoring the pressure drop between the packers. A winch and steel cable are used to run the packers in and out of the well. The WITS underwent an industry field test at the Irigaray in situ uranium leaching mine near Buffalo, WY. A total of 37 wells with an average depth of 225 ft (69 m) were tested at an average rate of four wells per 8-h shift with a two-person operating crew. This represents a 75-pct time savings and an 83-pct labor savings compared to the rigid-pipe method previously used at the mine, with which a three-person crew tested an average of one well per shift.

Jan 1, 1986

By W. K. Collins, C. L. Dahlin, D. C. Dahlin, W. K. O’Connor, G. E. Rush

Direct mineral carbonation has been investigated as a process to convert gaseous CO2 into a geologically stable final form. The process utilizes a slurry of water, with bicarbonate and salt additions, mixed with a mineral reactant, such as olivine (Mg2SiO4) or serpentine [Mg3Si2O5(OH)4]. Carbon dioxide is dissolved into this slurry, resulting in dissolution of the mineral and precipitation of magnesium carbonate (MgCO3). Optimum results have been achieved using heat pretreated serpentine feed material and high partial pressure of CO2 (PCO2). Specific conditions include: 155°C; P002=185 atm; 15% solids. Under these conditions, 78% conversion of the silicate to the carbonate was achieved in 30 minutes. Process mineralogy has been utilized to investigate the appropriate feed characteristics, identify the process products, and interpret the mineral dissolution and carbonate precipitation reaction paths.

Jan 1, 2001