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By Glenn Melchert, Paul Eger, Jon Wagner, Dave Antonson, John Folman

Current approaches to reclaiming acid generating tailings include permanent water cover or encapsulation with various synthetic liners and/or clay. Although these methods can be effective, some ongoing maintenance will be required in perpetuity to ensure that water levels are adequately maintained or that the integrity of any capping system is protected. The successful creation of wetlands in tailings basins offers the possibility of creating a stable environment for the tailings with minimal maintenance. Acid-generating tailings from a massive zinc sulfide deposit in Winston Lake, Ontario, were placed in small cylindrical tanks to examine the feasibility and effectiveness of creating wetlands and mitigating acid and metal release. Two uncovered controls were established in addition to the five treatments, which were done in duplicate. Each wetland tank was 117 cm in diameter and contained 6 1 cm of tailings. Treatments included 61 cm cover of wetland soil, 61 cm of glacial till, 61 cm of tailings, and two tanks with 71 cm of water. One of the water covers included the aquatic macrophytes: Elodea canadensis, Potamegeton sp., and Ceratophyllum demersum. Cattails (Typha latifolia) were planted in the plots with substrate cover, and the initial water level was set at ten centimeters. The pH within the tailings in the treated tanks generally ranged between 6.0 and 6.5 and zinc concentration ranged from 0.02 to 0.1 mg/L. The drainage from the controls had an average pH of 3.3, and 7,700 mg/L of zinc.

Jan 1, 2000

By John W. Wilson

INTRODUCTION In the past, the cost and time required for the construction of shafts has played an important part in the planning of underground mines. For reasons that are discussed later, the economics and technology of shaft construction in the future can be expected to play an even greater role in the planning of new mines and the operation of existing mines. Indeed, the very feasibility of a proposed mining venture may depend on the cost and timing of the shaft requirements. The most commonly used shaft sinking methods used today for excavating vertical shafts are discussed and the need for new technology and methods emphasized. In one study by the U. S. Bureau of Mines, it was reported that the coal industry in the United States alone could require 170 to 190 new shafts per year on the basis of doubling current production by the mid 1980's or 70 to 90 shafts on a more moderate coal production expansion program. This study concluded that the attainment of the required number of shafts would be unlikely with the present shaft sinking resources and costs. In order to meet the requirements for shafts in the United States coal and metal mining industries, more efficient and speedier shaft construction methods will be necessary. Current shaft sinking methods are, in the main, labor intensive, and it is noteworthy that it is becoming increasingly difficult to attract the work force required to sink shafts conventionally. Because of this situation, some attempts at mechanization have been made to compensate for this ever-increasing scarcity of trained

Jan 1, 1976

By Thomas Oberndorfer

Recent publications indicate that there is a rising interest in the field of mining method selection, and increasing efforts are being undertaken to develop satisfying solutions. Yet, computer assistance for mining method selection (MMS), or in other, terms assistance in the (pre-)feasibility state of a project, still lags behind the computer application in other mining activities. This is true for research as well as for application. This paper is intended as a contribution to the development in computer-assisted mining method selection, and focuses especially on underground hard-rock mining. It is structured in four main parts. The first deals with general aspects of mining method. selection within the process of mine planning, and with problems and requirements which derive from this specific situation. In the second part some numerical MMS-approaches hitherto published are briefly introduced, and investigations on these approaches are discussed. Based on .these experiences, in the third part an analysis of the complex system MMS is presented. It focuses on heuristics, influencing factors, objectives, assessment-routines and mining methods, and emphasizes the essential necessity of a profound mining method description (MMD) specially developed for the requirements of MMS and numerical processing. Accordingly the fourth part of this paper presents a mining method description model developed at the Department of Mining Engineering, Montan-University Leoben (MUL), Austria. It describes the consequences of the investigation, in particular the new mining method description model, on 'the design of a MMS-system. The paper closes with a outlook on the possibilities of an successful MMS-system being realised.

Jan 1, 1992

By Joseph R. Hatch

Previous studies of the Thompson and Temperly ore bodies show alteration aureoles in the Middle Ordovician host-rock limestones, dolomites and shales extending laterally as much as 60m from the ore. Thickness, texture, carbonate and clay mineralogy, major-, minor-, and trace-element contents; and carbonate carbon and carbonate oxygen Isotope compositions of the host rocks all have been significantly altered by hydrothermal processes. Organic geochemical analyses of samples from the basal 8-cm-thick carbonaceous shale bed and immediately overlying limestone bed of the Quimbys Mill Member of the Platteville Formation, collected from within the ore, the alteration aureole, and the unaltered country rock show: 1) solution of carbonates and residual concentration of organic matter, 2) decreases in the volatile (Si) and pyrolytic (S2) hydrocarbon yields In samples of the basal shale from within the ore, 3) decreases in the relative amounts of the lower molecular weight (<nC25) saturated hydrocarbons in samples from the ore, and 4) no changes in either the organic carbon isotope composition or the Rock-Eval or biomarker thermal maturation Indicators. In light of the 125-170°C depositional temperatures documented for the early marmatitic sphalerltes in these deposits by fluid Inclusion studies, the lack of thermal alteration of the organic matter suggests a relatively short mineralization episode, a conclusion supported by the relatively simple sphalerite band stratigraphy. The decreases in the volatile and pyrolytic hydrocarbon yields for shale samples from the ore supports a model for mineral deposition which obtains sulfide through reaction of brine sulfate and indigenous organic matter.

Jan 1, 2013

By J. R. Kunkel, V. Lishnevsky

At mine sites, the operational and required storage volumes of solution and water storage ponds and reservoirs are usually calculated based upon a water-balance approach. Many climatological variables including precipitation, air temperature, solar radiation, pan evaporation and relative humidity along with operating parameters, are used in the water-balance model. The water-balance model often seeks to find a “critical period” of wet or dry climatological sequences which result in a “maximum” pond storage volume or water demand. The problem with this approach is that the designer usually does not know when the project will come on line in relation to the historical record. To avoid this pitfall, we use a more robust approach. In the more robust method, the water-balance calculations begin in each year of the historic climatological record. This method results in the same number of water-balance runs (or realizations) as the number of years of climatological record. Results of this type of analysis guarantee that the critical period or maximum required pond volume will be found if it is assumed that the historical climatological record repeats itself or if a synthetic time series is used. In addition, this method permits calculation of the likelihood (probability) that a given pond volume will be equaled or exceeded in any given month of the operational life of the facility. In this paper, the results of the sizing of a heap leach pad solution pond are presented along with the probabilities of a given solution pond size being equaled or exceeded based on the robust water-balance approach.

Jan 1, 2002

By Peter G. Sechiari

The Rio Tinto-Zinc Corporation Limited (RTZ), through it exploration company Riofinex, commenced exploration for bauxite in the Amazonia region of Brazil during 1970. Following&apos; encouraging indications, exploration licences were taken out and an exploration programme was initiated In February 1975, a preliminary &apos;feasibility report indicated that a project, based on the Miltonia plateau located close to the town of Paragominas in the State of Para, was viable and that barging might offer an economic solution to getting the product to an ocean-going port. A, decision was taken in April 1975 to proceed with a full feasibility study. In the latter stages of the study, an engineering consortium of Mendes Junior and Bechtel do Brasil was employed to review, and modify if necessary, the concepts that RTZ had developed for the project&apos;s operation. With these concepts agreed, the consortium was requested to make capital and operating cost estimates, and these became available during February 1978. The deposit is being developed by a Brazilian company Mineracao Vera Cruz S.A. (MVC) in which the present share-holding is owned 64 percent by RTZ and 36 percent by Companhia Vale do Rio Doce (CVRD). RTZ is a British based international group of mining and industrial companies with interests in almost every major metal and fuel. CVRD is a Brazilian mining company, 85 percent owned by the Brazilian Government, with a major interest in iron ore and also other non-ferrous metals. It is intended, in due course, that the company will become majority owned by Brazilian interests.

Jan 1, 1979

By A. Mahmoudkhani

There has been a continuous interest in chemical aids for processing Canadian oil sands by hot water extraction process since the first commercial industry operation in 1967. Several inorganic and organic chemical systems have been introduced, of which sodium hydroxide is the most widely used extraction process aid by major producers. Use of NaOH, however, results in accumulation of sodium ions in recycled water, causing higher clays dispersion and producing tailings with poor geotechnical properties that turn into mature fine tailings. This is especially true for low grade and oxidized ores, which present the greatest challenges in bitumen recovery and produce the major portion of fine tailings. In this paper, we are presenting a novel method based on use of inorganic polymers as process aids for various low grade oil sands ores. Denver flotation cell and a laboratory scale hydrotransport loop were utilized to evaluate the effect of chemical dosage and operating parameters on the processability of oil sands samples from Athabasca region. Process tailings were examined for properties such as water chemistry, suspended solids, settling rate and the ease of tailing treatments. Our results demonstrate that the use of inorganic polymers during the froth process lead to a significant improvement in bitumen recovery from low grade oil sands and can improve further tailing treatments. This offers a viable solution that can be easily incorporated into current processing facilities and deliver several operational and economical benefits. Advantages in use of inorganic polymers versus sodium hydroxide are presented in details.

Jan 1, 2012

By L. Yuan, R. A. Thomas

"Atmospheric monitoring systems (AMS) have been widely used in underground coal mines in the U.S. for the detection of fire in the belt entry and monitoring of other ventilation-related parameters such as airflow velocity and methane concentration in specific mine locations. In addition to an AMS being able to detect a mine fire, the AMS data has the potential to provide fire characteristic information such as fire growth (heat release rate) and exact fire location. This information is critical in making decisions regarding fire-fighting strategies, underground personnel evacuation, and optimal escape routes. In this study, a methodology was developed to calculate the fire heat release rate using AMS sensor data for carbon monoxide (CO), carbon dioxide (CO2), and airflow velocity based on the theory of heat and species transfer in ventilation airflow. Full-scale mine fire experiments were then conducted in the Pittsburgh Mining Research Division (PMRD) Safety Research Coal Mine using an AMS with different fire sources. Sensor data collected from the experiments were used to calculate the heat release rates of the fires using this methodology. The calculated heat release rate was compared with the value determined from the mass loss rate of the combustible material using a digital load cell. The experimental results show that the heat release rate of a mine fire can be calculated using AMS sensor data with reasonable accuracy. INTRODUCTION Fires at different stages generate different gases and smoke toxicity hazards. When fires occur in underground mines, a significant amount of toxic gases and smoke enter the mine ventilation system and are carried throughout the mine ventilation network, increasing the hazard potential for personnel even if far away from the actual fire. Although fires that develop to the point of rapid flame spread pose imminent hazards, fires in their smoldering, pre-flaming stages can also contaminate the mine atmosphere with debilitating levels of smoke and toxic gases. The most important parameter for evaluating the fire hazard in mines is the heat release rate (HRR), which is directly related to the rate at which heat, smoke, and toxic gases are produced and transported by the ventilation system, and provides an indication of the time available for escape or firefighting [1]. The HRR is also an important input parameter to mine fire simulation models. Measuring the HRR of an actual fire can be a difficult task. Early experimental measurement of HRR focused on the heat output as represented by the temperature of the product gases. In ASTM E1321 (LIFT test), an array of thermocouples was positioned in a duct which captured all gaseous combustion products to measure their average temperature. This approach assumed the flow is adiabatic, which is never a reality. Significant progress on measuring HRR was made when Huggett showed that, for most common materials containing C, H, O, and N, the average heat release per unit mass of oxygen is 13.1 MJ/kg O2 [2]. Thus, the oxygen deficit is a measure of the HRR in the flow that the duct captures. This approach is termed oxygen consumption calorimetry (or the oxygen consumption method), and is widely used in the fire protection community."

Jan 1, 2017

By William A. Griffith

The recent recession has severely impacted the performance and results of virtually all of our natural resource companies. The depressing climate continues to linger and recovery maybe sometime away. Problems remain for resource companies in the steel and petroleum industries as well as the mining business. In February, at the AIME Annual Meeting in New York, an All-Institute session presented a variety of views on the situation. A. T. Yu, chairman of ORBA Corp., Mountain Lakes, NJ, organized presentations by top management personnel of four natural resource companies. This well attended session heard management strategems for the present and views for the future. A compilation and synthesis of these presentations, gathered by Dr. Yu, are presented here for ME readers. Leading off will be William A. Griffith, president and chief executive officer of Hecla Mining Co., Wallace, ID. Other speakers presented here include Wilfred P. Schmoe, executive vice president of Du Pont Co., Wilmington, DE; Frank W. Luerssen, chairman and chief executive officer of Inland Steel Co., Chicago, IL; and Adam H. Zimmerman, president and chief operating officer of Noranda Mines Ltd., Toronto, Ontario. First, then Griffith&apos;s remarks. Introduction The key to successfully managing a natural resource company in austere times is good management in good times. In other words, position the company during prosperous times to survive the times when the well dries up. Although we know how to manage properly, for various reasons we sometimes do not do it. We forget the lessons of history. We allow ourselves to be carried away by our egos. We fail to position our companies properly in good times. As a result, in bad times we find ourselves in deep trouble. We need constant reeducation in the things we already know. In the natural resource industries, proper positioning in good times involves becoming a low-cost producer, retaining the flexibility to pull in our horns, developing a lean and effective organization, and maintaining a healthy balance sheet. Nothing improves the chance of survival during austere times as much as being able to produce at a lower cost than your competitors. In our business, that means having low-cost mines - low cost because the ore bodies are high grade or favorably located, and because they are efficiently operated. It also means recognizing the competition. The key numbers are the cost to produce an ounce of silver or gold. Nothing else really counts. And our competition is every other precious metal mine in the world. Flexibility is important when one gets stuck with a high-cost operation, often because things do not work out as we expect. It is important to be able to shut down an operation quickly and easily, without high holding costs, and without disrupting the corporate organization. A lean and mean, effective organization of competent people is vital during bad times. A company will not have that if it is not developed and maintained during good times. Finally, a natural resource company has to develop a healthy balance sheet during good times if it is to survive the bad. Money in the

Jan 6, 1985

By Yun Bai, Sarah Wilson, Michael Salcher, Mark Trim

Over the last decade more than 62 miles (100 km) of civil transport tunnels were constructed in Sydney, Australia, using the sequential excavation method (SEM). The WestConnex motorway tunnels, each stage of which used over 20 roadheaders to excavate up to 40 tunnel headings, had numerous caverns up to 100 feet (30 m) wide and 82 feet (25 m) high. SEM tunnels in North America typically have far fewer active headings. This paper examines the differences in scope and risk allocation for construction phase services, including comparison of the Permit to Tunnel (PTT) process in Australia and the Required Excavation and Support process in North America.

Jun 23, 2024

By Ali Keneti, Xavier Ryan, Gerardo Sanchez, Shannon Goff

In this study, FLAC3D modeling was conducted for ground-structure stability assessment for a pilot tunnel passing under a large shaft excavated in the vicinity of existing structures at Karangahape Station for the City Rail Link Project in Auckland, New Zealand. The analysis involved generation of the geometries and construction sequences in Rhinoceros®, modeling the existing ground condition, calibration of the simulated in situ conditions with the observed behavior of the ground, and excavation of the shaft and the pilot tunnel. A comprehensive interpretation of the results was then performed accompanied by comparison of the predicted behavior with the observed response of the ground during construction.

Dec 1, 2022

A kinetic model for leaching of various metals with different lixiviants in a batch system has been developed. Material balances for reactants and products at the solid/liquid interface were formulated and solutions to these balances were obtained in view of practical conditions. Special emphasis has been given to examine mixed controlled reaction systems where both heterogenous reaction and mass transfer play important role on the overall rate expression. The resulting kinetic expressions for either powder or rotating disc are discussed in light of experimental findings for various metals. Examples of the metal dissolution systems considered in this study include cobalt, nickel, copper and gold in acid, cyanide or ammoniacal solutions.

Jan 1, 1992

By Horry Parker Jr, Jason Gillespie, Justin Kolster, Stephen O’Connell

Construction of the 5,932-ft Reedy River Basin Sewer Tunnel in Greenville, SC was marked by a critical transition from drill-and-blast mining in mixed-face conditions to TBM excavation with limited rock coverage. In this paper, we discuss the geological, geotechnical, and risk management considerations for transitioning to TBM operations in variably weathered gneissic bedrock. After construction of an unexpected 230-ft starter tunnel due to differing site conditions, the 11-ft diameter TBM was successfully launched in December 2019 without significant ground support issues. This project highlights the effectiveness of extensive rock probing to fully characterize bedrock topography prior to the TBM launch.

Jun 13, 2021

By J. O. Costello

Marble is a preferred surfacing material in up-scale buildings. Its use increased in the 1870&apos;s with rising national wealth and declined in the 1950&apos;s when synthetic materials for these applications were developed. Natural marble is now limited to high-end domestic and commercial structures. Cultured marble is a paste of white marble dust and polyester resin cured in molds yielding fixtures of specific finished dimensions. Dyes incorporated at different stages in the mixing cycle mimic shades and veining of natural marble. This paper discusses the filler requirements for cultured marble production and reviews new techniques to cut and finish natural marble.

Jan 1, 1999

By K. Hartman

Certain external forces affect the manner in which business is conducted. and in recent years changes in the business environment have altered how some of these external forces affect the management of a business. These changes must be understood and considered in definition of the strategy of the business. Implementation of the strategy must assure commitment from all departments within a company, and this commitment sometimes involves compromises to assure that a department&apos;s goals mesh with the overall business objective such compromises must be externally motivated. i.e. for benefit of the customer. Complete implementation transcends internal departments to all aspects of managing the efforts in the marketplace.

Jan 1, 1989

By J. Wyn Prior

The seismic refraction technique is probably the most popular geophysical method of bedrock profiling in geotechnical site investigations but is somewhat restricted by the inherent assumptions in the method. This paper describes how Hales&apos; method of profile interpretation is modified to overcome the assumptions of increasing velocity and layer thickness with depth when only first arrival data is available. A further expansion of Hales method enables presentation of refraction data in a form whereby bedrock features, such as changes in velocity, relief and dip in particular, are more readily recognized. Characteristic curves of the more common bedrock features are presented as an aid to bedrock feature recognition.

Jan 1, 1976

By John Carr

The tremendous growth in grinding mill size and horsepower during the &apos;70s demanded advancements in gear cutting technology and equipment for the &apos;80s. Computers are used as an aid in the design and selection of the mill drive system; sophisticated computer graphics are used to create manufacturing drawings; and a new generation of gear cutting machines are used to manufacture the gears. These new gear cutters can generate-cut gears over 40&apos; (12.2 m) in diameter at an AGMA quality level exceeding the currenty acceptable standards. The precision of the resulting gear assures maximum tooth contact, which will result in longer gear set life.

Jan 1, 1981

In its largest product launch in company history, Cummins Engines welcomed more than 200 customers, vendors and media to witness the unveiling of its new QSK95 engine at its Seymour Engine Plant in Seymour, IN on Nov. 1. It took the efforts of 150 engineers to design the QSK95 and more than $100 million in investments to establish a new production line and test facility at Cummins? Seymour Engine plant. The result of these efforts is a new platform of engines that Cummins says will provide as much as 2,983 kW (4,000 hp) and will be the most powerful, high-speed diesel engine ever built.

Jan 1, 2012

By E. J. Onuscheck

Coal mine safety of the past was plagued by disasters that took the lives of thousands of miners. Through the years new mining methods, improved laws, and a commitment from the mining industry has reduced the frequency of such incidents to a minimum. History tells us that coal was mined in the early 1700&apos;s in Virginia primarily for use by blacksmiths -- most of that mining was done in the Richmond area. It was in those mines that methane was encountered; as workings became more extensive, methane explosions became more frequent. In the early 1800&apos;s the first recorded explosion occurred near Richmond, Virginia -- 40 men were killed.

Jan 1, 1985

By Eric W. Johnson

In the late 1950&apos;s a low-grade copper ore zone was outlined at the fifty-year-old McIntyre Porcupine Mine in Northern Ontario. Following this an independent copper circuit was installed in the existing gold mill. The nature of the operation decreed that capital expenditure be a minimum. To this end, in order to resolve the problem of storing and grinding two separate ores, it was decided to install a divider in the existing 4000 ton capacity fine ore storage bin and to replace ten conventional feeders with sixteen Mexican feeders. The article describes a successful application of the Mexican type feeder.

Jan 1, 1968