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A computer simulation of the automatic control of continuous mining machines has been prepared, similar to previous simulations of longwall mining systems and coal thickness sensors. The simulation allows for programmed variation of the horizon detection method, the azimuthal guidance system, the type and configuration of the miner, varying hardness in the unmined face material (leading to varying error in the machine heading), and the miner's cutting cycle. It simulates control of the miner in three axes. Use of the simulator makes it possible to anticipate problems arising from the complex character of underground mining, which include unpredictable multi-pass coupling and unpredictable variation in geological conditions.

Jan 1, 1993

By G. Kim

The influence of bacterial growth phase on the flotation behavior of malachite has been investigated in a well-controlled Hallimond tube system. The microflotation tests were conducted for malachite (45?53 µm) using different amounts (bulk phase concentration=1×108?5×109 cells/mL) of Rhodococcus opacus (R. opacus) as a collector, which was grown at mid-exponential versus stationary phase, at a constant speed (340 rpm), pH (6), and malachite-bacteria interaction and flotation time (each 10 min). Hug differences between R. opacus cells in mid-exponential and stationary phase was observed from the results for electrophoretic mobility and flotation tests. Specifically, the isoelectric point of the cells in the stationary phase was lower than that in the mid-exponential phase, suggesting that the amount and distribution of surface functional groups onto cell surfaces are likely different. Additionally, the cells in stationary phase led to significant increase in the flotability compared to those in mid-exponential phase over the background bacterial concentration level of 1×108?5×109 cells/mL. Furthermore, the flotation efficiency tended to increase with increasing cell dosage for stationary phase cells while no distinct difference was observed for mid-exponential cells.

Feb 27, 2013

By Susumu Uchiyama

This machine was manufactured for excavation of the Roppongi station of the Tokyo Metro Line 12. This machine can excavate both the platform and the rail track at the same time in locations where the traffic is congested and has following features: A multi-centered TBM of the size of 7.06(H) x 13.18(W) m The world first H&V TBM, with right and left machine parts articulated vertically and separately for position control A large erector for simultaneous erection of column and central segments of special shape to construct a highly reliable tunnel This paper reports the design concept, construction, and work record.

Jan 1, 1999

By Adam H. Zimmerman

Introduction Noranda, like similar businesses, is suffering the pain of previously unheard of currency relationships, a cost structure built in better days, and conditions of gross oversupply possible in almost any commodity. Indeed, it does seem like the worst of all possible worlds is out there before us. To understand a Canadian natural resource company, you must know how the country is organized. So far as natural resources are concerned, Canada is not Canada. Canada is 10 provinces and each own the resources situated therein. Thus, the conditions of extraction, exploitation, and operation are all set by the province, while the conditions of trade and currency are set by the Federal government. This means that what may be the rule in Newfoundland may not be the rule in Manitoba or British Columbia. The second thing is that the Canadian currency has been a satellite of the US dollar for a long time. This means that we hold the unenviable and unjustified position of being the country with the second strongest currency in the world. What this has meant to us is what it has meant to an American operator. Since 1980, a pound of copper fetches 214% more for a Chilean than it does for us and a pound of zinc 115% more for a Belgian. From an American point of view, Canada is favored because its dollar is valued at 25% to 30% less than the U.S. However, because of industrial indiscretions in years past, Canada has a locked in labor cost disadvantage that is very hard to cope with. Canada has a unique situation with its labor unions. Many of the unions are, or have been, internationals and therefore gained undue strength in early days. Canada has a third political party of socialist persuasion. It is entirely funded by dues from laor union members. Thus, we have a politicized workforce. And finally, we have a public service that has the right to strike. This had made the public service unions by far the strongest now in Canada. What this means to the mining industry is that there is somebody out there blazing the trail. The unrelenting power of these public service unions probably creates a climate more conducive to excessive wage settlements in industry than would otherwise be the case. Study, Work, and Pray So what do we do when times get tough? In simple terms, we study a lot, we work harder, and we pray a great deal. We study a lot in terms of learning hitherto unknown strengths and weaknesses of our products, processes, and operations. We work hard in the sense that we do everything possible to improve our productivity. And we pray a lot because, so far, anything else we have done has not been enough. Some years ago, Noranda recognized that its principal base and precious metal operations were diminishing. To provide for the future, we should branch out into other resource type operations. These might be countercyclical and also perhaps a little more permanent. For this reason, Noranda entered the potash, aluminum, and forest products businesses. This, of course, was a 'brilliant' strategy that was much applauded in its early days. We built an excellent potash mine, the smallest inte-

Jan 6, 1985

By K. Wenrich

The uranium industry has made a dramatic turnaround in the past three years that even the most optimistic economist was not willing to predict during the uranium downswing of the 1990s. Uranium reached a 30-year low in February 2001 of $6.50/lb. By the end of February 2006 it had soared to $38.50/pound. This nearly 600% increase in the uranium spot price within 4 years dwarfed the increase in gold price that has barely mustered a 100% increase. The initial slow rise from $6.50 in February 2001 to $10.75 in April 2003 (fig. 1) was primarily driven by the decrease in the value of the dollar. Since then several factors have contributed to the soaring price: (1) The awakening of many to the simple fact that uranium supply has not met demand for several years and that the world’s stockpiles are being drawn down, (2) How sharply this fragile supply can be impacted by disasters at the world’s major uranium production facilities, such as a) the flooding of the McArthur River Mine in the spring of 2003, b) fires at Olympic Dam, c) the potential that Rossing, with an annual capacity of 4000 tonnes uranium might close by 2007, (3) the withdrawal of Tenex from the HEU (highly enriched uranium) feed agreement, and (4) the announcement by the Chinese of their intent to build 30 new nuclear reactors.

Jan 1, 2007

By Omid Asghari, Amin Mousavi, Arshad Ranjbar

Geometallurgical modeling of the production benches is an attempt to estimate the geometallurgical variables of the different ore domains, which leads to a better understanding of the ore and its properties. Having geometallurgical variables results in a more accurate prediction of ore characteristics, an improved drilling and blasting operation, and better efficiency of the processing plant. In this research, the geometallurgical variables required for the geometallurgical modeling of the extraction benches are discussed. Then, the relations between Bond work index (BWi), as one of the most important geometallurgical variables and the primary grindability index, and rock geomechanical properties are investigated based on the previously published studies. The BWi is the main parameter for measuring the resistance to the grinding of ore minerals. It represents the energy required for processing (e.g., crushing, grinding) ore rocks in the beneficiation plant. As a real case study, BWi of a production bench in Sungun Copper Mine, located in East Azarbaijan province, Iran, was estimated. The rock’s geomechanical properties were measured using laboratory tests, including uniaxial compressive strength, Brazilian tensile strength, point load strength, and hardness. Then, BWi was estimated using the proposed formulas in the literature and the results of the rock’s geomechanical properties. The selected bench consists of three ore zones and two dyke domains. The laboratory tests revealed that the first ore zone has a slightly higher compressive strength than the other two zones, while the compressive strength of the waste rocks is larger than the ore domains. Using the proposed equations in the literature, the predicted values of the BWi for the samples in ore zones are in the range of 6.36 – 14.44 (kWh/t), and therefore this wide range must be considered when the short-term production schedule is planned. In addition, variations are observed in the samples within a specific zone and between the ore zones, demonstrating heterogeneity in the selected bench. Finally, wide-open results obtained by different equations show a necessity to perform a geometallurgical program specifically for the Sungun mine.

Oct 28, 2021

By A. Bieg, M. Samson, Z. Bell, A. Zinsser, J. Schuyler

As the world progresses toward the renewable energy transition, the demand for minerals increases exponentially. According to the International Energy Agency (IEA) 2021 Net Zero by 2050 Report, critical mineral production needs to grow six times to combat climate change. It’s estimated that four to seven percent of global greenhouse gas (GHG) emissions come from the mining sector’s Scope 1 and 2 (direct and indirect) emissions. Including Scope 3 (upstream, downstream, and embedded) emissions, the sector accounts for 28% of global GHG emissions. In a typical mining operation, diesel fuel is the biggest source of direct GHG emissions, and haulage is often the main source of diesel emissions. Large haul trucks have been the industry standard for over 50 years and offer flexibility, relatively low capital cost (especially with equipment lease options), and guaranteed technology with known maintenance. The challenge will be to justify their continued use when there are more economical options that lead to significant reductions in GHG emissions. The purpose of this study is to compare five haulage options in terms of GHG emissions, using the methodology defined by the Greenhouse Gas Protocol Scopes 1, 2, and 3 (Category 2). Additionally, this analysis compares operating and capital costs associated with the five haulage options (emerging and proven technologies): 1) Diesel-Electric Haul Trucks, 2) Battery-Electric Haul Trucks, 3) Fuel Cell Haul Trucks, 4) Railveyor, and 5) Conveyor. This analysis looks at the emissions and costs associated with operating the equipment (fuel and electricity), the embedded emissions and costs associated with the construction and installation of the equipment itself, and the associated infrastructure (roads, powerlines, and rail).

Feb 1, 2023

By J. P. Rider

The number of extended cut mining systems has increased significantly in coal mines over the last decade, and there is a constant push to extend the face ventilation systems to even greater setback distances. The need to maintain airflow at setback distances of 12.2 m (40 ft) and beyond requires that methods for delivering intake air to the face be improved, or alternative ventilation techniques be implemented. The emphasis of this research effort was to examine various techniques to improve the distribution of available air at the mining face in order to reduce face methane levels. A study was conducted comparing the performance of a jet fan, used in conjunction with a machine mounted scrubber, with blowing curtain ventilation in a 27.5 m (90 ft) heading. In addition, a second study was performed on blowing curtain systems examining how scrubber flow, intake air velocity, and curtain setback influence face methane concentrations. Results showed that when the heading advances to a depth of 27.5 m (90 ft) blowing curtain systems were more efficient at diluting face methane levels when compared to a jet fan. Also, increases in scrubber flows and curtain velocity resulted in lower face methane concentrations for blowing curtain systems at 9.2 and 15.2 m (30 and 50 ft) setbacks.

Feb 24, 1997

By Judy B. Jones, Bradley A. Crenshaw, Theodore DePooter

This paper reviews groundwater issues leading to a secondary grouting program at the Chattahoochee Tunnel that was implemented subsequent to the contact grouting program. The secondary grouting program was developed based on infiltration data, geology, and testing programs. This paper includes a brief description of the geological features encountered, as well as describing the grouting program. The success of this grouting operation has been quantified by several methods, and is presented to help others project the costs and benefits of this type of program. Review of initial results and refinements of techniques are also discussed.

Jan 1, 2005

By Christos Roumpos, Philip‑Mark Spanidis, Francis Pavloudakis

Coal mining operations are large-scale, long-term frameworks of high complexity. Mining organizations accumulate, develop, and leverage knowledge from diverse scientific and technological fields as a result of these operations. Both practical experience and existing literature indicate that knowledge management (KM) methods within the mining industry primarily target solving immediate technical challenges and operational requirements. However, they are not commonly regarded as strategic tools to enhance the performance and competitiveness of mining companies. Empirical evidence from the Greek mining industry suggests that the management of available knowledge is intricate, less effective, and dysfunctional. This paper presents a methodology based on the principles of quantitative research (QNR), collaboratively conducted with a group of mining experts, to assess the KM landscape in the Greek mining industry. The methodology involves a structured data collection framework using questionnaires, subsequent statistical analysis, a discussion on critical methodological aspects, and an interpretation of results focusing on key aspects useful for planners and designers of KM systems in the mining industry. Finally, the paper concludes by summarizing the methodology’s outcomes and proposing further perspectives for research.

Mar 16, 2024

Pillars with width to height ratios of less than 1.0 are frequently created in underground hard rock mines. The strength of slender pillars can be estimated using empirically developed equations. However, the equations can provide variable results when the width-to-height ratios approach 0.5. This paper investigates some of the issues affecting pillar strength at low width-to-height ratios in hard brittle rock. The investigation includes an evaluation of empirical pillar strength data presented in the literature and observations of pillar performance in underground limestone mines in the eastern United States, supplemented by numerical modeling in which failure processes and sensitivity of slender pillars to variations in rock mass properties are evaluated. The results showed that the strength of slender pillars is more variable than that of wider pillars. The numerical model results demonstrated the increasing role of brittle rock failure in slender pillar strength. The absence of confinement in slender pillars can result in a fully brittle failure process, while wider pillars fail in a combined brittle and shearing mode. The onset of spalling in slender pillars occurs at or near the ultimate strength, while this is not the case for wider pillars. Slender pillars are shown to be more sensitive to the presence of discontinuities than wider pillars, which can partly explain the increased variability of slender pillar strength. Two examples are presented, which illustrate failure initiation by brittle spalling and the sensitivity of slender pillars to the presence of discontinuities.

Jan 1, 2006

By Stephen M. Smading

Unique onsite assembly of a 12.43 m Main Beam TBM and back-up system was completed on September 18, 2008 in the remote mountains of the Sichuan province of China. The equipment was assembled onsite, without previously having been assembled and tested in a factory, utilizing a method called Onsite First Time Assembly (OFTA). The Jinping-II hydroelectric project features four parallel headrace tunnels approximately 18 km long, two of which will be excavated by TBMs and two by drill and blast. A nearby fifth tunnel is being excavated by a 7.2 m TBM to draw down ground water in advance of excavating the headrace tunnels. This paper addresses the following topics: ¦Project description including geology and terrain; ¦The decision process leading to onsite first time assembly, the assembly process and logistics, and lessons learned; ¦Design features of the TBM and back-up system; and ¦Operational history from startup to the writing of the paper.

By C. J. Roos

Ground-engaging tools are used to prevent damage to the main components of earth-moving equipment. These tools consist of everything from shovel teeth to replaceable drill bits to dozer wear plates. The costs of these "consumable" items are increasing with the costs of raw materials. This project developed a tool to be used by Newmont Mining Corp. to predict the consumption of excavator teeth at a particular mine site. This paper presents the results of the Montana Tech research project in which an equation was developed to predict excavator teeth consumption based on production rates and rock properties.

Jan 1, 2010

By George A. Mealey

Caving mining methods that are based on a planned caving of rock above and/or at times surrounding the material being mined can be classified in three broad categories: longwall mining, sublevel caving, and block caving. Each of the three methods involves a distinct technology as well as art of operation. Each requires a relatively large, regular, and predictable ore body. As a rule, the effect of mining results in some form of impact or change on the surface. Operationally, underground caving methods are characterized by high productivity as well as a high percentage of extraction of the mineral being mined. A key element for the productivity of this form of mining is the ability to standardize the various elements of work taking place underground. Therefore, work-men may perform a specialized role rather than function as all-around miners. Further, the nature of the mining methods lend them to a high level of mechanization. Operations and manpower can be centralized into a relatively small area where supervision can be concentrated and therefore be more effective. Productivity as well as safety benefits thereby. The caving method is unique in that the exploitation openings are deliberately destroyed by the process of mining. Rock mechanics principles focus on the ensurance and the propagation of the cave as well as the continuance of the mine openings designed to extract the broken ore. As a rule, production operations are designed to maintain a steady, continuous flow of ore from the extraction areas. This steady flow rather than an intermittent flow tends to promote good caving action as well as reduce hangups.

Jan 1, 2008

By M. H. Basiri

The application of aluminum matrix composites, due to their unique properties, is significantly growing in the variety of industries such as aerospace and automobile. In comparison to other light metals, such as magnesium and titanium, aluminum is lower in price. These are the advantages that this metal dominates the others. In this research, first by applying the lost foam casting method, the SiCp/A356 composite was cast in the bottom and side gate conditions with 690°C and volume fraction of 10%. Furthermore, the effects of reinforcement particles (60 µm, 75 µm) were examined. The results present the particles distribution in the side gate methods is more homogeneous than the bottom gate casting method. Also, by increasing the particles sizes, the fading rate in the side gate are reduced from 22% to 19%, as well as from 26.4% to 25.4% in the bottom gate. Key words: Carbide-Silicone Particle, Gating System, Composite Micro-Structure, Foam Casting

Feb 27, 2013

By Terry M. Tilley, Gregory P. Sherry

Purpose This is a unique project because the mining and tunneling industries have become highly mechanized and cannot normally accommodate a project where surface disturbance must be minimized or eliminated when there is less than 10 feet of ground cover. More traditional less mechanized methods must be employed and the skills and techniques for accomplishing the work have become all but non-existent. Therefore, this article highlights those areas of specialized skills and techniques. Methods The article will describe the design approach, the method(s) of ground support selected, the method(s) of excavation selected, the planning, scheduling and materials selection process. In addition, the article will describe the actual production characteristics and the results of the project. This approach will concentrate on productivities, adaptations to actual conditions and the quality of the end product. The design approach basically was to insure that the temporary support methods were adequate for the excavation and shoring stage of the project. The final concrete liner was designed using conventional structural design methods with the goal of constructing a tunnel that will last 100 years. The methods of support were spiling and variations of spiling in order to provide advance temporary ground support. In this project spiling is steel channel cantilevered and driven into the ground ahead of the working tunnel face which supports the ground allowing the face muck to be removed with overhead protection’. Conclusion This will be a discussion of the applicability of the methods. The actual performance of the excavation and shoring methods will also be evaluated. The final concrete liner completion results, the actual production rates and the conformance with budget and schedule will be addressed.

Jan 1, 2005

Impala Platinum?s No.16 Shaft mine is currently under construction and is expected to reach full production of 256 500 tons per month by 2014. Mining will start at 1 260 m below surface with a maximum mining depth of 1 535 m where virgin rock temperatures of 56.6°C will be experienced. As a result of depth, high virgin rock temperature and narrow reef mining, an expected total of 31.5 MW[R] of air cooling capacity will be required to achieve acceptable underground conditions. This will be achieved by cooling mine intake air in a single dedicated air cooling installation located on surface. The compact installation includes air cooling spray chamber, refrigeration machines, condenser cooling towers, evaporator and condenser water reticulation as well as all electrical and control systems. Construction and commissioning of the first phase of this air cooling installation has recently been completed on a turn-key contract basis.

Jan 1, 2009

By Lane White

In mid-April 1992, MINING ENGINEERING mailed a survey questionnaire relating to mining shovels and hydraulic excavators to 125 SME members working at surface mines or at the headquarters of companies that operate surface mines. The mailing was directed to individuals whose titles indicate that they have management or mine planning responsibilities for surface mining operations. A total of 56 usable surveys returned by June 17 are the basis of this report. Precious metals mines Eighteen precious metals mines or mining companies returned completed surveys in time to be included in this report. Of these, 14 use hydraulic shovels only for both ore and waste, I uses both hydraulic and rope shovels, and 2 use Caterpillar 988 front-end loaders for both ore and waste. (Of the latter 2, neither expects to be in the market for a shovel in the next three years. I of these 2 placed Harnischfeger P&H number one and O&K number two in response to the question, "Based on your current knowledge of their machines, which manufacturer would you likely chose to supply new shovels or excavators to a mine or mines operating under your responsibility, if you were in the market?") Another uses front-end loaders, make not designated. The latter does not expect to be in the market for mining shovels or excavators within the next three years. Of the final total of 14 precious metals mines using only hydraulic excavators to load ore and waste, 8 use Hitachi excavators only, 1 uses Demag excavators only, 1 uses Liebherr excavators only, 1 uses O&K excavators only, 1 uses Harnischfeger P&H and O&K excavators, 1 uses Harnischfeger P&H and Hitachi excavators, and 1 uses Hitachi and Demag excavators. Of the 14 precious metals mines using only hydraulic excavators, 7 use excavators in the 7.6 to 11.5 m; (10 to 15 cu yd) size range. Of these 7, 5 use only excavators in this size range, and they are used to load both ore and waste. 1 of the 7 also uses 11.5 to 17 m' (15 to 22 cu yd) excavators, and I also uses a 17 to 23 m3 (22 to 30 cu yd) excavator. Of the 7 remaining of these 14 precious metals mines that use only hydraulic excavators, 3 use 11.5 to 17 m' (15 to 22 cu yd), 2 use 17 to 23 m3 (22 to 30 cu yd), and 2 use less than 7.6 m' (10 cu yd) units.

Jan 1, 1992

The introduction of computer technology to the mining industry has produced many benefits for the mining engineer. The most significant is the dramatic increase in productivity realized by the individual user. This is important during times of competitive market conditions. Software for the minerals and energy industries has evolved substantially over the past decade. But even today it remains difficult to find a system that features the flexibility and integration capabilities to effectively (and cost-effectively) handle the needs of professionals in each phase of the mining industry - from exploration to reclamation. Several national software developers are now addressing this challenge. One Denver-based company, MINEsoft Ltd., offers a software package that is currently being used in each phase of the mining industry. The basic technology used in MINEsoft's database management system was developed in the 1960s. But during these early years of the computer industry, most of the technology was available only on mainframe computers, and then only as separate entities. MINEsoft's system unifies these various systems in one package that can be used on most computers manufactured today. Database Management System TECHBASE is a flexible, integrated database management system designed specifically for technical applications. The system features a database manager with no practical limit to the amount of data it can store, retrieve, and manipulate, according to the company. TECHBASE in¬cludes Applications Packages (TAPs) designed to meet the needs of professionals in a host of industries. Clients use the TECH BASE system to prepare many reports, including important EPA information. The package reduces data to a manageable level and enables users to increase productivity with a smaller staff. Mining engineers no longer need to do things by hand. What used to be a day's work can be accomplished in an hour or two. Exploration "Using the TECHBASE system to generate maps has probably saved us the expense of three or four draftsmen," says Ralph Fitch, regional manager and senior staff geologist with Chevron Resources in Portland, ME. "The system has great flexibility. You can treat it much like a spreadsheet. If you are halfway through with a particular project, the system allows you to add fields and calculations with ease but without starting over." Fitch uses TECHBASE for the "straightforward" plotting of results and generation of geochemical and geophysical profiles. "In exploration," he says, "these are the two key elements ... the generation of maps and data profiles. The system allows you to plot as many elements and variables in these areas that you like." Other aspects are important, too, says Fitch, including drill hole sections. "We use all the basic capabilities the system provides in the complete package," he explains. "When shopping for a system, TECHBASE was clearly dedicated to exploration in the

Jan 9, 1987

By P. A. Plunkert, D. E. Morse, L. McCartan, J. F. Papp

The mineral sector is a fundamental part of the U.S. economy. It contributes to the real gross domestic product (GDP) at several levels — basic (mining), intermediate processing, manufacturing of finished goods and construction. The real GDP during 2004 increased by 4.4 percent. The nominal GDP was about $11.7 trillion. Housing starts were up by slightly more than 4 percent for the year. And the nation’s unemployment rate decreased to5.5 percent in 2004 from 6 percent in 2003. Interest rates continued to be low (prime rate was 5.25 percent at the end of 2004) but have risen gradually, following rising inflation.

Jan 1, 2005