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By Henning Schwarz, Ade Ogunsola, Anas Almousa

"The Riyadh Metro, commissioned by Arriyadh Development Authority “ADA” - the executive arm of The High Commission for the Development of Arriyadh -, forms part of a new public transport-system of Saudi Arabia’s fast growing capital city. The Design & Build project consists of 176 km of Metro Line with 57 km of tunnels. Beyond the Design and Construction, an additional aim of the ADA is to introduce up-to-date methodologies and improve safety in construction projects. A systematic dilapidation survey of buildings and infrastructures was a prerequisite for designing the required instrumentation and monitoring tools. Site investigations required of existing methodologies and the use of geophysical methods for achieving reliable results. Large diameter TBM tunneling is challenging in hot weather conditions and karstic ground. The present paper shows how modern technologies for underground construction are introduced into the local industry and gives an outlook on future projects in the Kingdom of Saudi Arabia. INTRODUCTION Riyadh, the capital city of the Kingdom of Saudi Arabia, is a fast growing city with more than 5.7 million inhabitants. The growth of the city is linked to the recent history of the Kingdom, where some initial milestones from the 1950’s can be highlighted: Revenue generation from the exportation of oil from the Kingdom; downstream investment of oil revenue in the reconstruction and development of the Kingdom; a general plan for the settlement of the Bedouins; the provision of a public electricity network for the city; the opening of the Riyadh - Dammam railway corridor providing a link from the capital to the Eastern Region; the commissioning of Riyadh airport (converted to Riyadh airbase, after the opening of King Khalid International Airport in 1983); and the relocation of ministries and other central government agencies in 1955. In 1974, The High Commission for the Development of Arriyadh was established as the organizational, planning, executive and coordinating body responsible for the development of Riyadh. Arriyadh Development Authority “ADA”, established in 1983 is the High Commission’s executive, technical and administrative arm. The ADA is responsible for implementing the High Commission's organizational, planning, executive and coordinating decisions and missions. The ADA’s president is a member of the High Commission (ADA 2015). One of the remits of the ADA is the preparation and execution of a transport plan for the city of Riyadh."

Jan 1, 2016

By Vincent T. Ricca

Acid mine drainage is a serious water pollution problem, for its contaminants will eventually effect the quality of the receiving streams. According to the Appalachian Regional Commission (1969)1, 10, 500 miles of streams have been polluted by mine drainage, and 70 percent of this acid pollution is accounted for by underground mines. Due to the severe damage to aquatic life, to recreational and industrial use, and to domestic water supply, more stringent mining and anti-pollution laws have been legislated and coal mine operators are required to treat the mine water discharges to meet the minimum standards. For years now, abatement and treatment methods have been extensively studied. Progress reports presented in the Fourth Symposium on Coal Mine Drainage Research, 1972 1 suggest that a thorough investigation and understanding of the basin discharge is necessary in order to cope with the mine drainage problem. The extent of mine water discharge contamination can be considered as a function of the basin streamflow and acid generation load.' A conservative treatment cost estimation these days is $0.40 per 1, 000 gallons for water with 100 ppm iron, 500 ppm acidity. These figures need not include collection and pumping costs nor the cost of dispersing of chemical waste by-products. To achieve optimal abatement and treatment of mine drainage, predictions of the quantity and quality of mine water discharges are needed. Basin discharge is a continuous process and it can be considered as a. macro-system. This system can be subdivided into micro-systems to describe the various mine discharge .types in the basin. The mining activities could produce acid water discharges from deep mines, stripmines, or associated gob piles. A total study entitled ?Resource Allocation to Optimize Mining Pollution Abatement Programs?* will consider all of these sources. However, this paper will discuss only one micro-system, the drift (deep) mine type. We will look at a single mine and its watershed. The total research project considers a multiple mining complex in an extensive stream basin.

Jan 1, 1973

By Jamal Rostami, Omid Frough, Wei Hu

Characterizing the abrasiveness of soil/rock and the allowable wear of hard-facing products in various conditions is a critical factor in selection of the best material for certain applications related to drilling and excavation in mining and construction industries. The Soil Abrasion Index test machine at Colorado School of Mines (CSM) is one of the recently developed unique systems capable of testing soil/crushed rock abrasion under various conditions, such as dry, wet, and saturated settings. It is also capable of testing the performance of various types of hard-facing materials in a given geo-material. This paper studies the wear properties of different hard-facing materials in various crushed rocks from a surface mining operation in the iron range region of the USA. The hard-facing materials include regular and hardened steels and six different specialized hard facings, based on chromium carbide. The soil/rock include a standard sand and two rock samples from the surface mine. Fourteen abrasion tests were conducted, where the weight loss of each hard-facing material was measured over timespans up to 1 h of testing. The results show the distinct performance differences between the steels with 17 HRC and 43 HRC hardness and the hard-facing products for this application. The results show the possibility to evaluate the abrasiveness of different rocks at a mine or construction site and the performance of various hard facings in similar working conditions. This is a practical solution for selection of the cutting tool or reinforcement of bucket lips and truck beds for comparison of relative wear life between different wear-resistant materials.

By Pascual Perazzo Vaschetti Gabriella

The increasing emphasis on environmental issues has crucial importance in mining projects, hence in tailings dams. Their water barrier needs a two-fold environmental assessment: the environmental impact caused by construction activities, and the environmental impact over time. Unfortunately, tailings dams’ failures have great and long-lasting environmental consequences, and as mining sites become bigger and tailings dams higher, the risk of failures may increase. Furthermore, since these dams are mostly constructed over many years, design parameters/materials may change, the engineers may change, and since cost is a driving parameter, less attention may be given to quality control and monitoring. Geomembrane water barriers mitigate such impacts.

Sep 30, 2022

The 1965 Lignite Symposium, the fourth in a series and the third sponsored by the University of North Dakota and the Bureau of Mines, was held at Bismarck, N. Dak., on April 29-30, 1963. Them 7 symposia provide a forum for those interested in the technology and utilization of solid fuels, especially lignitic coals. As part of the meeting, a 200-mile field trip was taken including inspection of (1) the 200-megawatt, pulverized Lignite-fired Leland Olds plant of Basin Electric Power Cooperative, under construction near Stanton, N. Dak.; (2) the site of the Glenharold mine of the. Truax-Traer Goal Co., Division of Consolidation Coal Co., where a wheel excavator was being assembled; (3) the operating Beulah mine of Knife River Coal Mining Co., subsidiary of Montana-Dakota Utilities Co., near Beulah, N. Dak.; and (4) the 400-megawatt, hydro-electric Garrison Dam powerplant, near Garrison, N. Dak.

Jan 1, 1966

By G. Blackwell

In the 1980's the Canadian surface mining industry was confronted by declining competitiveness in the face of low cost foreign producers and alternative materials. Low metal prices undermined profits for many mining companies. Restructuring, rationalization, capacity reduction, technology transfer, as well as favourable currency rates and higher commodity prices, helped revitalize the industry by the close of the decade. Now in the 1990's, however, the need to improve competitiveness for profitability has re-emerged in greater intensity. In the current climate it is considered that there are three strategies available to industry to ensure profitability: continued rationalization and restructuring; optimization of operating practice; and technology development and transfer.

Jan 1, 1993

By Manis Kumar Jha, D. D. Pathak, Archana Kumari

Treatment of secondary/waste to recover rare earth metals (REMs) is gaining importance due to its increasing global demand, lack of availability of high grade natural resources and huge generation of secondaries. Present paper reports the critical review on available processes for recovery of REMs from secondaries viz. manufacturing scraps, e-waste, industrial residues such as red mud, fly ash, waste water, etc. Hydrometallurgical processes with combination of Beneficiation/ Pyro-/Electro techniques are discussed to recover REMs effectively. The recommended processes require less energy to deliver high purity yield which is one step towards green environment. Salient findings on various methods are reported with recommendations which will be helpful to researchers working in the area of REMs extraction.

Mar 1, 2018

By E. Kumar, L. A. Kumar

"A methodology is proposed to develop an optimization model to understand the impact of transporting minerals, from mines to the final destination, on air quality. Recently, there has been increasing concern about the combined effects of multiple activities over many years, and the regional environmental changes brought about by a single project. Environmental issues in the iron ore industry have highlighted the need to broaden the cumulative impact assessment. In this study, we simulated the optimal routes and quantity of materials needed to meet the destination plant demand based upon environment constraints (level of air pollution), as well as the cost of transportation and availability of materials. Multiple scenarios were developed to analyse the effects of changes in routes, alternative transport system (or multi-modal split), traffic congestion, and the cumulative impacts on air quality. The air quality impact zones of the study area were demarcated using a GIS technique. The expected outcome of the study is the selection of a suitable transport system for a particular site with the least impact on air quality, including the transportation route, relative to the minimum cost of transportation of the minerals from the mines to their final destination. The proposed methodology is evaluated with a case study. IntroductionIn India, the process of environmental impact assessment (EIA) has been focused primarily on the local impacts of projects, without considering regional environmental effects. Environmental clearances for proposed projects are based on reports of local impacts. However, any developmental project poses a potential risk to the environment as a whole, and not just in the immediate vicinity of the project. Recently, there has been increased concern about the combined effects of multiple activities over many years—the regional environmental changes due to development of a single project (Dutta, Mahatha, and De, 2004). Environmental issues throughout the country, particularly in the iron ore industry, have emphasized the need to broaden the analysis to include the combined impacts, or those forecast for a proposed region, on an existing environment. The most significant adverse environmental consequences of iron ore transportation are the deterioration of biodiversity and air quality (Kumar and Ajay, 2015)."

Jan 1, 2017

By S. Serranti

The recycling of end-of-life concrete into new concrete is one of the most interesting options for reducing worldwide natural resources use and emissions associated with the building materials sector. The possibility to realize a larger re-use of silica aggregates from old concrete, strongly contributes to reduce environmental impact (reduced exploitation of natural resources, reduction of CO2 emissions, airborne dust production, etc.).To reach this goal, innovative processing techniques, as well as innovative sensing units and architectures have to be developed. In this perspective an analytical approach, based on hyperspectral sensing techniques, is proposed, discussed and critically evaluated in order to perform an automatic quality control assessment, finalized to maintain a high standard of concrete demolition waste, from the earliest stage of recycling to the further processing stages, according to the detected in-situ demolition waste characteristics. The paper deals with the analysis and the evaluation of the problems related to the integration of this approach with state-of-the-art demolition and building processes and procedures. Keywords: end-of-life concrete, recycling, hyperspectral imaging, NIR spectroscopy, quality control

Sep 1, 2012

By Roger G. Long

In May 1973, the Bureau of Mines asked Arthur D. Little, Inc. (A DL) to investigate existing industrial communication standards that may be applicable to the problem of developing standards for mine communication, considering that the standards that may ultimately be developed will require simple field procedures for the industry and the inspectorate to determine that communication systems are properly functioning. The emphasis on this study is on telephone communications as related to coal mine applications. B. TASKS The tasks agreed upon for this program were as follows: 1. "Investigate the current practices and existing standards of other industries under government regulation. 2. Determine applicable methods for industry personnel and inspectors to ascertain conformance on-site with minimal test hardware. 3. Review the Bureau's approval, testing and inspection procedure as it may impact the development of such standards. 4. From the above studies investigate the development of installation and performance standards for mine communications, including voice and telemetry. 5. Prepare a written report specifying what standards and field inspection techniques are applicable with recommendations for development of subsequent data and ultimately standards and field inspection techniques. 6. Prepare a written summary of the findings of various investigations with an appendix covering the detailed findings of each investigation. 7. Prepare a list of suggestions of additional assistance the Bureau might require in subsequent phases of developing communication standards and means of ascertaining performance."

Jan 1, 1973

By V. Estrada, G. Aguilera

"Since the most of mineral processing are wet, and for more specific applications where it is necessary to increase the purity through leaching and / or concentration, the proper dispersion is the first, and perhaps more crucial stage in the whole chain of processing. This specific process is based on the formation of a dispersion or suspension of mineral, trying to make the mixture as homogeneous as possible, and with specific rheological conditions. Sometimes it is not enough agitation to make it happen, so that chemical additives are used as an aid. However, the addition of chemicals strongly alters the viscosity and other rheological properties of the suspension factor to consider for subsequent steps to ore beneficiation. In other hand, in a process where no chemicals used often employ large quantities of water to achieve dispersion. But if an efficient chemical agent, which optimizes said dispersion through a specific physicochemical effect on the particle surface is used, also it can generate rheological advantages, besides achieving rational use of water and increase the recoveries of the product main about also optimal costs. The aim of this work is to find the optimal rheological conditions for a dispersion of kaolin as study case, looking for stability, best disaggregation, viscosity and pseudoplasticity.To find the optimal additive, the evaluation parameters were: 1) Best degree of dispersion of the suspensions according to the analysis of the flow curve; 2) Best level of disaggregation of particle chemical analysis delaminated by Particle Size Distribution; and 3) Best thixotropic rheological parameters and pseudoplasticity. Finally the optimum additive as one that meets the best combination of parameters is proposed.INTRODUCTIONKaolin is a clay material formed by altering of feldspar composed mainly for kaolinite. Depending on the application, the kaolin as raw material must be refined and processed because the ores of clays contain usually a lot of impurities derived of its sedimentary source, such as feldspar, mica and quartz (Torres, et. al., 2011). According to the experience on the plant floor and the publication of several scientific papers, it is known that the dispersion is a crucial stage in mineral processing (Greene, Duke, & Hunter, 1965) (Raghavan, et. al., 2004), not only because of the disaggregation of particles, besides because of the humectation of them. Is clear that disaggregation of particles give to the suspensions rheological stability, and the humectation improves the effect of further processes like grinding or chemical treatment. The dispersion process involves making a suspension of the mineral with a solvent which is usually water, to obtain a homogeneous dispersion, with the aid of energy of stirring. Sometimes is not enough the agitation (even with high energy) for this to occur, so is necessary the use of dispersing substances which introduce ions and molecules as modifiers of chemical potential, forcing the molecules of the material to disperse. Sometimes their use even could affect the pH of the suspension in a non-desirable condition. (Flores, 2013)."

Jan 1, 2016

By J. L. Broadhurst, S. Rumjeet, S. T. L Harrison, T. Chimbganda

Post-mining land use for the production of industrial crops has the potential to mitigate environmental and socio-economic impacts of mine closure and stimulate post-mining economic growth. Fibre-rich plants are of particular interest due to their multi-product potential. In the South African context, where there are many abandoned and end-of-life mines near human settlements, an opportunity presents to assess the feasibility of transforming post-mining land into productive land and building resilient communities through the development of multi-product value chains from fibre-rich plants such as kenaf, hemp or bamboo. This paper provides an overview of the plant selection criteria, phytoremediation potential and the downstream options for the recovery of products and value from bast fibre plants (hemp and kenaf) and bamboo. Based on findings from a comprehensive review of the published literature, as well as interviews with relevant experts within South Africa, it appears that bast fibre plants are the best downstream option for producing ‘green’ textiles and high-end niche products, whereas bamboo is more suitable as a replacement for conventional timber. Although fibre plants have the potential to extract metals from soils, high concentrations may inhibit plant growth and affect the quality of the final fibre product. Further site-specific studies would thus be required to select the best route for both land remediation and optimal product recovery. Keywords: Bioremediation, bamboo, kenaf, hemp, multi-product value chains, sustainable postmining land use

Jan 1, 2020

By S. J. Schatzel, V. Gangrade

A ventilation research study was conducted by the National Institute for Occupational Safety and Health and a cooperating trona mine in the Green River basin of Wyoming, USA. The mine operation uses the longwall mining method in trona bed 17, a commonly mined unit in the region. The longwall face length is 228 m (750 ft), and caving on the face occurred up to the back of the longwall shields. The mine is ventilated using a main blowing fan and a bleeder shaft. For this study, sulfur hexafluoride (SF6) tracer gas was released in two separate monitoring experiments. For the first experiment, tracer gas was released on the face, this test focused on airflow along the longwall face of the active panel. Face test showed the airflow patterns to be more complex than just head-to-tail flow in the main ventilation air stream on the active panel. For the second experiment, tracer gas was released 2 crosscuts inby the face on the headgate side, this test focused on gas transport in the mined-out portion of the same active panel. Gob test showed a pathway of movement through the front of the active panel gob that moved outby from the tailgate corner. The primary pathway of tracer gas movement in the active panel gob was towards the headgate and tailgate bleeders and out of a bleeder shaft. The rate of movement towards the back of the gob was measured to be 0.19 m/s (37 fpm).

By Sebastian Avalos, Julian M. Ortiz, Willy Kracht

Semi-autogenous grinding mills play a critical role in the processing stage of many mining operations. They are also one of the most intensive energy consumers of the entire process. Current forecasting techniques of energy consumption base their inferences on feeding ore mineralogical features, SAG dimensions, and operational variables. Experts recognize their capabilities to provide adequate guidelines but also their lack of accuracy when real-time forecasting is desired. As an alternative, we propose the use of real-time operational variables (feed tonnage, bearing pressure, and spindle speed) to forecast the upcoming energy consumption via machine learning and deep learning techniques. Several predictive methods were studied: polynomial regression, k-nearest neighbor, support vector machine, multilayer perceptron, long short-term memory, and gated recurrent units. A step-by-step workflow on how to deal with real datasets, and how to find optimum models and final model selection is presented. In particular, recurrent neural networks achieved the best forecasting metrics in the energy consumption prediction task. The workflow has the potential of being extended to any other temporal and multivariate mineral processing datasets.

Jun 16, 2020

EIA is a test of a development proposalÆs legitimacy and asks two questions: not only æis the proposal competent?Æ but also ædoes the proposal have moral authority?Æ For reasons of miningÆs historic importance and of a scientific and technological industry culture, traditional EIA has focussed on the first on these, an increasingly misplaced priority in a changing world.This paper explains why competence alone is not enough and examines the second of the two questions: what is meant by a projectÆs moral authority, why does it matter, why has it taken so long to become an issue and what, in practical terms, can project proponents do about it.

Jan 1, 2004

By Anand Kumar Agrawal, Kinzel Klaus Peter, Lorenzo Micheletti, Cristiano Castagnola, Horst Kappes, Andre Oliveira, Björn Rösner, Philippe Bermes

Blast furnaces are widely employed today for iron production all around the world, with a total production of around 1.2 billion tons per year. Its operating principle, which relies on usage of coke to reduce the ore, to ensure the permeability in the reaction vessel, to maintain its flexibility of operation and acceptability for varying qualities of iron ores. The blast furnace route is widely considered as the most economic and efficient route of iron production, however it is based on fossil energy carriers. The blast furnace route has undergone significant developments in terms of energy efficiency in the last decades, which led to a substantial reduction in the use of fossil reduction materials. Being an energy intensive process, competitiveness and cost saving in the blast furnace plant was always strongly related to the saving of energy and hence reduction of CO2 emissions. In addition to this, EU emissions trading system (EU ETS) as a cornerstone of the EU's policy in response to climate change has set new “challenges” for iron production in Europe. Paul Wurth has always been deeply involved in the development of energy saving technologies for blast furnaces. In the following a review of energy saving achievements developed in the last decades will be presented and the potential of available CO2 saving technologies will be summarized. Additionally, an outlook about the potential of future technologies, concepts and their impact on the blast furnace and the steel plant’s energy balance will be discussed. Finally, the replacement of carbon by hydrogen as reduction agent in the steel plant will be reviewed, with special focus on a comparison of costs and incentives.

Oct 1, 2019

By Dennis J. Callaghan

This report is the result of information obtained from a review of related literature, personal inquiry and on-site examination of active surface coal mining operations. Four improved surface coal mine systems are described in detail and evaluated for feasibility, implementation requirements, environmental benefit and costs. Engineering feasibility emphasizes equipment availability, compliance to design requirements, practicality and industry rating. Implementation potential emphasizes immediacy, ease, acceptability and constraints. Special attention was given to environmental responsiveness, both with regard to the solutions to mined-land reclamation problems and to the concurrency of reclamation. Each system description includes a hypothetical model mine with a depreciation schedule, capital summary, estimated annual production costs, sales price computation, production and operating cost summary, and a sensitivity analysis of mine price to stripping ratio. A program plan and time schedule for demonstrating a selected mining system covers site selection criteria, mine data collection, criteria for controlling and budgeting costs and reporting findings. Ten additional mining methods and techniques are briefly described and evaluated. Common reclamation problems are listed and described. Sixteen state reclamation laws and regulations are abstracted. Sixty-nine references are listed in the bibliography.

Jan 1, 1976

By J. W. Allen

This report reviews the work performed on Task M of Bu-Mines Contract H0220073 to develop an engineering model of a surface and subsurface communications system for normal mine operations and for post disaster rescue operations. The system concept provides for one-way transmission of digital information between a number of identifiable subsurface terminals or subcenters and a single surface station. It also provides 2-way voice communications between the subcenters and the surface station. The basic communications link is electromagnetic signaling through-the-earth, but the system is also capable of using mine phone lines as an alternate link. Engineering models of three subcenters and one surface terminal (see Figure 1-1) have been fabricated in order to demonstrate the system's performance. The system concept, however, permits up to 20 subcenters to be incorporated if desired. Additional subcenters are also feasible for large mines if they can be deployed in the mine to operate on a noninterfering basis.

Jan 1, 1973

By Paul G. Dunn

The planning of underground mines is a complicated process involving geological, engineering and operational constraints. MIRARCO is in the process of developing a 5D Mining Exploratorium where 3D mining models are combined with time (4th dimension) and costs (5th dimension). The mining exploratorium is a collection of external and inhouse software packages specifically geared to help underground mining companies arrive at better mine plans. This paper discusses the progress made in the development of the 5D Mining Exploratorium and a change in mine planning philosophy by conducting frequent audits in a Virtual Reality Laboratory. The development of genetic algorithms for optimising stope sequences is also presented.

May 1, 2003

By Weiran Zuo, Narayan Krishnan, Frédéric von der Weid, Emmy Manlapig, Fengnian Shi, Klaas van der Wielen

Laboratory study has identified a new application of high voltage electrical pulse technology for pre-weakening ores. In recent years, the Julius Kruttschnitt Mineral Research Centre (JKMRC), Newcrest Mining and SELFRAG AG have conducted joint research in validation of pre-weakening of SAG mill feed through the pilot scale tests and comminution circuit simulations. Ten tons of SAG mill feed with a top particle size 150 mm were tested with two pilot scale SELFRAG machines installed in Switzerland. A simulation study using JKSimMet software was carried out to find where the high voltage pulses pre-weakening technique can be best applied in a gold-copper ore comminution circuit, based on the data of the pilot scale SELFRAG tests. A novel comminution circuit was designed, which incorporated SELFRAG to pre-condition part of SAG mill feed (9.5 to 150 mm) and to treat the circulating SAG mill pebbles. The high voltage pulse technology effectively reduced the amount of ‘critical size’ particles in the SAG mill and pre-weakened particle strength for grinding. Attributing to the nature of bi-modal size distribution and the significantly reduced F80, the simulations showed that the SAG mill had spare capacity to process part of hydrocyclone underflow from the secondary ball mill grinding circuit. The simulations indicated that the novel comminution circuit had the potential to remove two MP1000 pebble crushers and one 10 MW ball mill from the existing 2000 t/h grinding circuit. A 5 kWh/t energy reduction by adopting the novel comminution circuit in a gold-copper operation may be realized. This would result in substantial savings in operation costs.

Jan 1, 2014