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By Mark A. Krall

The Conda Partnership's Dry Valley Phosphate mine is a thinly bedded, multiple seam, open pit mining operation where selective mining techniques are used to recover phosphatic shales. The mining methods used are truck/shovel and scraper/ dozer operations. The ore that is mined is shipped 32 km (20 miles) by rail to a beneficiation facility which upgrades the ore via washing and calcining. The mine and beneficiation complexes are owned by the Conda Partnership. The Conda Partnership is a joint venture between Beker Industries Corp. of Greenwich, Connecticut, and Western Co-Operative Fertilizers (U.S.) Inc. of Alberta, Canada. The Conda Partnership operates as a separate entity from the two partners.

Jan 1, 1984

By William Gleason

"In 2008, the world quietly hit a milestone that did not receive much fanfare or publicity, but it hit one that marked a turning point in the history of mankind and the way the planet is and will be inhabited in the future. It was in 2008 that, for the first time, more than half of the world’s population, an estimated 3.3 billion people, resided in urban areas. The world’s population had moved from being a majority of agricultural and rural society to an urban society. Andrew Whalley, deputy chairman for Grimshaw Architects, said this change in where and how people live will continue to increase urban populations and, by 2050, it is estimated that more than 6.4 billion people will live in urban areas. To meet these needs, Whalley, speaking during the keynote session of the 2105 Cutting Edge conference in Denver, CO, said future cities will have to be reimagined and redesigned to be more efficient. A large part of that design will be in the infrastructure of those cities.At the Fourth Annual Cutting Edge Conference, Sept. 21-23, much of the discussion was around how the tunneling and underground construction industries improve cities in a number of ways, including societal, environmental and in overall efficiency. There was talk, not just about the improvements that society enjoys at the completion of such projects, but also about the challenges faced by the owner and contractor in the construction of such projects.The conference, titled Urban Tunneling, brought together some of the top minds in the industry to not only discuss the issues faced today, but also those that will shape the industry in the future.For his part, Whalley spoke about a number of projects around the world and how they have impacted society in ways beyond simply providing a better means for transportation of people or water. Notably, he spoke about the Crossrails project in London.London is a city of 8.6 million people and a history that dates back nearly 2,000 years. It is a great example of the challenges the industry faces in bringing modern efficiencies to an established city.Running more than 100 km (62 miles) with more than 42 km (26 miles) of tunnels passing through 40 stations, including 10 new stations, the project is the largest in Europe and will transform the way people move about the city."

Jan 1, 2015

By J. J. Kellar

The near-infrared (NIR) (12,000-4,000 cm-1) region of the electromagnetic spectrum, between the mid-infrared and visible, has often been viewed by spectroscopists to be of limited utility. This is unfortunate, and recently the use of the NIR has increased greatly, primarily for the quantitative analysis of food and agricultural products. However, many other areas of application of NIR spectroscopy remain unexamined. In this paper a novel use of NIR in the area of flotation chemistry is demonstrated. Specifically, it is shown that NIR/Internal Reflection Spectroscopy (IRS) can be used to quantify collector adsorption reactions in-situ.

Jan 1, 1990

By Robert Stefanko

Longwall mining appears very attractive from an engineering standpoint because of its simplicity. The use of one long, continuous face can simplify power distribution, ventilation, and supervision, and minimizes or prevents lost time associated with the tramming of equipment in room-and-pillar systems. Since the longwall system is more amenable to automation, it is inherently safer than room and pillar. Remote control of all face equipment from gate roads will obviate the exposure of men in the face area. Considering what has been said, it seems a paradox that more longwall installations are not found in the United States. However, with favorable mining conditions in relatively level seams of adequate height under shallow cover, it has been possible to develop highly productive, mechanized, room-and-pillar systems. Thus there has been no real incentive to employ longwall in the United States. In Europe, mining companies usually have very little choice between the two systems. Pitching seams of low height located at great depth dictate the use of longwall methods. With depletion of its readily accessible reserves, mining conditions will be similar to those now prevailing in Europe, and an increase in the use of longwall in the United States can be anticipated.

Jan 1, 1963

By A. T. Iannacchione

Unrecognized roof beam failures resulted in 69% of the falls of ground injuries occurring in underground U.S. stone mines from 1990 to 1996. Field investigations at 45 underground stone mines suggest that excessive beam sag or deflection is the principal unstable roof behavior characteristics associated with miner injuries. Laminated roof structures, common in most underground stone mines, allow the immediate roof to separate into distinct beams. The timely determination of roof beam deflection could provide stone miners with advanced knowledge of potentially hazardous roof. Existing methods to assess roof conditions consist of observational and monitoring techniques. Observational techniques include open drillholes, sounding, wedging, and borescopes. Monitoring techniques include scratch tools, extensometers, telltales, Miners Helpers, and Guardian Angels. 1 Miners have difficulty utilizing these techniques because roof beams are located an average of 8 m (26.5 ft) above the miner's head in environments that are dark, dusty and noisy and these deflections are measured in millimeters of movement. To help mitigate the potential for falls of ground injuries to underground stone miners, the National Institute for Occupational Safety and Health (NIOSH) has developed the Roof Monitoring Safety System (RMSS) to aid in monitoring dangerous levels of roof beam deflection. If enough site-specific information is collected and placed on highly visible maps, individual mining operations could establish general guidelines for responding to specific roof beam deflection occurrences. This would help in implementing a pro-active, comprehensive roof control plan for reducing falls of ground injuries.

Jan 1, 1999

By Stephen Semeniuk

Working with junior mining companies as a valuer, my experience with regulators is that simplicity works and the sales comparison method is the way to go. What I like about Mr. Ellis?s approach (as in his Table 7) is the integration of commodity prices with the timing of acquisitions and the implication of price changes in gold on the adjustment of individual project valuations. However, the sample gold-related appraisals in Ellis?s paper are pre-2008 transactions and readers should be made aware of the current market for such projects. Before moving on, to be noted is that the effective date of the Las Brisas appraisal (Ellis?s sample Appraisal 3) is Feb. 10, 2006; given that the subject value of Transaction 9, Choco 10 in Ellis?s Table 6 was listed as $353 million for a 95% interest in the con-cession, I am uncomfortable accepting that the acquisition was suddenly worth the adjusted value of $1,205 million (as given in Ellis?s Table 7). In some cases, illiquidity discounts can apply, and commodity-wise, in the one-month period between the acquisition in January 2006 and the adjustment to the Las Brisas conditions as of February 10, 2006, the indicated gold price change was only 41 cents/g ($12.60/oz); i.e., from $17.50/g to $17.91/g ($544.40/oz to $557/oz).

Jan 1, 2012

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Li-rich red mud was leached using acetic acid to investigate the leaching behavior of lithium followed by neutralizing with hydrochloric or oxalic acid. By neutralizing red mud using diluted hydrochloric acid (0.01 mol/L), 58.04–60.27% of lithium was leached using 25% acetic acid at 95 °C for 60 min. In the meantime, more than 95% of sodium and 85% of calcium were also dissolved in the leachate solution. While oxalic acid (0.5 mol/L) was used to neutralize red mud prior to acetic acid leaching, lithium performed lower leaching efficiencies (42.41–46.88%) in comparison of using of hydrochloric acid–neutralized red mud. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the condition. In this study, 25% (v/v) of acetic acid, at 85 °C for 60 min, was demonstrated as optimum conditions for lithium extraction from oxalic acid–neutralized red mud using acetic acid. The results would be useful and of interest for lithium recovery and purification from red mud.

By Paul C. Miclea

In case of a major fire in a tunnel between stations or ventilation shafts, if the buoyancy effect of the hot gasses is stronger than the airflow induced by the fans, the risk of backlayering could restrict the safe evacuation of people. Obstructions in the tunnel and alternate airflow paths can further reduce the air velocities past the fire. Currently there are two computer programs available to address the issue of underground fires: o "Subway Environment Simulation" (SES), Version 3.0, developed by Associated Engineers, a Joint Venture of Parsons Brinckerhoff Quade & Douglas, Inc., De Leuw Cather & Co., and Kaiser Engineers, Inc. for the U.S. Department of Transportation o "MFIRE", Version 1.26, developed at Michigan Technological University for the U.S. Department of the Interior, Bureau of Mines. As implied by its name, the SES program was developed specifically for the analysis of subway ventilation systems. It can be used to analyze the heat released into, and removed from, a subway or vehicular tunnel and to determine the effect of ventilation elements on airflows throughout the network of stations or other merging tunnels. It has a special feature allowing the user to predict the effects of a fire at any location within the subway system. Version 3.0 of the SES program is designed to be used with a "critical velocity" calculation in order to determine whether or not tunnel airflows can be controlled during a train fire emergency. The original version of the program was written in FORTRAN for mainframe computers, such as the IBM 4381. Recently ICF Kaiser Engineers has compiled a version of the SES program for PC use. The MFIRE program simulates the interdependence between a mine ventilation system, with its pertinent fans and structures, and changes in ambient conditions or a source of heat, such as a fire. It also accounts for natural ventilation. The program is written in FORTRAN 77 and compiled for 8086/8088 based microprocessors, allowing it to be run on an IBM PC or compatible computer with a 2.0 or a later version of DOS, 256K random access memory (RAM), and a text editor. This paper reports the comparative results of an application of both programs for the same network in a recent study.

Jan 1, 1991

By Michael M. Kimberley

Gold is sufficiently valuable that concentrations as small as 1 p.p.m. may support low-cost mining. Mindful of this, Sunoco Energy Development Company (Sunedco) obtained fire-assay analyses on some sulfide-rich sandstone encountered during routine drilling. Initial fire-assay values from independent laboratories indicated some significant gold values and independent analysis by atomic-absorption spectroscopy also indicated detectable gold at economically interesting concentrations. Sunoco geologists realized the potential for spurious results inherent in both fire assaying and atomic-absorption spectroscopy. Fire assaying that relies on gold measurement by weight requires perfect separation of gold from all other elements, Imperfect separation may artificially enhance apparent gold concentrations. Atomic-absorption-spectroscopy (AAS) measurements are potentially subject to interferences from other elements. For example, Beamish and Van Loon (1977, p.4) report AAS measurements of 4 p.p.m. Au to be characteristic of completely barren soil samples when samples are prepared by standard dissolution in HC1 to form solutions of about 10,000 p.p.m. total cations (mostly Na, Ca, Mg, Al, and Fe) .

Jan 1, 1981

By Roger Storry, Donald Bruce, Arnaud Hochart

"INTRODUCTIONThe Port of Miami Tunnel (POMT), designed and constructed by Bouygues Civil Works Florida between 2009 and 2014, was a Public Private Partnership between the Miami Access Tunnel Concessionaire, Florida Department of Transport, Miami-Dade County and the City of Miami. The project comprises dual 11.3m internal diameter, 1.27km long, twin lane road tunnels running between Watson and Dodge islands and under the main shipping channel in Biscayne Bay (Figure 1).The POMT was a unique project which embodied many technical firsts and involved the first large diameter tunnels constructed through Florida’s challenging sedimentary carbonate strata. At the outset, a comprehensive ground investigation was performed, using both conventional and less conventional investigation techniques, to characterise the highly heterogeneous ground conditions.The findings of the investigation had a major impact on the tunnelling methods, triggering a series of mitigation works to ensure that the tunnels could be excavated safely and effectively. The mitigations included modifications to the already designed Tunnel Boring Machine (TBM), to facilitate an innovative excavation process, and a unique grouting campaign (Storry et. al. 2013a). The project was completed and opened to traffic in August, 2014 and has significantly alleviated traffic congestion in Downtown Miami.GEOLOGICAL CONTEXTThe geological conditions at the project site consist of carbonate sediments which can be divided into distinct geologic units; the Miami Limestone Formation (Layers S3, S4), the Fort Thompson Formation (Layer S5), the Anastasia Formation (Layer S6), the Key Largo Formation (Layer S7) and the Tamiami Formation (Layer S8). Multiple changes in sea level over a relatively short geologic time scale have resulted in a heterogeneous profile consisting of interbedded sedimentary rocks and sediments, which vary widely, both vertically and laterally (Figure 2)."

Jan 1, 2016

The objective of this international conference was to assist the mining and minerals industries in their global transition to sustainable development. The main theme of the meeting, therefore, was the development, monitoring and assessment of sustainable development criteria for mineral operations. Emerging technologies that can assist in the development of criteria and performance measurements were also presented at the meeting. A goal of the conference was also to conclude with a consensus plan and a process, representing a variety of stakeholders, which can provide guidance to the global minerals community on the path to sustainable development. A number of papers were not submitted in time to be included in the printed proceedings. Hence this addendum was compiled and includes last minute paper submissions. The pages of this addendum are numbered consecutively to the main volume of proceedings, so that when a reference is made to a paper, a proper page number may be quoted.

Jan 1, 2003

By C. P. Boddy

One of the most difficult tasks a project manager will have in pre-mine planning is dealing with the mine site's hydrologic regime. Numerous federal statutes passed by Congress in the last decade have made the coal mining industry more responsive to the environmental impact during all phases of the mining process. Permitting these mines has dictated a cradle to grave approach in dealing with water related issues. This paper will attempt to explore the application of these technology- based laws and their direct application to the unique environment found in Alaska's interior regions.

Jan 1, 1985

By Michael Gobla

"Since 1994 the Bureau of Reclamation (BOR) has used risk analysis to evaluate dams. Risk considers both the likelihood of failure and the expected consequences should failure occur. Risk analysis relies on the detailed formulation and critical analysis of all possible potential failure modes. Potential failure modes are formulated by describing the sequence of events that must occur to result in failure, where failure is defined as the uncontrolled release of the impounded reservoir. Failure occurs in response to loadings such as water seepage through a dam (static forces), shaking from an earthquake (dynamic forces), sudden flood inflows (hydrologic forces), or accidental overfilling (operational errors). Reclamation has, to a limited extent, applied risk analysis to inactive and abandoned mines to evaluate tailings dams, pit lakes and flooded underground mines. Case histories of potential failure mode analysis, as applied to mine impounded water, illustrate what critical technical information is needed to determine if failure is likely, what the consequences of failure are likely to be, and what are the highest risks that should be addressed first.IntroductionImpounded water and high water content wastes at mining and industrial processing sites are potential threats to public safety and the environment. Recent failures such as the TVA Kingston flyash impoundment failure in Tennessee in 2008 (4.1 million m3 or 5.4 million cu yd) release, the Mt. Poly Tailings Dam failure in British Columbia in 2014 (4.4 million m3 or 5.8 million cu yd) release, and the Samarco Fundao Tailings Dam failure in Brazil in 2015 (59 millon m3 or 78 million cu yd) release have renewed attention to this issue. Potential risks from impounded water at mining and industrial sites originate not only from tailing dams, but also from water in process ponds and conveyance pipelines, sediment retention dams, water retention dams, mine pit lakes and flooded underground mine workings.Conventional water retaining dams also have a record of failure. Notable examples of failure include Vajont Dam in Italy in 1963 (2,600 lives lost), Banqiao and Shimantan Dams in China in 1975 (171,000 lives lost), and Machhu-II Dam in India (10,000 lives lost). After the 1976 Teton Dam failure in Idaho, the U.S. Bureau of Reclamation (BOR) established a Dam Safety Program. By 1984, the agency developed and began using risk analysis methods. BOR operates and maintains an inventory of hundreds of aging dams which were designed and constructed over a period of 100 years. Many of these facilities were designed and constructed prior to the development and adaptation of modern soil mechanics in dam engineering. Diligent observational monitoring, detailed site investigations and the application of risk evaluation to the BOR dam inventory has identified many deficiencies resulting in significant demands on available funding for remediation efforts. The application of risk analysis has allowed the agency to rank sites by risk. By giving priority of remedial efforts to high-risk sites, significant improvements to dam safety have been achieved."

Dec 1, 2016

By I. Weir-Jones

I. Introduction The experimental work described in this paper was carried out during 1967 and 1968 in an inclined reinforced concrete adit which had been driven during 1965 and 1966 to provide primary access for a new gypsum mine. The new mine was situated near the village of Sherburn-in-Elmet in central Yorkshire in an area of extensive post-glacial plains of deltaic and lacustrine origin. These plains cover a large area of this part of Yorkshire extending inland from the coast for a distance of about 35 miles. The gypsum deposit at Sherburn dates from Permian times and it is considered" to have been associated with the western-most edges of the ancient Zechstein Sea which was also responsible for the formation of the extensive evaporite deposits in north-east Yorkshire. The gypsum deposit, which varies in thickness from 10 to 15 feet, is extremely pure and it occurs quite close to the surface; in the Sherburn area the overburden is only 120 feet thick. The proximity of the deposit to the surface, however, tends to give a somewhat false idea of the magnitude of the problems associated with its extraction. These problems were all related to the nature of the overlying strata. As has already been mentioned, the surface deposits are post-glacial and they consist of an extremely large number of thin layers of varved clays, fine silts and sands extending down to a depth of 75 feet. From the bottom of the post-glacial deposits to the seam, a distance of about 45 feet, the strata consists of a succession of marls, weak sandstones, and siltstones, which although they are inherently incompetent materials, are appreciably stronger

Jan 1, 1971

By Z. Hajnal

Three years ago a research program was initiated at the University of Saskatchewan to develop seismic surveying techniques for use in the Precambrian geological environment. The success of the reflection method in many younger geological settings suggested that this is the technique which would be the most suitable for experimentation. A successful adaptation of this technique to the Shield environment would make mapping of rock formations possible to much greater depth than is possible at the present time with any other applied geophysical technique. This presentation attempts to illustrate the advances which have been made in this program and will provide some insight into future plans. The field investigations were limited to the Flin Flon basin near to the town of Flin Flon, Manitoba (Fig. 1). This area was chosen because the surface geology has been mapped in great detail and it is a very important base metal producing region. It is an ancient sedimentary basin with some characteristics similar to areas where the reflection method has been successful.

Jan 1, 1976

By R. L. Loofbourow

The Sunro Copper Mine is near the south coast of Vancouver Island about 35 miles west of Victoria. Failure of the roof of a large open stope let a good sized mountain stream into the mine. Broken are, boulders and sand were washed into the underground mill and out through a 7 800-foot adit. The adit became plugged; water burst out an a ridge above the adit, washing out the portal and o trestle by which it was reached, Rock and ore are strong but several systems of steep, pronounced but generally tight fractures are found on and parallel to the walls of the orebody. The stope was started from a slusher drift 390 feet below the bed of the River and brought up to an elevation 155 feet below the River by blasting vertical and horizontal rings of longholes in the nearly vertical orebody. Mining was stopped there and five months were given to grouting and bolting the pillar under the bed of the River, During this time and for several months thereafter sloughing increased the width, length and height of the stope. At the last known observation the stope was 77 to 96 feet wide, 185 feet long and the highest point of the domed back was only 55 feet below the River. The flooding took no lives. In other respects, however, it might be difficult to find in mining lore o more savage example of the application of "Murphy's Laws".

Jan 1, 1968

By R. V. Stewart

This chrysotile asbestos orebody is located near the northern tip of the Province of Quebec, Canada. It is some 1818 km (1130 mi) north of Montreal; 480 km (300 mi) north of the tree line and is situated within the zone of continuous permafrost. The open pit ore zone is approximately 0.4 km (1/4 mi) in length some 61 m (200 ft) in width and plunges at 25-30 below surface to a vertical depth of at least 610 m (2000 ft). The orebody was originally evaluated by programs of surface mapping, diamond drilling and bulk sampling. The fibre is semi-crude, possesses excellent strength, and good fibre length distribution.

Jan 1, 1978

By Gleason

"From June 16 to 19, more than 1,400 tunneling and underground construction professionals gathered in Chicago, IL for the bienial Rapid Excavation and Tunneling Conference (RETC). There, they were greeted by a full technical program and an exciting exhibit hall that provided a comprehensive look at the world’s bustling tunneling and underground construction industry.The successful conference was a reflection of the industry itself, which is to say, busy. As much of the world has begun to focus on creating a cleaner and greener environment, the global tunneling industry has seen an uptick in infrastructure projects move from design-build to construction phase. With a global shift away from the use of fossil fuels, major cities around the world are looking to increase public transportation options, which leads to the need for more transportation tunnels. And as urban populations continue to grow, the need for clean water calls for more tunnels, and as urban footprints continue to expand, the need to increase and update combined sewage overflow tunnel grows with them.During two and a half days, more than 20 sessions covering all of these topics were presented at the Hyatt Regency in Chicago, many to packed rooms in which every seat was taken and people were standing along the side and back walls.RETC is a biennial conference and one of the largest in the North America for the tunneling and underground construction industries. As such, it hosts a robust exhibit floor. This year 172 vendors occupied 205 booth spaces. The exhibit included everything from tunnel boring machine manufacturers, like Robbins and Herrenknecht, to the companies that supply all kinds of parts and services to the industry."

Sep 1, 2019

By Marlies Grimmer, Frank Amo Boateng

One of the challenges of mining is the concentration of heavy metals it releases into the environment through a phenomenon called Acid Mine Drainage. Freiberg is no exception due to its long mining activities. The European Union proposes that all rivers and streams must be in a good ecological status by the year 2027 but this would be difficult for large water sources as it would be economically unviable. Consequently, the approach of treating these waters at point sources would be of immense help and hence this column experiment on mine water treatment with carbon sorbents to remove zinc form the Rothschönberger Stolln. For this experiment three resins namely, APTsorb, activated coke, charred fermentation residues (which was produced by the Freiberg University of Mining and Technology) were analyzed through a simple column experiment to determine their sorption capacities. Through their sorption capacity as this experiment seeks to ascertain: we are able to make suggestions scientifically on the best material among the three for the future design of a treatment plant for the RSS. After the experiment whereby a 10 ml peri glass column was used, material A: APTsorb showed the least adsorption capacity (0.01 meq/g) and this could be attributed to the fact that the resin works well under pre-determined parameters such as pH and surface area. Material B: Activated coke showed a better sorption capacity (0.53 meq/g) in comparison to the basis value used for this experiment. Material C: charred fermentation residue which was produced by the University showed the most efficient capacity of (1.69 meq/g). This in comparison with the value used as the basis for this experiment showed that material C (charred fermentation residue) is very efficient for zinc sorption. pH values measured at the effluent of all the experiment were slightly higher than the pH measured in the initiating water.

Feb 1, 2024

By R. E. Vivas, J. A. Villa

"Located in the state of Colima, Peña Colorada is one of the largest iron ore operations in Mexico. The project is owned in equal parts by ArcelorMittal and Ternium. Though boasting a production capacity of 4.1 Mt/a (4.5 million stpy) of concentrate per year, Peña Colorada is faced with declining ore grades. In order to respond to this situation, Peña Colorada had to expand production even further. This expansion created various challenges that were overcome by the adoption and application of new technology. Examples of these technological innovations are discussed in detail in this article and include improvements in geo-modeling, mine planning, and mine operations. The successful implementation of these technologies paid for itself many times over, and has led to significant improvements in production and performance, while lowering the operating costs and reducing the variance between planning and execution.Project overviewPeña Colorada is a mining company that produces about 30 percent of the iron ore in Mexico. This project generates about 1,200 direct jobs and 3,000 indirect jobs, making a significant contribution to the local economy. Similarly, Peña Colorada invests in its local communities through numerous educational programs, scholarships, university agreements, social development, environmental agreements, etc. Peña Colorada’s operations consist of an open pit mine located in Minatitlán and a pellet plant located in the port city of Manzanillo, as shown in Fig. 1. Technological innovationsMost mining projects around the world typically follow the logic of “mining the next best ore.” Consequently, head grades tend to decline over the life of the mine. In the case of Peña Colorada, a decline in head grade combined with a decline in iron ore prices forced the operation to adapt to a new business environment and adopt new technologies to face these challenges. However, the first step along this process was to increase the confidence and reliability of the resource model. This task involved additional drillhole campaigns coupled with more detailed modeling techniques. Once the block model was completed, new optimization studies and production schedules were evaluated with new optimization tools that improved many aspects of the mine plan. The Peña Colorada block model has undergone 3 expansions to reflect additional information not available in the past. The model has expanded to the East and Southwest. The latest model expansion increased the total number of benches to 98 as a result of positive exploration results. Similarly, new geotechnical studies were prepared, which provided new guidelines for pit slope design, and new technology was implemented to monitor ground movement and slope stability. Two sectional block model views in Hexagon Mining’s MineSight 3D, along with the pit designs and geologic solids are shown in Fig. 2."

Feb 1, 2017