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By G. Nash

Despite further declines in production for some producers, 1986 proved to be a landmark year for the asbestos industry. The key event was the adoption of The Asbestos Convention by the Inter- national Labour Organization (ILO) and its 150 member countries. The document, entitled "Safety in the Use of Asbestos", reaffirms the international consensus on the "controlled-use" approach to chrysotile asbestos regulation. The decision of the ILO has come at a critical point in time. It represents a major turning point and provides an important building block for the long term future of the asbestos industry.

Jan 1, 1987

By B. C. Haydon

Manganese silver ores are well known to be refractory towards cyanidation. Various processes have been suggested for improving the amenability of these ores. A sulfurous acid pre-leach is one such process. This paper traces the development and implementation of the sulfurous acid pre-leach process for the retreatment of manganese silver tailings at Tonopah, Nevada. An account of the test work program is presented, followed by a description of the operating plant and specimen metallurgical performance. The paper also summarizes the history of the Tonopah tailings, their mineralogy and makes reference to previous application of the sulfurous acid pre-leach process.

Jan 1, 1984

By M. Yekich, W. R. Reed, G. Ross, M. Shahan

"Canopy air curtains (CAC) on roof bolting machines have been proven, through laboratory and field investigations, to protect miners from respirable dust, preventing dust overexposures. Another desired application is to develop a CAC that is mounted in the compartment of a shuttle car to protect the operator from dust. The challenges faced with this design include mine ventilation rates in tandem with the shuttle car tram speeds, causing cab airspeeds that may exceed 600 fpm, as found in this study of a central Appalachian underground coal mine. Prior research and laboratory testing indicate that successfully protecting a miner in high air velocities is difficult to achieve because the clean air from the CAC is unable to penetrate through the high velocity mine air and make it to the breathing zone of the operator. During this investigation by researchers from the National Institute for Occupational Safety and Health (NIOSH), dust concentrations of the shuttle car operator were measured. Also, air velocities experienced by the operator were measured using a recording vane anemometer. Results from the survey indicate that the highest exposure to respirable dust (2.22 mg/m3) occurred when the shuttle car was loading at the continuous miner, where there was an average airspeed of 157 fpm. While tramming, the operator was exposed to 0.77 mg/m3 of respirable dust with an average airspeed of 203 fpm. This study indicates that a CAC system can be designed to greatly reduce an operator’s exposure to respirable dust by providing clean air to the operator, since the majority of the operator’s dust exposure occurs in air velocities less than 200 fpm. INTRODUCTION NIOSH has issued a contract (#200-2015-63485) with Marshall University and J.H. Fletcher & Co. (Salem et al., 2016) to develop a canopy air curtain (CAC) for coal mine shuttle cars. The proposed design maintains a similar design to the roof bolter CAC by providing filtered air via a blower over the operator. The plenum, which will provide the uniform airflow over the operator, is anticipated to be built into the shuttle car canopy. One of the main interferences with a CAC is ventilation airflow perpendicular to the plenum airflow [Engel et al. 1987]. This ventilation airflow, if the velocity is significantly high, can shear the downward flow from the plenum. The shear caused by the ventilating airflow can reduce the effectiveness of the CAC by either disrupting the downward flow or allowing contaminated mine air into the CAC zone of protection."

Jan 1, 2018

By Malte J. M. Gurgel, Axel Preusse

The planning, construction, and monitoring of underground storage facilities is a key factor in meeting upcoming challenges as part of the energy transition from fossil fuels to renewables. Therefore, the many years of knowledge and expertise in ground control gained from coal mining are highly valuable for new mining and storage operations. For such applications, our previous work examined cavity registration, combining structure from motion and LiDAR through a case study in a former lead ore mine. Building on this, the results of this recent case study are discussed regarding the possible application in sites for nuclear waste disposal in Germany including a view on the situation in the United States. Photogrammetric methods are particularly suitable as part of long-term monitoring, which relies on both precise survey results and a large variety of detailed visualization. In order to gain a better understanding of the resulting application potential for holistic monitoring, both existing repositories sites in Germany and ones yet to be found are examined. This search and selection process for high-level nuclear waste disposal is studied in detail together with rules resulting from the (German) mining law, regulations, and other guidelines. Hereby, key requirements of photogrammetric products like oriented images, point clouds, and three-dimensional (3- D) models are identified for different case studies. The findings on accuracy and integrity of the generated models are not only of interest for future repository sites or underground pumped storage power plants, but also offers various possibilities for underground mining of coal and other commodities.

Jul 1, 2023

By Tom Ireland, Sumi Eratne

The approach to Risk Management during the procurement of major projects often has a significant outcome on the ultimate successful delivery of a project. The $NZ4.4B Auckland City Rail Link project is the largest and most complex transportation project yet undertaken in New Zealand. Risk management prior and during procurement was undertaken in accordance the ITIG Code of Practice for Risk Management of Tunnel Works (TCoP) and through the use of an Alliance Geotechnical Baseline report. This paper describes the measures taken during the procurement process to achieve certainty with respect to outcomes and minimise project risks whilst also achieving value for money. This included the use of cloud-based delivery of geotechnical data and 3-D geological models, reducing tendering costs and allowing a focus on risk mitigation measures during the tender rather than data management.

Jun 13, 2021

By H. Sevim

The utilization of high sulfur Illinois coal by utility plants has been decreasing since the enactment of 1990 Clean Coal Air Act Amendment. Illinois coal producers can make their coal saleable by offering the choice of taking the combustion by-products from the utility plants and placing them in the abandoned sections of their mines. To be competitive, however, coal producers need to select an environmentally acceptable transportation-handling-placement system through which the cost-per-ton of by-product disposed can be minimized. In this paper, a few such systems are presented. The favorable operating range of each system is determined in terms of distance and tonnage. A case study is given whereby cost analysis is conducted for an underground coal mine receiving by-products from two Illinois utility plants.

Jan 1, 1997

By C. Bailey Williams

Aragonite "sand," an oolitic lime-stone, is distributed throughout the Bahamas on the Grand Bahama Bank, adjacent to Southeast Florida. Bahamian deposits hold 75-100 billion tons of recoverable Aragonite. Aragonite's precipitation from seawater over 700 years ago assures low contaminates, making it a pure material for such industries as cement, glass, etc. A 90-acre, man-made production island was built south of Bimini, adjacent to ocean shipping channels mining is by cutterhead, suction dredge, dewatering, and stockpiling for further drainage and shipping. Aragonite is transferred to the U. S. East and Gulf Coasts via bulk carriers to points of sale.

Jan 1, 1978

By Morgan M. Sears, Gamal Rashed, Michael M. Murphy, Brent Slaker

A parametric study was conducted using FLAC3D numerical models to examine the impact of oblique loading on the strength and yield pattern of a stone pillar using two simplified geometry types. In type-1 the side walls of the pillars were assumed to be perpendicular to the roof and the floor, while in type-2 the side walls were assumed to be vertical. These two geometries are frequently used to simplify/model the creation of pillars in dipping mines. Results from the numerical modeling indicate that dipping pillars have reduced strength compared to horizontal pillars, and they are at an elevated risk of failure. Also, an asymmetric failure propagation pattern could be obtained depending on the interaction between the pillar width/height (W/H) ratio, seam dip, in situ stresses and pillar geometry.

By V. A. Mironenko

The combined study of ground water regime and rock deformations has resulted in the theoretical substantiation of the common principles for analysis of the hydrodynamic and geomechanical processes Within the scope of unique scientific direction -hydrogeomechanics (Mironenko and Shestakov, 1974). The hydrogeomechanical models are widely used now for the analysis and forecasting the extremely important processes connected with the safe and efficient mining operations, as well as with the protection of geological medium. Among these processes are: -deformations of the open-pit slopes and spoil dumps; -consolidation of rocks due to the ground-water pressure drop; -water-end-rock material inrush into mine workings caused by deformations of the undermined rock mass; -geodynamical processes due to the changes in ground water regime; -artificial hydrofracturing in rocks; -transformations of clay linings under the tailing ponds and other technical water basins.

Jan 1, 1990

By Ben Roderds

The Waneta Expansion Project (WAX) is located near the existing Waneta Dam site at the confluence of the Pend d?Oreille and Columbia rivers, approximately 10 km (6.2 miles) south of Trail, BC, Canada. The WAX owners consist of a partnership between Fortis Inc., Columbia Basin Trust and the Columbia Power Corp. This design-build project was awarded to SNC-Lavalin in late 2010 and is expected to be operational in mid-2015. The WAX consists of a new 335-MW powerhouse, including two new Francis turbine units, each generating approximately 167 MW. The powerhouse is located downstream of the existing Waneta Dam, and will make use of excess water that would otherwise be spilled during the runoff season. Water will be funneled to the turbines through an intake structure and two 10.5- m (34.5-ft) diameter, concrete-lined Penstock Tunnels. A 10-km (6.2-mile) transmission line will connect the powerhouse to existing electrical grids. Redpath/FKCI Waneta Tunnelers (RFK) was subcontracted by the heavy civil contractor, the Aecon/SNC Lavalin (ASL) joint venture, to excavate the two penstock tunnels and install the cast-in-place concrete liner. RFK is a joint venture partnership between J.S. Redpath Ltd., an underground mine contractor located in North Bay, Ontario, and Frontier-Kemper Constructors ULC, a heavy civil tunneling contractor based in Nova Scotia, Canada. Since penstock tunnel excavation was planned using drill-and-blast methods with a significant grade of more than 17 percent, the combined experience of these two contractors was a perfect match.

Mar 1, 2014

By H. R. Manouchehri

In flotation practices, as particles become finer, such as smaller than 20 μm, process efficiency declines markedly. Selective agglomeration of fine particles is a technique to enhance the recovery of fine valuable minerals in flotation circuits. Different agglomerating methods have been introduced and tested. One method that has recently received much attention is to make use of magnetic force to aggregate fine particles. A selective aggregation of fine paramagnetic particles, such as sulfide minerals, can be achieved in the high-intensity magnetic field prior to or during flotation. The method is simple, selective and effective for fine particles and has low operational cost, though a minimum magnetic susceptibility for fine grains is required to promote the process. In this paper, the implementation of the ProFlote magnetic conditioning device in Boliden’s Garpenberg old concentrator in Sweden, where a complex massive sulfide ore is treated, is presented and discussed based on Boliden’s Garpenberg plant. The results showed an increase in the flotation recovery of fine valuable minerals. Zinc (Zn) production was increased by between 1,100 and 1,500 t/a, while salable yearly silver (Ag) production was increased by 1,500 kg. The copper (Cu) grade in the final concentrate was increased by 1 percent, while reductions in its Zn and lead (Pb) grades were obtained. Moreover, considerable reduction in Zn deportment to the final tail was observed

By John Carr

The tremendous growth in grinding mill size and horsepower during the '70s demanded advancements in gear cutting technology and equipment for the '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' (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

By Earl L. Rau

Although the Sagasca deposit has been known for 76 years, the property was never put into successful operation because of various adverse factors including low market price for copper, legal entanglements, unsuccessful financial arrangements, and an inadequate metallurgical process. Late in 1963, Continental Copper & Steel Industries, Inc., obtained legal control of this property. Since that time there has been a concentrated effort to complete the necessary mine appraisal, process development, and engineering design, and to solve the legal and financial problems to bring this property into production.

Jan 1, 1970

By J. Kemeny, J. Lyons-Baral

"Point cloud technology is now an indispensable tool in geological and geotechnical data collection, interpretation and analysis. Open-pit and underground mines of all sizes are regularly collecting point cloud data as laser scanning (LiDAR) and photogrammetry surveying devices have become affordable and the workflows fast and efficient. Past challenges of large data processing and manipulation are gone with recent technological advancements in computer hardware and software. These innovations reduce file sizes, ease rendering requirements and allow for the implementation of real-time 3D viewers and surface meshing tools. With its ability to remotely and safely, rapidly and accurately extract large quantities of georeferenced and 3D-oriented data, point cloud technology provides numerous applications to the geomechanical field. The list of uses is continuously growing. This article specifically focuses on digital outcrop modeling and digital terrain engineering. Point clouds. The high-resolution and increasing availability of point cloud technology is rapidly improving open-pit and underground mines’ investigation, interpretation and characterization of site geology and rock mass properties (Kemeny et al., 2015; Lyons-Baral, 2012). LiDAR and photogrammetry are common remote sensing methods employed to measure the coordinates of surfaces in three dimensions (3D), providing the X, Y and Z locations and typically the reflective intensity and/or the visible three-band color of each point (Fig. 1).LiDAR uses either a time-of-flight or phase-shift measurement of a laser beam reflected off targeted surfaces and received back into the device.Photogrammetry generates point clouds by merging multiple overlapping photographs and uses stereographic plotting to define the locations of object points in 3D space. These methods can be deployed from airplanes, unpiloted aerial systems (UAS or drones), tripods, land vehicles and even in a mobile backpack shown in Fig. 2. RADAR, Total Station-Prism and other remote sensing systems also offer very precise “point clouds,” but this article does not address these due to their higher cost and lower versatility and mobility."

May 1, 2016

By Sean Hunter

Artificial Intelligence has a long history but is currently coming strongly into focus with new advancements. This leads to questions many people are asking: what exactly is AI, how can it be used effectively in mining operations, and what foundation is required to make AI implementations successful? In mining, many AI applications exist, from drill pattern optimization to predictive maintenance. However, many implementations struggle due to data integration challenges. Mining operations generate large amounts of data from many sources, such as fleet management systems, drill sensors, process control systems, and laboratory results. Unfortunately, this data often exists in silos where it’s difficult to get it out, making AI applications unable to leverage it. Worse still, tools that use AI don’t always provide their data back to the system, creating even further data silos. All these problems make it hard to take advantage of the data at the mine, slowing down and reducing the effectiveness of AI. This paper presents a comprehensive approach to organizing mining data using an AI-ready knowledge graph system. We will first explore the evolution of AI in mining, from early expert systems to modern machine learning applications. Then, we will detail how a knowledge graph can integrate business context, operational data, and AI models into a cohesive system that enables more effective AI implementations across mining operations. The proposed method has been developed considering both the unique data challenges faced by the mining industry, while also considering best practices learned from the AI field at large. By following this approach, it’s possible to better utilize existing data, getting higher quality and more complete results faster, and in a way that’s reusable and composable.

Feb 1, 2025

By Charles L. Allie

In June, 1980, Reserve Mining Company completed a 370 million dollar construction project which included process modifications required to reduce the silica content from nine to five percent by weight and increase the iron con- tent of Reserve's pellets from 62.5 to 65.8 percent by weight (dry basis); process modifications and additions required to implement "best available technology" water quality controls; and installation of "best available technology" air emission controls. The new process began operation on June 24, 1980 and is being optimized to meet design objectives. Dry cobbing, fine screening and flotation additions to the concentrating process have reduced the silica content of Reserve's pellet from nine percent to five percent by weight. The process reclaims and reuses all process waters, stores all tailings in a zero discharge tailings basin and meets all air emission standards.

Jan 1, 1980

By W. E. Anderson

As part of a larger study to identify factors influencing the practical operating life of wire rope used on large draglines in surface coal mining, field trips to operating surface coal mines were made during late 1975. Wire rope performance information was obtained from personnel at thirteen mine sites west of the Appalachians. Seventeen pieces of equipment, utilizing buckets ranging from 30-to 220-cubic-yard capacity, were documented. We have judged that U.S. surface coal mining draglines, 30 yards and larger, can be represented as 120 machines having 60-cubic-yard buckets, moving 1.8 x 10 yards of overburden during 6,650 hours of productive availability per year. Based on our limited field study, we have calculated that downtime resulting from rope-related causes averages 105.6 hours per year for each (typical 60-yard) dragline. The total lost production from this source alone is thereby estimated at about 25 x 10 yards annually. Although study findings did not reveal anything about dragline rope life that wasn't known or practiced by one operator or another, most operators could expect improved rope life by periodic review of their practices and by adopting or adapting one or more life-improvement measures employed at other sites. Since rope productivity was found to vary by about five to one, among the sites studied, we believe considerably improved average performance is possible. As little as ten percent overall improvement would mean increased national productivity exceeding two million yards of solid overburden removal, and associated savings in rope costs alone of some two million dollars annually, not to mention any reduction of labor-related expenses. This report outlines preliminary findings which may prove useful to many operators in extending wire rope life, thereby lowering expenses and increasing surface coal mining productivity. Some of these modifications or adjustments in maintenance/operating practices would not require capital investment. We did not find anyone who had tried cost reductions by using presocketed dump

Jan 1, 1977

By Howard Lum, Sergio Valles, John Bednarski, Gordon Enas, Jay Arabshahi

"Water drawn from the Sacramento-San Joaquin Delta provides water supply to 66 percent of California’s population and supports the state’s agriculture industry. The existing through-Delta water system is outdated and unreliable with environmental risk to some fish and wildlife species. The Bay-Delta Conservation Plan (BDCP) has been established to environmentally retrofit and modernize California’s water delivery system through the Delta by restoring habitats, constructing new diversion points in the north Delta and providing a means to transport water supplies under the Delta, rather than through sensitive natural channels.Under BDCP, the Delta Habitat Conservation and Conveyance Program (DHCCP) has developed several alternatives to convey water from the Sacramento River in the north to the existing pumping facilities in the south Delta through an isolated conveyance system. The new conveyance system would become an integral part of the State Water Project (SWP) and the federal Central Valley Project (CVP) by transporting water to the export pumping plants for each of these projects. The DHCCP is managed by the California Department of Water Resources (DWR), while state and federal water contractors provide technical support to the program.The initial conceptual study efforts on the overall program commenced in 2007 and examined various options for the proposed conveyance system. Several conveyance alternatives were analyzed at that time. The Conceptual Engineering Report published on Oct. 1, 2013 identified the modified pipeline/tunnel option (MPTO) as the preferred alternative to be included in the BDCP environmental documents. MPTO includes three river intakes and pump stations along the Sacramento River, various sizes of pipelines and tunnels, junction structures and two forebays that are capable of delivering up to 4 million gpm (9,000 cfs) from the Sacramento River to the SWP and CVP. The river intakes are located near Hood in Sacramento County approximately 64 km (40 miles) from Clifton Court Forebay (CCF) in Contra Costa County. This route would cross portions of Sacramento, San Joaquin and Contra Costa counties. Figure 1 depicts the configuration of the MPTO alternative."

Apr 1, 2016

By Y. C. Guan

The leaching kinetics of chalcopyrite in ammonium iodide solutions with iodine has been studied using rotating disc. The variables studied J include the concentrations of lixiviants, rotation speed, pH of the solution, reaction temperature, and reaction product layer. The leaching rate was found to be independent with the disc rotating speed. The apparent activation energy was measured to be about 50 kJ/mole from 15°C to 35°C, and 30.3 kJ/mole from 35°C to 60°C. Experimental findings were described by a kinetic model, and the overall rate was found to be: (formula)

Jan 1, 1997

By Yuting Xue, Todd Minoski, Daniel Su, Mark Van Dyke, Mark Mazzella, Steve Hicks, Zoheir Khademian, Nicole Evanek

Design of chain pillars in a longwall mine setting is one of the main engineering controls on the global and local stability of the mine. Challenges with roof instabilities, floor heaves, and pillar failures can be alleviated, to some extent, by careful design of gateroad configurations and chain pillars. This work investigates three different alternative designs in a three-entry-system gateroad configuration with an inter-panel barrier in a longwall mine in Virginia. Starting with the current design, which has faced challenges such as excessive floor heave, a geomechanical model developed in 3DEC software is validated by monitoring in-situ pillar stress in the yield, abutment, and barrier pillars in the mine. Next, three different chain pillar designs are evaluated in the model with a focus on roof sagging, floor heave, and pillar average stress. Results show the relationships among the alternative designs and instabilities associated with roof, pillar, and floor in the study mine, providing insights for optimizing longwall mining designs in deep-cover settings.

Feb 1, 2025