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By Chengliang Jliang, B. K. Parek, Xuxin Shao

Of the impurities present in phosphate ore, dolomite is the most difficult to remove due to the similar chemical compositions of the impurities and also adsorption of dissolved species of dolomite onto phosphate. A new amphoteric surfactant was found to be a suitable collector for separation of dolomite from phosphate. Flotation results showed that the new amphoteric collector had a high flotation selectivity for dolomite in wide pH ranges. The flotation study of francolite and dolomite in each other's supernatant demonstrated that the dissolved ions had little effect on the selectivity of the new collector, but were detrimental to the flotation separation using sodium oleate as collector. A phosphate concentrate with 35.2% P2O5 with 90% recovery was obtained using 290 g/t of the amphoteric collector from a mixture of francolite and dolomite containing 26.2% P2O5. The rejection of MgO was 81.41%.

Jan 1, 1999

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

In this study, a parametric study was conducted using FLAC3D numerical models to examine the impact of oblique loading, generated from seam dip, on the strength and the failure propagation pattern of a stone pillar using two simplified geometry types. In type 1, the sidewalls of the pillars were assumed to be perpendicular to the roof and the floor, while in type 2, the sidewalls of pillars were assumed to be vertical. The complex pillar geometry in dipping mines was frequently modeled using these two geometries. To capture a complete picture of the effect of seam dip on pillar stability, the modeled width-to-height (W/H) ratio of the pillars, in situ stress field, and pillars roof/floor interfaces were systematically varied to account for the potential distribution of values for these parameters across the underground stone mines in USA. Results from the numerical modeling indicate that dipping pillars have reduced strength compared with horizontal pillars. Also, an asymmetric failure propagation pattern could be obtained depending on an interaction between the W/H ratio, seam dip, in situ stresses, and pillar geometry.

Feb 5, 2021

By A. Adu-Acheampong

Photogrammetry and laser scanning has been employed at a number of Newmont mine sites to mitigate risks associated with conventional structural mapping, determining the geometry of voids from old underground workings, and generating topography in areas of slope instability. Laser scanning has also been used to evaluate as-built pit slope configurations with respect to design assumptions, operational practices, and rock fall potential. Recently, remote sensing applications carried on an unmanned aerial vehicle (UAV) were used to generate base topography at some Newmont sites. UAV are generally more convenient and less expensive and can be utilized in areas where cloud cover prevents manned aerial photography missions. This paper discusses these applications, and provides commentary on their benefits and limitations based on recent experience.

Feb 27, 2013

Surface subsidence that results from longwall mining can be large magnitude and can affect significant areas. Conventional methods for subsidence monitoring include leveling, global positioning system (GPS), and photogrammetric surveys. Remote sensing techniques, including aerial LiDAR, terrestrial laser scanning, and satellite-based differential interferometric synthetic aperture radar (DInSAR), are also used to measure deformation associated with subsidence. DInSAR data are different than data from conventional subsidence surveys. Images capture data over large areas (hundreds of kilometers), and each pixel (data point) in an image quantifies the average displacement over an area of square meters. DInSAR data can have fairly high time resolution; imaging periods typically range from weeks to months.

Jan 7, 2020

By Botelho Junior, Amilton Barbosa, Denise C. R. Espinosa, David B. Dreisinger

Copper and cobalt can be found on nickel laterite ores, and cobalt can be found also on copper ores, and many contaminants such as iron, aluminum, and magnesium are associated with these ores. In hydrometallurgical process, a purification step is necessary after leaching due to the presence of these impurities. Chelating resins are more selective for some metals than others, making them more efficient than cationic resins. This overview discusses chelating resin applications to recover copper, nickel, and cobalt from mining process and mining tailings and the effect of contaminants in leach solution. Chelating resins with iminodiacetate functional group can be used for selective copper recovery, and both iminodiacetate and bis-picolylamine resins are highly selective for nickel and cobalt. Chelating resins with the same functional group can have different performances on the kinetics of loading, because of variations of structure, the density of functional group, and degree of cross-linking. This article reviews commercial chelating resins that can be applied in leach solutions with different compositions, and also possible innovations for uses of chelating resins to recover metals from mining process and mining tailings.

By R. J. Sweigard, C. T. Justice, T. Beckham, E. D. Thompson, T. C. Hopkins

Fine coal refuse is often pumped, as slurry, into surface impoundments as a means of permanent disposal. As the available volume is filled, the height of the embankments are frequently increased. Many times the additional embankment material is placed upon consolidated fine coal refuse. There has been some concern about the long-term effect of consolidation of this material at or above the liquid limit upon its shear strength. A laboratory investigation was performed using three different types of fine coal sluny taken from Central Appalachian coal preparation plants. The refuse was consolidated in 10-foot plexiglass columns under incremental amounts of surcharge loading. The incremental loads were designed to simulate the effect of increasing the height of a refuse embankment on top of the consolidating coal slurry. After the refuse in the columns had consolidated for several months, the columns were cut apart and triaxial tests were performed on both the consolidated material and unconsolidated material for comparison of their shear strength parameters.

Feb 24, 1997

By Z. Mullard

The introduction of social media platforms has ushered in a new era of interaction and information exchange, which impact business-to-society relationships. Mining companies are closely watching these platforms, as the industry takes a cautious approach to control flows of information. This paper explores the risks, challenges and opportunities of using social media, based on a qualitative mixed methods investigation with stakeholders from the Canadian mining industry. Generational and language barriers, misunderstanding and limited motivation from regulators make implementing social media platforms challenging and risky at an organizational level. The benefits of social media include being able to mobilize communities and share information in real time. Despite the challenges, the study found that 62% of mining stakeholders are incorporating social media tools, mostly in an ad hoc manner. Flexible strategies for transparent communication and public engagement are creating new opportunities for information exchange.

Jan 1, 2011

By Ji Fang, Chong Fan, Fengrui Wang, Dongxin Bai

Unmanned mining technology in underground mines offers high efficiency, safety, and low cost. However, ground operators face challenges in accurately perceiving the underground environment through videos. This paper presents an augmented reality (AR) platform developed to enhance the unmanned mining process. The platform uses cameras and 5G technology to transmit high-fidelity video streams to the ground, where key targets are identified and virtual models are registered in the video to enhance the real scene. Tests in the Xinli stope of the Sanshandao gold mine showed the platform’s effectiveness in improving ground operators’ perception and production efficiency.

Jan 30, 2022

By L. Mead

Dimension stone is a natural stone (granite, marble, limestone, sandstone and slate) that can be quarried, cut and shaped to conform to acceptable industry standards for size, consistency and durability. There are numerous outlets for the finished product in exterior and interior architectural and design applications. A continued growth market is with residential usage— particularly in new, upscale construction. This has become a competitive market between domestic producers and lower cost imported products. These imported products have become available at many of the building supply retail outlets and have increased the use of stone in residential construction and renovation. The traditional architectural application of dimension stone is tied to commercial and institutional building construction trends and market. There has been a noticeable increased usage of stone in the Sun Belt. This stone is usually supplied by local fabricating shops. It is used in the exterior and interior of shopping malls. This market generally uses local stone sources. It has increased the demand for sandstone, limestone and quartzite in this region of the country.

Jan 1, 2005

TABLE TUNNEL NAME OWNER LOCATION STATE TUNNEL USE LENGTH (FEET) WIDTH (FEET) BID YEAR STATUS Gateway Tunnel project Amtrak Newark NJ Subway 14,600 24.5 2015 Under study

Sep 1, 2013

By Lee W. Abramson, Kenneth P. Akins

The authors have accumulated published data on residual soil and rock tunnels in the United States and have compared it to transit tunneling experience in Atlanta, Georgia, and tunnels in other soil and rock conditions. Two 6.1 meter (20 foot) diameter shield driven, compressed air tunnels were constructed for the Metropolitan Atlanta Rapid Transit Authority (MARTA) connecting the Five Points Station (central hub) with the Peachtree Center Station (first station on the north line). Because of the historic multi-story structures above the tunnels and the variety of subsurface conditions, a comprehensive ground monitoring and observation program was conducted. Conclusions are drawn regarding residual soil and rock ground response due to tunneling. Comparisons are made to ground response due to tunneling in other soil and rock conditions.

Jan 1, 1983

By G. T. Adel, J. D. Miller, C. L. Lin

Washability analysis determines the maximum separation efficiency that can be achieved in the operation of coal preparation plants. Unfortunately, there are no on-line techniques for determining this most fundamental information. It now appears possible to determine coal washability on-line through the use of x-ray computed tomography (CT) analysis. This paper presents the results for the development of a CT-based, on-line coal washability analyzer. The development of appropriate hardware and software necessary to adapt a CT analyzer for use in determining coal washability is discussed. Testing of the analyzer using well-characterized coal samples is presented.

Jan 1, 2000

Tellurium (Te) is one of the least abundant elements in the crust and tends to form minerals associated with copper, lead, zinc and iron sulfide deposits. Today, most tellurium production comes from the anode slimes and other wastes generated in metal refining. Most of the current tellurium produced in the world is used as an alloying agent in iron and steel, as catalysts, and in the chemical industry. However, future demand and production could increase because tellurium is increasingly used in solar panels and some electronic devices. Tellurium minerals are found in Au-Ag districts in New Mexico, but were not considered important exploration targets in the past. In New Mexico, tellurium is found associated with porphyry copper deposits in southwestern New Mexico and with Au-Ag veins in the Eureka, Sylvanite, Organ, Lordsburg, Steeple Rock, Wilcox, Mogollon, Chloride, Cuchillo, Hillsboro, Zuni Mountains, White Oaks, and Nogal-Bonito districts. The only tellurium production from New Mexico has been from the Lone Pine deposit (Wilcox district), where approximately 5 tons of tellurium ore was produced. Gold-tellurides are found with gold, silver, pyrite, and fluorite in fracture-filling veins in rhyolite at Lone Pine, with reported assays as much as 5,000 ppm Te. Other districts in New Mexico have potential for tellurium, but require field evaluation.

Feb 27, 2013

Where space is limited, as it is throughout most of the northeastern United States, new construction either takes place high above street level, or below it. In Lower Manhattan, NY both kinds of expansion can be found in abundance. That is good news for the nearly 200 attendees at the George A. Fox Conference, presented by the Underground Construction Association (UCA) of SME at the Graduate Center, City University of New York, on Jan. 30. Among the many projects taking place in Lower Manhattan?s massive trans-formation process, are expansions to the city?s vast underground network of subways and other tunnels. ?New Yorkers either live on the ground or below it,? said keynote speaker Charles J. Maikish while explaining how an attempt to build above street level walkways never caught on in the city. Maikish is the executive director of the Lower Manhattan Construction Command Center. His job is to oversee the $22 billion project that will transform the island by 2010. From the construction of Freedom Tower at the site of the fallen World Trade Center buildings, to the expansion of the Second Avenue Subway, the extension of the East Side Access, No. 7 line, the new trans-Hudson line and numerous waterway tunnel expansions, including City Water Tunnel No. 3, the task Maikish is charged with is a huge one. He is primarily responsible for coordinating the scheduling and staging of the overall rebuilding plan, along with the day-to-day coordination of construction work down-town. He places particular focus on mitigating impacts on the environment and mobility, maintaining and improving access and alleviating congestion of any kind related to construction. At the time of the Fox Conference, there were 59 projects under way in Manhattan. All of those projects need things like concrete and steel delivered to sites in very tight working environments. And some need the equipment in even tighter spaces. ?This is not just about the recovery of Lower Manhat-tan (from the 2001 terrorist attacks) but this is a plan to restore it and to maintain its integrity,? said Maikish. ?I think that is the appropriate response to the terrorist attacks.? When Freedom Tower is completed, it will stand 541 m (1,776 ft) about the skyline. That will be a strong statement to the world about America?s strength. But it is the work that takes place much lower that was of interest to the conference attendees. On this respect, Maikish said Manhattan?s efforts below ground aim to provide relief to the city?s street level congestion and to make sure Manhattan ? already essential to the economy of the United States and the world ? stays current by upgrading the existing telecommunications and technological network while also allowing room for growth in that area.

Jan 1, 2007

By Dan Witkowsky

Beginning on June 11, 2007, as many as 36, kindergarten-to-grade-12 (K-12) teachers will participate in a program designed to educate them all about the mining industry. The 39th Annual A Total Concept of the Mining Industry – All About Mining, will be conducted by the Colorado Mining Association Education Foundation, Inc. (CMAEF) and the Office of Special Programs and Continuing Education (SPACE) at the Colorado School of Mines. This flagship program includes four intensive weeks at the Colorado School of Mines. During that time, more than 75 volunteer lecturers will “educate the educators” about mining and its importance to the United States and the world. During the learning process associated with obtaining a basic understanding of mining and all its aspects, the teachers will be hosted by hundreds of other industry professionals at 10 Colorado mining operations. Also visited will be a government earthquake center, a museum of mining and industry, an earth mechanics laboratory, a metallurgical research center, a metallurgical concentrator, an electric power plant and a steel mill. Questions before, during and after visits will be answered by another select group of volunteers who will travel with the teachers to the various sites.

Jan 1, 2007

By G. Deissman, S. Kistinger

For the last 15 years environmental Life-Cycle Assessments (LCA) have increasingly been used to evaluate the environmental performance of industrial processes and products and have been employed as a basis in decision making processes in the public and industrial sector. However, assessment methodologies for environmental protection measures and reclamation/remediation measures with respect to their consumption of natural resources are generally poorly developed. In this presentation a methodology for LCA of environmental protection measures and remedial actions, respectively is suggested, using the remediation/reclamation of mining sites as an example. Key aspect of this approach is the development of an evaluation method appropriate for environmental protection measures, which links the various impact indicators recognised in the impact assessments and allows their integrated assessment.

Jan 1, 2005

By M. H. Weinecke, B. P. Faulkner

This paper will discuss the process for making lightweight aggregate, the waste materials that make good lightweight aggregate, the chemistry of making lightweight aggregate and finally a discussion of the commercial prospects for making lightweight aggregate from wastes. Svedala Industries has been making lightweight aggregate (LWA) from waste materials for the last ten years. Many clay-like materials, such as coal-fired boiler ash and washings from a granite quarry, can be used alone or with additional waste materials to produce a commercially saleable LWA.

Jan 1, 2001

By L. L. Chasko

A mine fire is one of the most challenging safety issues facing a mine operator and can occur at any location underground. The National Institute for Occupational Safety and Health (NIOSH) and the Twentymile Coal Mine, Colorado, conducted in-mine experiments to determine the capability of high-expansion foam for addressing underground fires. The tests were conducted in sloping entries with high-capacity diesel-powered foam generators. The following results were observed: a well-designed, maintained, and properly operated high-expansion foam generator can propagate a foam plug hundreds of feet in steep upward sloping (20 pct) multiple entries against a ventilation pressure; stoppings and partitions designed to contain the foam plug in upward sloping entries must be substantially constructed; and the predicted quantity of foam concentrate can be significantly less than the actual amount used due to foam losses, such as bubble breakage on dry surfaces. This paper describes the production of high-expansion firefighting foam and discusses the in-mine experimental tests and results. DISCLAIMER: The findings and conclusions in this report are those of the author(s) and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Jan 1, 2009

By A. Karami

It is well established that an ordered sequencing of charge initiations in a blast pattern is an important design consideration that affects blasting performance. Delay times must be chosen such that damage to the rock mass is controlled. The accuracy of delay detonators is also of major concern. A large scatter could lead to an incorrect blast sequencing that would lead to damage to the rock mass causing increased over-break, degraded fragmentation, increased fly-rock and poor vibration control. In this study, the effect of using accurate delay detonators on the explosive energy generated is investigated. For this purpose, power spectral density of the blast vibration for delayed shots are calculated and compared with the case where holes are shot at the same time (no delay). At the end the results are presented and discussed.

Jan 1, 2000

By J. Brent Hiskey

Thiourea is a reagent capable of complexing gold and silver. With the proper oxidant, thiourea can effectively dissolve metallic gold and silver. A thiourea leaching system possesses potential advantages over conventional cyanidation including acidic solutions instead of alkaline, cationic complexes in contrast to metal-cyanide anoionic complexes, and faster leaching rates with acidic solutions of thiourea. Generally, the rate of metal dissolution in thiourea solution is fastest when ferric ion is employed as an oxidant. Acidic thiourea solutions for certain applications could offer a nontoxic and noncorrosive option for processing gold and silver. This paper provides information regarding the fundamental chemistry of the acidic thiourea system, and reviews the dissolution of both silver and gold in acidic solutions of thiourea. The recovery of gold and silver from acidic thiourea solution is discussed.

Jan 1, 1981