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By R. W. Sims

"He?s an SOB, but he's my SOB." Many of us have heard this line in reference to attorneys, and can appreciate the humor. However, the thought reflects a deeper attitude that lawyers should be used for attack purposes in the legal system or the regulatory process. Often, more permitting progress can be made with tact and flexibility than with inflexible, overly aggressive strategies. Usually, administrative hearings or other litigation work to the disadvantage of the applicant. Thus, I have concerns about approaching any permitting system with a hard-line attitude. On the other hand, the project team must always be prepared to defend permit applications and present a legally adequate case at public meetings, administrative hearings, or judicial proceedings. This paper discusses a number of strategies intended to increase the probabilities for successful permitting, whether opposition is informal or highly organized.

Jan 1, 1990

By D. E. Larson

The U.S. Bureau of Mines has developed a image analysis methodology to correlate the energy consumed during the grinding of an ore to the mineral liberation achieved. Energy consumption values are obtained using a laboratory-scale ball mill equipped with a torque sensor, and an automated image analyzer is used to determine the liberation present in ground products. By combining liberation information with energy consumption data an appraisal can be made of the energy required to liberate the mineral(s) of interest. Results of tests performed on a complex sulfide material determined the effects of grind duration on the liberation achieved and the energy efficiency.

Jan 1, 1995

By Erik Vlot

"The mining industry has recognized the advantages of high density backfill or ‘paste’, which is typically pumped with a hydraulically driven piston pump. Due to the discontinuous flow of this type of pump, pressure pulsations can occur in the discharge line. Pressure pulsations are an undesired phenomenon in pumping installations for a number of reasons that include: damage to the pumping system; piping and supports; disturbing noise levels; and even safety risks for operators and maintenance personnel.This paper describes an advanced system on the GEHO® piston pumps, which will prevent virtually no pressure pulsations from occurring, rather than merely reducing the already existing pulsations.INTRODUCTIONThe first GEHO® hydraulically driven piston pump was developed in the mid-1970s. It was an industrial design pump designed to operate in the high-standard industrial environment with regards to operating hours per day, duties, maintenance and lifetime of the pump and spare parts. This type of pump has a proven track record and has been further developed for the type of applications that we are describing today. The special feature of this pump type is its ability to pump extremely viscous slurry with solids content of up to 90% by weight, at high pressures. Typically, in the mining industry, this pump is used for tailings transportation, with a focus on mine backfill and is often referred to as a paste pump.In the 1980’s the hydraulically driven piston pump made its entry into the application of mine backfill, thanks to the high discharge pressure capabilities enabling the mines to pump higher density (i.e. higher solids concentration) slurries and pastes over longer distances.Part of the ongoing development was (and still is) the increase in discharge pressure and flow capacity to comply with the ever growing demands for high power piston pumps. In line with the technological developments and increase in performance duties, the popularity of this pump type increased significantly and many other industrial applications have discovered the benefits of this pump type.Together with the increase in pump discharge pressures and flow capacities the effect of an undesired phenomenon also increased: the phenomenon of pressure pulsations. Before we explore this subject in more detail it is important to first understand the design and the characteristics of a hydraulically driven piston pump."

Jan 1, 2017

By N. Merriam

This report describes Koppelman's work to develop the K-Fuel® Series C Process used to dry and stabilize Powder River Basin coal. It also contains summaries of the results of bench-scale and pilot plant tests conducted to prove the Series C Process. The process is being used by the KFx-Thermo Ecotek partnership for a 500,000 ton per year commercial plant that has been constructed near Gillette, Wyoming. The plant is presently undergoing shakedown.

Jan 1, 1997

By John C. Cook

There is pressing need for better means of exploring ground conditions ahead of mining. Exploration drilling has the drawbacks of high cost and a seriously restricted sampling zone. Traditional geophysical exploration methods including gravity, magnetic and resistivity techniques have been used with some success underground, but all give poor target delineation relative to range, since they depend upon minor distortions of a potential force field. Much greater ratios of resolution to range can, in principle, be obtained by employing electromagnetic or seismic radiation as the exploring agent. This is because propagation time delays can be used to measure range accurately, and to separate the small effect of a distant target from the much larger effects of nearer targets and of the transmitter. Seismic waves have long been used with great success in exploration for petroleum, and recent research on their application underground is promising. Electromagnetic (radar) waves have been very successfully used for detection and location through the air and outer space, and have also explored through polar icecaps more than a mile thick.l It is not generally realized that below the soil many rocks are also somewhat radar-transparent, and that radar can be used for exploring such rocks, once a quarry, a mine, a borehole, or other means of access has been opened. Radar waves are reflected by any boundary or object where they encounter a large change in electrical properties.2 The usual cause of such a change is a difference in moisture content. Radar waves passing

Jan 1, 1972

By A. B. Cecala

The Bureau of Mines has been performing research to lower the dust exposure of workers at mineral processing operations for a number of years. This research has mainly been directed at source control techniques in an effort to lower a worker's dust exposure at a particular job function. In some cases, this control technology provided a carryover effect in lowering the exposure of workers at other locations, but for the most part had very little effect in lowering dust levels throughout an entire mill building. Recently, the Bureau became aware of several mineral processing operations having problems with high over-all mill dust levels. These operations were all using baghouse-type collectors to address their most serious dust contamination areas. Although these major dust sources were being controlled, there were numerous minor dust sources that were not. These minor dust sources were causing dust levels in these operations to gradually increase as the day or shift progressed. The intent of this work was to determine general guidelines and design criteria for operations that may be interested in implementing a total mill ventilation system. Most mill buildings can be considered a closed system and thus any dust that is not being controlled within the structure, will cause dust levels to gradually increase over the shift. A total mill ventilation system should be designed to draw clean make-up air in near the base of the mill. This air provides general purging and may clear some dust laden areas throughout the mill structure. This air should be discharged at or near the top of the structure, where it is not a contaminant to plant personnel working outside. Without this exhaust system, dust can exit the building through open doors, windows, etc., and contaminate outside plant workers. This dust can also be recirculated back into the mill building causing additional contamination problems. A total mill ventilation system is not a stand-alone technique, but is a supplemental technique to assist other localized dust control systems.

Jan 1, 1994

By G. L. Mowrey

In addition to developing various types of coal interface detection systems, the U.S. Bureau of Mines is actively involved in developing a coal rib thickness monitoring system for high wall mining applications. One particular system that appears to show promise uses a ground-penetrating radar system to detect the coal-air boundaries of coal ribs. Based on preliminary laboratory and field tests, results indicate that this method can be applied successfully in highwall mines to maintain a constant rib thickness. The coal seam should be relatively clean in the vicinity of the antenna (e.g., have minimal partings or dirt bands) for best results.

Jan 1, 1995

In cold regions rinsing of spent cyanide leach heaps is stopped during winter and is resumed again after snow melts. The effect of this idle time on the overall cyanide removal process was studied in this work. Samples were collected for rinsing tests from one heap at the Ryan Lode Mine of Citigold Alaska, Inc., near Fairbanks. The material was tested for cyanide removal a large column, 1.22 m high by 20 cm square, and in a small column, 1.22 m high by 10 cm in diameter. The rinse water was analyzed at regular intervals to determine the rate of cyanide removal from the solids. It was found that diffusion plays a major role in the removal of cyanide from the ore particles. Calculations showed that the insulating effect of the snow cover on the heap provides an excellent moderates the interior temperature of the heap, and would be expected to help the progress of the diffusion reaction during winter. The result expected result wil1 be higher cyanide values reporting to the rinse water after snow-melt.

Jan 1, 1993

By J. W. Shield

Refractory sulfide flotation or gravity gold concentrates are coated onto a sized support matrix and placed in a heap configuration for biooxidation. The surface coating is typically less than 0.05 in. thick and the support matrix is preferably composed of 0.375 to 0.75 in. diameter material. The exposed thin coating of sulfides reduces biooxidation rate limitations due to oxygen mass transfer. The large spaces between matrix particles reduce resistance to fluid percolation and aeration in the heap. The capital and operating costs for this biooxidation configuration are significantly less than for concentrate biooxidation in stirred tanks. After 30 to 90 days of biooxidation, sub- sequent gold recoveries exceed those seen in whole ore heap biooxidation and are comparable to recoveries obtained from stirred tank biooxidation processes. Results from laboratory and pilot testing indicate that this technology is a viable alternative for pretreating sulfide refractory gold ores.

Jan 1, 1997

By R. J. Sweigard

One possible alternative for disposal of flue gas desulfurization (FGD) by-products is use as backfilling support material in highwall mine adits. The finite element method was used to analyze the variation of stresses and displacements within and around a highwall adit backfilled with FGD materials. The engineering properties of the rock material and the optimum mix proportioning of the FGD materials were obtained from laboratory tests. Finite element analyses show that, for the case in question, the roof displacement would decrease about 48 percent and the peak stress could be decreased about 58 percent. The study indicates that fairly weak FGD materials can eventually lead to stability of backfilled highwall adits.

Jan 1, 1996

By K. Boakye, T. Newman, P. Bláha, M. B. Toelle

"This paper presents a quarry optimization plan using a block model and an in-house development quarry scheduling and optimization software (QSO Expert) to help improve quarry operations at Crystal River. The Crystal River Quarry is an underwater quarrying operation that barges limestone via the Gulf of Mexico, as the main source of raw material to a cement plant in Theodore, Alabama. To improve the quarry operation, an evaluation was completed to optimize the quarry planning and extraction procedures of the quarry. In order to achieve this, additional exploration drilling campaign was implemented, a new block model was re-calculated and the latest version of QSO Expert software was used. The primary economic impact is a higher recovery of limestone reserves; sustainability of resources, corresponding longer quarry life. Secondarily as the limestone is mined underwater and stockpiled above water, drainage reduces moisture content achieving direct cost reduction on limestone shipping. In addition, a considerable reduction in operational cost was achieved due to a significant decrease in consumption of electrical energy, reduced dragline maintenance costs and reduced dragline movements within the operation. INTRODUCTION Holcim is a Swiss-based global building materials and aggregates company. Founded in 1912, the company expanded into France and then throughout Europe and Middle East during the 1920s. In 1922, Holderbank, as the company was then known, expanded beyond the Swiss borders into France. By the end of the decade Holderbank held stakes in Belgium, Germany, the Netherlands, and Egypt (Holcim History 1912-2012) Positions in Lebanon and South Africa soon followed.. Holder bank later expanded in North America in the 1950’s. In the late 1970s and early 1980s, Holderbank continued its expansion in Latin America, Asia and Spain for the first time. The company expanded into Eastern Europe and experienced a boom in Spanish construction preceding the 1992 Summer Olympics. By 1986, Holderbank was the world's largest cement manufacturer. In the 1990s, the company consolidated its European holdings as the American market drove growth. Expansion into Eastern Europe and Russia continued (Holcim History 1912-2012). In 2001, the company changed its name from ""Holderbank Financière Glaris"" to Holcim (short for Holderbank ciment) (Holcim History 1912-2012). Holcim expanded by purchasing Aggregate Industries entering into the United Kingdom for the first time. That year, the company also expanded into India by acquiring a stakes in The Associated Cement Companies (ACC) and Ambuja Cement Eastern. In 2008, Holcim became the largest shareholder of China's Huaxin Cement with a 40% stake. In 2009, they acquired Cemex Australia. In 2014, Holcim and Lafarge announced they had agreed to terms on a ""merger of equals"" valued at nearly $50 billion in 2015. The new company LafargeHolcim based in Switzerland has a manufacturing capacity of 427 metric million tons a year."

Jan 1, 2017

By D. Marino

Over the last 20 years, the manufacturing sector of our country has been called upon to comply with ever core stringent environmental standards. The primary metals sector was particularly hard hit early on, to develop the technology, acquire the equipment, and implement the programs to eliminate or reduce the by-products of metal making. To this end, through a combination of technological innovation and extensive capital expenditures, the metals industry has met, and in many cases, exceeded the minimum standards. It is to this escalating cost - liability exposure issue - that Dereco has addressed itself. As we move into the decade of the 90's, the challenge facing the metals industry concerning the environment will be even more difficult than the previous decade. To focus in on one major aspect of legislated environmental regulations, the issue we will address today is; now that the by-products of metal production have been identified, accounted for and collected, how are they to be disposed of? During the course of this presentation, actual data will be presented from our 4 1/4 year on-site experience at J & L Specialty Products

Jan 1, 1992

By Javad Sattarvand, Amin Moniri-Morad

Predicting equipment failure behavior plays a critical role in providing a safe operation. Although various reliability evaluation methods are available for estimating failure behavior profiles, these approaches are based on mathematical formulation, leading to actual operation simplification and improper estimation of failure trends. This study proposes a discrete-event simulation (DES) approach to model fleet failure behavior. This approach can model the maintenance strategies in multi-component systems with minimum simplifications. In this regard, the first step was to collect a historical failure time dataset (e.g., the time between failures). Then, the DES model is established to predict the severity of failure events and design maintenance strategy considering actual operation circumstances. Afterward, the maintainability analysis was performed to estimate equipment downtime and availability. The achieved results showed that the system availability was about 85%. Also, the findings demonstrated that the DES could efficiently predict the equipment failure behavior using various stochastic events.

Jun 25, 2023

By M. A. Cornachione

The west central upper Peninsula of Michigan contains a large resource of graphitic slate. The slate has potential industrial use as a substitute for shale currently used in the production of portland cement. Some of the unweathered slate, however, has a high concentration of pyritic sulfur which can create emission problems when processed in a kiln. A low cost method to reduce the sulfur content of the slate through the optimization of pyrite oxidation in a bio-heap leaching operation was investigated.

Jan 1, 1992

By Daniel E. Collins

Massive banded Fe-Zn-Cu-Pb sulfide deposits in the Bagdad are associated with metamorphosed eugeosynclinal mafic volcanic and intrusives rocks Precambrian age. The geologic environment is very similar to that of the Jerome-Prescott area which lies 70 km. east of Bagdad. Mining of massive sulfides deposits began in 1917 on the Copper King mine in spite of its early discovery and the discovery of the Old Dick mine in 1882. The first shipments of zinc ore from the Copper King were hand sorted and averaged 46.89% Zn, 5.7 oz. Ag, 3.58% Pb and 1.68% Cu. Oxidized copper was first produced from the Old Dick mine in 1943~ In all, five deposits of massive sulfide ores have been mined in the Bagdad for a total production of nearly 2 million tons with an average grade of 12.0% Zn and 3.6% Cu. The largest deposit, the Bruce mine is currently closed because reduced metal prices and has produced a total of 823,000 tons of Zn-Cu ore to date. Mining of massive sulfide ore in the Bagdad area is presently idle. However, the potential for locating yet undiscovered ore bodies is good. Exploration for new ore bodies is difficult at best due to the complex geologic history of the area, the small size of individual ore bodies and lack of understanding as to the formation of massive sulfide deposits. The purpose of this investigation was to obtain a better understanding of the host rock formations through detailed geologic mapping, petrography and chemical analysis.

Jan 1, 1977

By Luis Fernandez-Deza, James Hawn, Dustin Mount, Jean-Marc Wehrli

The RiverRenew Tunnel System project in Alexandria, VA forms part of a CSO scheme aimed at reducing overflows of combined stormwater and sewage into the Potomac River during storm events. A major piece of the project is a 12-foot internal diameter tunnel of approximately 12,000 feet length lined with a single-pass precast concrete segmental liner and excavated by an Earth-Pressure Balanced Shield TBM. The tunnel lies between 120 to 140 feet below grade in the clays of the Upper Potomac Formation with occasional dips of more granular, saturated soils of the Terrace Formation and the Alluvium. The TBM is launched from a figure-8 configuration Pumping/Screening Shaft located within AlexRenew’s operational Water Resource Recovery Facility. This paper discusses the challenges encountered during the launch of the TBM in short mode within a highly congested site and from narrow deep shafts.

Jun 13, 2023

By Anil K. Ray

Roof falls are one of the greatest hazards in underground coal mines worldwide. Due to stringent safety measures and extensive support system development, roof falls have been reduced significantly but they still persist in many underground coal mines. Some of the roof falls initiate with cutter roof or guttering. In the past, many factors have been identified as being responsible for the development of cutters and roof fall. These responsible factors can be broadly classified as stress related or non-stress related. In this paper the finer details of mining technique have been taken into consideration for better understanding of cutter roof and roof fall problems. Three dimensional finite difference modeling has been used to explain the mechanism of cutter development. Strain softening material behavior has been used to realistically simulate the cutter formation, and common cutting sequences as implemented in the field have been simulated. This was done with an objective to determine whether the cutting sequence has really any significant control over cutter formation or not. In addition to cutting sequences, the effect of cut length is also studied. The effect of step cutting and turning of crosscut into and away from major and minor horizontal stresses is also examined to see its influence on cutter development.

Jan 1, 2009

By H. Sevim

Placement of coal combustion byproducts into abandoned sections of underground coal mines for the purpose of subsidence mitigation has been investigated in Illinois. Several handling and transportation systems have been examined. Prototype pneumatic and hydraulic placement systems have been developed and demonstrated. The demonstration site, Peabody No. 10 mine in Pawnee Illinois, is selected as a case study. It is found that, for a project of 5 years, transporting 150,000 tons of byproduct annually from a power plant located 32 km (20 miles) to the mine would cost $1.80 per ton and placement into underground would cost $3.07 per ton.

Jan 1, 1998

By K. J. Hartman

The term kaolin is derived from "kauling". a Chinese word meaning high ridge, which was the name of a hill in China where kaolin was first mined several hundred years ago.(1) Other common names used today for kaolin include "clay" and "China Clay". The former word technically has a broader meaning and could refer to various types of clays such as bentonite and ball clay as well as kaolin. China clay, as a descriptive term, apparently results from kaolin's origin as described above but could also be due to a significant historical use in ceramic applications. The terms "kaolin" and "clay" will be used interchangeably in this analysis because of the common practice of using these terms in the paper industry. Major reasons for kaolin's widespread industrial usages center on the mineral's (kaolinite) physical features of good color, low viscosity and inertness. Kaolin is described as a hydrous aluminum silicate with approximate composition Of 2H20.A1203.2Si02. As will be shown later, a new version of the product, calcined clay with modified hydration content, is gaining widespread usages. Components of any particular kaolin in addition to alumina and silica are viewed as impurities. The more valued deposits and, hence, higher priced kaolin products are those of highest purity.

Jan 1, 1986

By Philip Antunes, A. E. (Tony) Reschke

"INTRODUCTION Tunnel Boring Machine (TBM) operations require the injection of material into the annular tail voids as the machine advances ahead of the segmental concrete lining. This annular gap is created because the cutting diameter of the TBM has to be larger than the outer diameter of the concrete segments of the tunnel lining. Fundamentally, the two basic types of annular grout are thick, concrete like mortars and thin, mobile, two-component grouts. While some European countries seem to still favor the concrete like mortars, from a global perspective it is now the two-component type grouts that dominate the industry. Two-component type grouts are comprised of an “A” component grout (typically cement, flyash, bentonite and a retarder/stabilizer) and a “B” component accelerator (sodium silicate or water glass as it is sometimes known). They are thus sometimes referred to as A/B type or bi-component grouts and were pioneered by the Japanese over 30 years ago. They offer a host of operational benefits over thick mortars, such as reduced settlement (Feddema et. al., 2001), effective penetration of the void space, with less energy, and reduced strain on the segmented linings (Robinson et. al., 2007). Two-component grouts are highly mobile and can be pumped many kilometers. The use of a retarder/stabilizer can also extend the shelf life of the “A” component grout for several days while the early strength of the accelerated grout stabilizes the ground and supports the segmental liner almost immediately. The batch plants that prepare the two-component grouts use one of two possible mixing methods for preparing the “A” component grout. The simplest plants use paddle type mixers and numerous tunnels worldwide have been successfully grouted using this technology. However, a superior type of mixer is available, namely the high shear colloidal mixer. Keller Colcrete successfully pioneered the development of the colloidal mixer back in 1937 and for over 75 years colloidal mixers have been internationally recognised as the most efficient method of mixing cement based grouts (Houlsby, 1990). These mixers are used in grout preparation for radioactive waste encapsulation, hydro dam grout curtains, soilcrete jet grouting, soil nailing, and numerous other geotechnical applications. In tunnelling, these mixers are also used for ground treatment, compensation grouting and for the preparation of bentonite lubrication for pipejacking. It has been only within the last decade however that these high-shear colloidal mixers have been adapted for use in the preparation of two-component grouts."

Jan 1, 2016