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By V. K. Gupta

A detailed experimental study of the variations in grinding rate with particle size, particle load, ball diameter, ball load, mill diameter, and mill speed was carried out for a soft cement clinker and a hard cement clinker. The effects of the ball diameter, ball load and particle load were observed to be material (hardness) independent, and those of the particle size, mill diameter and mill speed to be material dependent. A sharp change in the grinding behavior was observed for both the clinkers at about 150 µm size. Below this critical size: (i) the hardness difference between the two clinkers became insignificant, (ii) variation in the grinding rate with particle size became markedly more pronounced, and (iii) mill speed had little or no effect on grinding rate. The importance of these results in the context of process optimization and control is discussed.

Jan 1, 1987

By E. McCullough, S. Gaillard

"Diesel particulate matter (DPM) has been regulated by the U.S. Mine Safety and Health Administration since 2002 in underground metal and nonmetal mines. To demonstrate regulatory compliance, DPM samples must be collected and later analyzed by the U.S. National Institute for Occupational Safety and Health (NIOSH) 5040 standard method, but the FLIR Airtec DPM monitor can serve as a complementary engineering tool. The monitor is a handheld instrument that offers near-real-time measurements of elemental carbon (EC), which is a primary constituent of DPM. As part of an ongoing field study, the monitor was used to survey EC in an underground stone mine. This effort was aimed at determining spatial and temporal DPM variations in several key locations. The results of prolonged area monitoring—that is, lasting several hours — revealed that DPM concentrations were diluted substantially as air moved away from the primary production zone, but that concentrations could vary quite a bit in a single location from day to day and between seasons. DPM concentrations were generally lower in winter than in summer, which is consistent with increased natural ventilation airflows during winter. Using a modified sampling cassette, an attempt was also made to sensitize the Airtec monitor to allow for “spot-checking” of EC concentrations — that is, measurements made in several minutes. Preliminary field data showed that the sensitive cassette performed well in terms of providing accurate data that could be useful for rapid assessment of DPM. IntroductionDiesel particulate matter (DPM) is the solid fraction of the exhaust emissions from a diesel engine. It largely consists of elemental carbon (EC) and organic carbon (OC) (Birch, 2003). The World Health Organization International Agency for Research on Cancer classified diesel exhaust, including DPM, as a carcinogen (World Health Organization, 2012). It is believed to cause and/or exacerbate respiratory illness upon inhalation, deposition and retention in lung tissue. Because DPM exists in both the micro- and nanoparticulate ranges, it can bypass typical autoimmune defense mechanisms that keep larger particles out of the respiratory system (Ristovski et al., 2012)."

Dec 1, 2016

By S. Thibeault, P. Filiatreault, B. Straight, D. Castendyk, L. Cameron

"Unmanned aerial vehicles (UAV), or drones, capable of collecting and retrieving water samples from pit lakes, tailings ponds and other mine water basins will revolutionize environmental programs by lowering sampling costs and reducing safety related risks. Costs typically include a boat and associated equipment, boat transportation, road maintenance, water safety devices, water safety training, and additional staff. Typically, the total cost can exceed $20,000 USD per sampling event (excluding lab analyses). Hazards include potential for drowning, unstable pit walls, and unconsolidated sediment surrounding tailings ponds. Hatch has developed a novel device for aerial drones which currently enables the collection of water samples from depths up to 390 ft (119 m). This system only requires a pilot, a sample technician, and a safe operations point overlooking the water body. Hatch anticipates this will reduce monitoring cost by at least 50% while improving safety, reducing staffing requirements and accelerating data acquisition. This manuscript demonstrates profiling and sample collection from a 95 ft (29 m) deep reservoir and a 377 ft (115 m) deep pit lake, and highlights the potential of this emerging technology. INTRODUCTION Working on or near water at active, closed, or abandoned mine sites is inherently dangerous. Between 1996 and 1999, the United States Mine Safety and Health Administration (MSHA) reported 17 fatalities involving drowning at US metal, non-metal, and coal mines (MSHA, 2000). Open pit mines which fill with water following mine closure, called pit lakes, present numerous risks to environmental monitoring teams including drowning, hypothermia, falls to the ground from the top of high walls, and rock avalanches resulting from steep, unstable pit walls. Some pit lakes are simply not easily accessible for ongoing monitoring. However, the routine collection of water samples from the entire water column on at least an annual basis is required to monitor the evolution of water quality over time, to verify the accuracy of numerical predictions, and to manage lake water chemistry in order to produce “treatable” influent to water treatment plants, and ultimately, produce acceptable site discharge water quality. As a product of these risks and the need for water sample, mining companies spend considerable expense on pit lake safety as part of monitoring. This includes training personnel for “on water” duties and hazards, purchasing or hiring specialized equipment and personnel (such as boats, boat operators, personal floatation devices, and mustang suits), stabilizing pit walls and maintaining safe access roads to the lake surface, employing spotters with direct communication to emergency medical services to watch sampling activities (because cell phones and radio signals can be blocked by pit walls), and utilizing redundancy to prepare for unexpected incidents and accidents. For example, one Canadian mining company requires pit lake water samplers to hold Marine Emergency Duties (MED) training to ensure the entire boat crew is sufficient and competent for the safe operation of the vessel, and uses three boats for water sampling: two on the water at all times, and one on the shoreline, ready to deploy. The costs of these safety mechanisms greatly adds to the overall expense associated with pit lake sampling. Consequently, environmental programs may need to reduce the frequency of pit lake sampling in order to keep monitoring programs within an acceptable budget"

Jan 1, 2017

By Thomas F. Clemens

This paper covers various changes in government regulations, taxation, and legislation for the past two plus years and the up- coming one. Part of the paper will discuss recent business conditions and how they have affected the cement and lime industry.

Jan 1, 1983

By Robert E. Murray

The title of my paper, "A Company's Response to Federal Coal Leasing," brings to mind a picture of a dog chasing its tail. This is what the coal industry, has been doing since the Federal coal leasing moratorium went into effect in 1971. We've gone around in many circles, but we are only very slowly, if at all, getting closer to catching our tails, i.e., efficient, economical, and rational Federal coal leasing. My companies, The North American Coal Corporation and its four Subsidiaries, The Falkirk and Western Plains Mining Companies and The Coteau and Missouri Valley Properties Companies, together hold in excess of 4.5 billion tons of lignite reserves in North Dakota. Some of our North Dakota properties are substantially interspersed with Federal coal, with the government holding title to the minerals in every other section. This checkerboard pattern of Federal ownership has made it difficult to develop and market some of our reserves, and, as a result, it has become imperative that we be familiar with and active in the Federal Coal Leasing Program.

Jan 1, 1982

By William Gleason

While a fleet of 100 t (110 st) haul trucks were busy removing overburden from the open pit mine in the distance, a host of dignitaries, including congressmen and California state representatives, gathered for Molycorp?s official groundbreaking ceremony at the Mountain Pass Mine on April 20. The mine, recognized as arguably one of the richest rare earths deposits in the world, is at the center of Molycorps? strategic ?Mine to Magnets? plan. It aims to secure America?s future supply of rare-earth-dependent technologies by developing a strong domestic rare earth industry. Molycorp identifies rare-earth-dependent technologies as those that cannot be produced without rare earth materials. The list of these technologies is long and growing. It encompasses everything from personal electronics and batteries for hybrid cars to permanent magnet generator wind turbines and national defense applications.

Jan 1, 2011

By Ihsan Berk Tulu, Mark Alexander Van Dyke, Deniz Tuncay, Ted M. Klemetti

Bleeder entries are critically important to longwall mining for the moving of supplies, personnel, and the dilution of mine air contaminants. By design, these entries must stay open for many years for ventilation. Standing supports in moderate cover bleeder entries were observed, numerically modeled, and instrumented by researchers at the National Institute for Occupational Safety and Health (NIOSH). The measurements of the installed borehole pressure cells (BPCs), standing support load cells and convergence meters, and roof extensometers are presented in this paper in addition to the numerical modeling results and visual observations made by the NIOSH researchers in the bleeder entries. The results include the effects of multiple panels being extracted in close proximity to the instrumented site as well as over one and a half years of aging. As expected, standing supports closer to the longwall gob showed the greatest load and convergence. The roof sag appeared generally independent of the proximity to the longwall gob. The BPC readings were driven by both the proximity to the gob and the depth into the pillar. The results of this study demonstrated that the entry roof can respond independently of the pillar and standing support loading. In addition, the rear abutment stress experienced by this bleeder entry design was minimal. The closer the mine development, pillar, or supports are to the gob, the greater the applied load due to rear abutment stress.

Jan 7, 2021

By A. A. Wallach

During the early design stages of the San Manuel Concentrator, numerous questions were raised concerning the required slope for tailings pipelines. The tailings disposal area which had been selected was so situated, that an average down-slope of 5% existed. A gravity tailings disposal system was to be designed and it was necessary to determine the optimum pipeline slope for design purposes. This information was also necessary to determine the life of the available disposal areas before tailings pumping would be required. At approximately the same time as this problem arose, it was reported that a concentrator in the southwest was having considerable operational difficulties due to periodic plugging of tailings lines. These factors combined made it seem desirable to conduct some sort of test work which might give information concerning the flow characteristics of the tailings to be produced, from the San Manuel Concentrator. It was felt that the maximum information could be obtained if a tailings line could be erected which would allow for varying slopes, varying heads and accurate measurement of pulp velocity. A five-foot Denver Agitator was installed on a bank overlooking a cut for a rail- road track. Approximately 160 feet for new &-inch pipeline with victaulic connections was installed on low trestles along the track, with provisions made for varying the slope of the line by use of accurately constructed sets of shims, A valve discharge was installed on the tank so agitated pulp could be run into a standpipe at controlled volumes. This standpipe was 10 inches in diameter and approximately 5 feet high. A 4-inch nipple welded into the side of the standpipe approximately one inch from the bottom was connected to the 4-inch pipeline. At the discharge end of the 4-inch pipeline a launder arrangement was so constructed that the entire discharge could run into a pump sump or into 50-gallon measuring vessels. In normal operation the flow was from the agitator to the standpipe through the pipeline into the pump sump and from there pumped back to the agitator tank.

Jan 1, 1958

By Michael MacMillan

The mining industry has always operated under intense public scrutiny. Community expectations, investor pressures, regulatory obligations, and environmental oversight create a uniquely complex communications environment. In recent years, technological change, climate urgency, and geopolitics have reshaped how the industry communicates its role and value. The rise of artificial intelligence in the information ecosystem represents yet another fundamental shift. As AI evolves, an organization’s reputation will no longer be shaped solely through human interactions, media coverage, social activity, or corporate disclosure. Increasingly, public understanding depends on how AI systems interpret and represent company information. These systems influence search results, conversational tools, news aggregation, social discourse, and even investor intelligence platforms. As AI-generated summaries, answers, and narratives become the default interface for stakeholders, they also become authoritative in shaping trust. For mining companies, this creates both risk and opportunity. The organizations that recognize how AI reads, prioritizes, and amplifies information will be better positioned to build trust. Those that remain silent or rely on traditional communication methods may find their reputations being algorithmically defined without their participation. This paper explores how mining companies can proactively engineer their reputations in the age of AI.

Jan 1, 2026

By Dwight K. Smith

Fly ash as an additive for oil well cement was introduced to the oil industry by the Halliburton Company in 1949. Since its early usage in the Illinois area of the U. S., the total amount of fly ash pumped into wells has exceeded 30 million sacks, The advantages of using fly ash-portland cement mixtures in wells are fundamentally the same as for concrete except the conditions of placement and curing are variable and the nomenclature of properties are expressed somewhat differently. In some instances deep wells have been cemented with mixtures of fly ash and hydrated lime together with an activator which functions as a catalyst for setting. This fly ash-lime formula has many advantages for high temperature-pressure conditions found in wells.

Jan 1, 1968

By Justin Carl, Aliuddin Mohammad, Gordon Evans, Steven Bealby, Carlton Ray

"The District of Columbia Water and Sewer Authority (DC Water) is implementing the $2.2-billion DC Clean Rivers Project (DCCR) to control combined sewer overflows (CSO) to the Anacostia and Potomac rivers and Rock Creek, and to provide flood relief to the Bloomingdale and LeDroit Park neighborhoods in the District of Columbia. The long-term control plan complies with the requirements of a Federal Consent Decree entered into by DC Water, the District of Columbia and the United States, as represented by the U.S. Environmental Protection Agency and the Department of Justice. The Northeast Boundary Tunnel, a design-build project, will store combined sewage and deliver it to a system of downstream tunnels and ultimately to the Blue Plains Advanced Wastewater Treatment Plant (Blue Plains), where it will be treated. In addition, the Northeast Boundary Tunnel (NEBT) is a major project associated with the mayor’s task force to alleviate extreme flood events in Bloomingdale and LeDroit Park. The Northeast Boundary Tunnel Utility Relocations (NEBTUR) design-bid-build (DBB) project is an accelerated component of the Anacostia River System, as shown in Fig. 1. During dry weather conditions, the entirety of the sewage in the combined system is conveyed to Blue Plains.During storm events, when sewer pipe capacity is exceeded, the flow, which is a mixture of sewage and stormwater runoff, overflows into receiving waters through outfalls. There are a total of 47 active CSO outfalls along district waterways.The influx of storm runoff into the combined sewer has an additional impact on the communities of Bloomingdale and LeDroit Park. The sewer system is outdated and undersized. In these neighborhoods, when the capacity of the sewer is exceeded, localized flooding occurs and backups into adjacent residences are prevalent. In any given year, there is a 50-percent chance that flooding will occur in these neighborhoods."

Jan 9, 2017

By P. A. Hendricks

The surface coal mining industry in the United States employs over 50,000 people and is responsible for 60% of domestic coal production. This represents a very significant contribution to our national economy and an important source of highly skilled and well paying jobs. The U.S. Bureau of Mines (USBM) has targeted surface mining as an important research priority to reduce the social and economic costs associated with surface mining injuries and fatalities. USBM safety research focuses on the development of technologies that can enhance productivity and reduce mining costs through a reduction in the number and severity of mining accidents. This report summarizes a number of completed and ongoing research programs that address a broad range of surface mining safety problems. Research methods are described, and research products which are suitable for industry implementation are highlighted.

Jan 1, 1994

By H. Maleki

This paper recognizes the 100th year of research accomplishments by the mining industry resulting from close cooperation among mining companies, geotechnical consultants and researchers from the former United States Bureau of Mines in stability assessments and development of improved and productive mine designs. The paper provides an overview of dramatic developments in geotechnical instrumentation, and its applications in the U.S. and around the world for enhancing the understanding of ground response to mining-induced changes in stress, resulting in improvements in ground control technologies.

Jan 1, 2010

By Y. C. Kim

The strongly skewed grade distributions and the need to estimate the local recoverable reserves in a selective mining environment are the two problems that Ordinary Kriging (OK) cannot easily handle. With the recent introduction of the nonparametric, distribution-free technique of Indicator Kriging (IK), the above problems can be solved. This paper describes the results of performance evaluation of IK in an open-pit gold-silver deposit. For performance evaluation, the predictions of local recoverable reserves using IK were compared with the actual reserves based on blast hole information. The IK estimator, although a bit optimistic, performed very well in predicting the total recoverable ounces of gold from each panel on a test bench. The OK estimator was also used to try to predict local recoverable reserves, by treating each panel as either waste or ore, depending on the panel's average grade. Under this criterion. OK was found to be very biased and pessimistic.

Jan 1, 1986

By Alessandro Navarra, Aldo Quelopana

For decades, open-pit mine planning algorithms have incorporated geological uncertainty and other elements or characteristics for increasingly realistic representations. Among these complexities is the detailing of downstream processes that occur inside processing plants. Previous studies have demonstrated that the strategic mine plan and mineral concentrator design are coupled, and should therefore be optimized simultaneously within the same quantitative framework. However, existing frameworks offer limited representation of operational modes. This work demonstrates an approach to resolving this gap, in an optimization based on a parallelized Variable Neighborhood Descent (VND). The resulting algorithm embeds mass-balancing linear programming (LP) using a DantzigWolfe decomposition. A case study of a Zn-Pb deposit is presented to show the performance reached.

Jun 25, 2023

By R. E. Cook

"Mineral deposits require substantial amounts of energy to transport and be processed into usable form and, as such, present a real processing challenge in that the deposits are never homogeneous and orebody compositional characteristics are all over the map. Extracting the desired mineral(s) from the deposit at sufficient profit margin, despite severe fluctuations in market price, requires process automation architecture capable of supporting an integrated enterprise solution. Such an architecture will encompasses the activities of individuals, process units, process areas, plant level activities, mine management and business planning, and accounting systems. Key to the automation process is the aspect of value generation. This article brings together the various requirements for the automation of a mining enterprise and presents the different aspects of how to obtain value across the entire mining operation.Minerals’ processing sites are historically long lived, with 20-year life-of-mine not uncommon and 75 years not unheard of. Considering that hardware technology advancements are introduced every six months, or less, it is prudent to select process automation systems that adhere to “open” industrial standards versus proprietary based systems. In the minerals processing industry, the key to survival is driving the cost of production per unit volume to the lowest possible level and provide enough profit to sustain operations. Control system architecture and business information technology are rapidly becoming important tools in the quest for productivity. Getting key dynamic business performance information at the right time to the right person or process unit is crucial to successfully achieving corporate goals. The process automation architecture selected must, therefore, be able to integrate to the various networking enterprises and business systems.The mining industry is generally known as an extractive industry that is physically oriented with respect to operations and the activities in which workers engage. Large numbers of people performing manual tasks in difficult surroundings, produce variable outputs. But times are changing – and so are industry best practices. While the nature of work still consists of activities such as ore extraction, ore movement, ore concentration, refinement and logistics, automation innovations are starting to change the nature of many of the production steps. The industry has transitioned from requiring more physical activities by workers to more information management, automated control and collaboration within the operation. Humans are good at situational intervention and nonlinear reasoning and do best when empowered with an overall production perspective. Machines and automation are good at repetitive functions, steady state operation, and managing transitions. Thus, a combination of advanced technology solutions, reliable and useful information and full human contributions are necessary to mining operations for value generation."

Jan 1, 2015

By Kexin Cai, Isidro Rivera, Shawna Von Stockhausen, Maria Chastka, Kevin Huynh

The Newell Creek Dam Inlet/Outlet Replacement Project is located approximately 11 miles north of Santa Cruz, California along Highway 9 in the San Lorenzo Valley. This project will replace the existing inlet/outlet works at the Loch Lomond Reservoir by constructing a tunnel using conventional excavation methods while simultaneously drilling three intake shafts to intercept the tunnel from within the city’s water supply. This project will improve the system’s overall operational efficiency and performance, and provide a safe and reliable facility for the City of Santa Cruz’s drinking water supply. This paper discusses the overall project configuration, construction observations, and challenges during construction, including tunnel excavating through the marine sedimentary siltstone of the Monterey Formation, probing and pre-excavation grouting, and the tools utilized to manage the project.

Dec 1, 2022

By Eileen Ashworth

Computer-assisted instruct ion is now being used in areas as diversified as training handicapped children to preflight simulation for airline pilots. This paper reports on two courses that have been developed at SDSM&T on the PLATO system for miner safety training. Advantages of computer-assisted instruct ion for this type of training is discussed. (Figures show examples of actual use.) A discussion will be given on other applications such as maintenance troubleshooting, training of engineers and managers at remote sites and training of local people for working in the mine.

Jan 1, 1983

By J. J. Kollé

A compressed-water hydraulic pulse generator (HPG) for nonexplosive blasting of rock and con¬crete is described Energy is stored in the HPG by compressing water to ultrahigh pressure. A large, fastopening valve discharges the com¬pressed water, resulting in a high-energy impulse. The HPG can be used for small-scale bench blasting by discharging the water through a nozzle that is closely fitted into a borehole. A bench blasting system requires an HPG, a drill and an indexing mechanism to allow insertion of the HPG nozzle into a drilled borehole. Systems with discharge energies ranging from 40 to 250 kJ have been used to excavate hard rock, including andesite, granite and quartzite. The largest system can excavate 15 t/h (16.5 stph) of massive quartzite based on a 2-min cycle time for hole drilling. Blasting with an ultrahigh-pressure hydraulic pulse generator was demonstrated as an effective means of excavating hard massive rock under the confined conditions of a tunnel opening or underground sloping panel. Hydraulic blasting provides a continuous mechanized mining capability that is well suited for deep-level mining and urban excavation sites where explosives are prohibited

Jan 1, 1997

By Wei Victor Liu, Na Zhang, Chengkai Fan, Bei Jiang

This study used artificial neural networks (ANNs) coupled with Gaussian mixture modeling (GMM) to analyze truck haulage data from openpit mines. The proposed weighted ensemble models performed better than benchmark models in predicting truck productivity, providing a new means of solving complex data and improving mine planning and decision-making.

Jun 1, 2023