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By R. K. Singhal

A variety of mining equipment is used in the mining of oil sands by surface mining. This includes bucket wheel excavators, draglines, hydraulic shovels and off-highway trucks. This paper examines the existing mining schemes and equipment used Peculiarities of oil sands surface mining and their influence on equipment selection, utilization and mining schemes are described. Recent developments undertaken to improve mine productivity are also dealt with together with some notes on proposed measures to obtain further gains in productivity.

Jan 1, 1985

By D. U. Gustafsson

After half a million meters drilled with Wassara we are now confident that ITH hammers powered with simple water will become an established product for production drilling. Today four drill rigs in LKAB Malmberget equipped with Wassara drill about 25 000 m per month of 4 1/2" holes. In Kidd Creek, Canada, Was sara is used for production drilling in stopes with good results. The first Wassara 6" hammer has drilled a 36 meter long, completely straight horizontal cut hole for drifting in the LKAB Malmberget Mine. Main advantages are about doubled penetration rate, very good air quality and improved hole cleaning which facilitates stabilized drilling. Disadvantages are resistance to new technology and, in some cases, the increased use of water.

Jan 1, 1995

By John F. M. Sims

Political issues and a glaring infrastructure deficiency have retarded the emergence of a strong mining component to the Alaskan economy in recent years. Barriers to orderly mineral development are slowly being removed attendant upon changing political circumstances. Infrastructure development, as an investment avenue as well as a responsibility of the State, is receiving much greater attention than in the past. Alaska of course has a rich and varied mining history going back to the 19th Century. This paper, however, focuses on the mining potential, not the mining heritage of the 49th State. The mining industry is emerging from a nadir in the economic cycle - times during which it was buffeted by unsympathetic administrations and confused and confounded by the protracted land status- conflicts prior to enactment; of the Alaska National Interest Lands Conservation Act (ANILCA) and other milestone legislation. Today Alaska's mining industry looks toward a bright and healthy future and, in the process, will become a very important and vital component of the State and national economy.

Jan 1, 1982

By L. John Minnick

Extraction of crude ores and minerals inevitably produces various by-products either as a result of nonusable residues or as waste by-products from process operations. Thus for each 100 tons of coal extracted in a strip mine operation, one can expect to produce 25 tons, or more, of mine refuse. In addition, the amount of ash produced from the burning of coal will represent 10 to 20 percent of the weight of coal burned. With the advent of lime/limestone scrubbers now being installed on many power plants, an additional by-product is produced that in most instances is equal in volume to the sluiced fly ash. Statistics developed by the National Ash Association have indicated that sluiced waste from power plants in the United States currently exceeds 25 million tons per year (dry basis). Overall mineral industry statistics (copper mines, etc.) indicate better than 200 million tons per year. In the past it was general practice to send most of these waste materials to holding ponds or lagoons simply as a means of disposal or "throwaway" of unwanted by-products. Unfortunately modern society has reached a stage where these large quantities of waste materials are creating monumental environmental and economic problems that need urgent attention. Among these problems are concern for loss of future usable land, pollution of ground water, loss of potential mineral reserves, and loss of opportunities to recycle or use these by-products for the benefit of future generations. An example of the latter is the serious shortages of construction quality aggregates that can be replaced with some of the by-products produced from waste materials from the extractive and chemical industries.

Jan 1, 1975

By MOHAMMED AMINE BELMI, ANAS DRIOUCH, ABDELAZIZ LAHMILI, LATIFA OUADIF

The mineral industry uses significant amounts of water in processing. Thus, sustainable practices with the processing of ores are of critical importance. An impact tester was used to measure the adhesion force between particles and a glass disk [1,2]. A removal force was caused by the impact of the disk/particle containing a puck with a stopper. Johnson-Kendall-Roberts (JKR) theory [3] was used to determine the interfacial energy between the particles and the substrate. Capillary condensation of water can occur between the particle and surfaces in humid environments. The adhesion of particles on rough surfaces has been studied previously [4-10]. The research presented herein combines both variables to separate particle types with minimal water usage.

By S. K. MONDAL, K. K. K. SINGH, S. Singh, R. K. TIWARY, S. K. Chaulya, G. C. MONDAL, R. S. Singh, T. B. SINGH

In this work, a comprehensive field study was carried out to measure the background air quality status and identify the air pollution sources from opencast mines around a heritage site in India. Air quality modeling was conducted to envisage dust concentration due to existing and closed mines in the region. The air quality modeling exercise predicted that particulate-matter levels of PM10 and PM2.5 might increase in the ranges of 3.2 to 23.1 and 2.1 to 8.9 μg/m3, respectively, due to mining activities when some of the closed mines will be operated in the region without controlled emission. The predicted total PM10 and PM2.5 at the selected receptor locations were in the ranges of 86.39 to 194.89 and 34.82 to 99.55 μg/m3, respectively. Adequate measures were suggested to control air pollution from mining activities, and an intelligent dry fog system was designed to suppress dust emission efficiently from mineral processing plants and opencast mines. The developed system has special features for facilitating eco-friendly mining.

By Brendan Demich, Brendan Macdonald, Timothy J. Orr, Jason Navoyski, Jennica L. Bellanca, William J. Helfrich

Recent advances in computing, rendering and display technologies have generated increased accessibility to virtual reality. Virtual reality allows for the creation of dynamic, high-fidelity environments to simulate dangerous situations and test conditions and to visualize concepts. Consequently, numerous products have been developed, but many of these are limited in scope. Therefore, U.S. National Institute for Occupational Safety and Health (NIOSH) researchers developed a virtual-reality framework, called VR Mine, to rapidly create an underground mine for human data collection, simulation, visualization and training. This paper describes the features of VR Mine, including mine generation, simulated networks, proximity detection systems, and the integration and visualization of real-time ventilation models.

In subterranean mining operations, access to communication networks deep underground is critical for transporting data, voice and video, and other supporting applications that are essential for efficient and safe operations. Whether accessing sophisticated ERP or maintenance management systems, engaging in fleet management, video surveillance, or access control, or protecting miners with wireless locator systems, these networks serve as a literal lifeline between workers deep within mines and surface operations. For this, mining networks require more than permanently installed network cabling, it also requires unique deployable systems designed for quick installation, extension and even relocation as the active mine site area moves, or equipment is moved in and out.

Mar 1, 2014

By G. V. R. Landman

In order to obtain a better understanding of the explosion risk at the coal face, anomalies in the ignition sensitivity for different modes of ignition of hybrid mixtures of dust, methane and air were studied. Results indicated that the explosible behaviour of the working environment is highly dependent upon the ignition source and the fuel composition. For example, depending on the ignition source, the same hybrid mixture can be inert or extremely explosible. In conclusion, it is stressed how the explosion risk can be expressed in terms of a safety factor which takes into account the influence of both the fuel and the ignition source.

Jan 1, 1994

By R. A. Winters

At the operations level, productivity is a principle key to profitability. If you are competing with other mines that are paying roughly the same wage rate and the same prices for capital, materials, and energy, the only way your profit can be greater is by producing more output per unit of input. Mines with higher productivity have higher profit margins. Higher profit margins lead to greater operating cash flow, and cash flow is what distinguishes a dog from a cash cow. The turnaround in U.S. metals during the 1980s was in large part due to incredible improvements in productivity. According to statistics compiled by Kaufmann, 1991, labor productivity, measured as tonnes of primary production/manhour, increased 64% in steel, 94% in copper, 75% in lead, 143% in zinc, 132% in molybdenum, and 75% in gold. These improvements were hard won. However, with most modernization programs now complete, measuring and monitoring productivity becomes even more important as producers strive to maintain the gains they have achieved.

Jan 1, 1993

By Ivan V. Klumpar

If components of a gas-liquid stream react with each other and with stationary solids, involving parallel and sequential, reversible and irreversible, and slow and instantaneous reactions, the process can be defined by a set of simultaneous differential rate equations and simulated as multistage semibatch re¬actors. Each stage is divided into finite time increments. Within each increment, even the simultaneous reactions are treated as sequential. The proposed method follows process evolution from non-steady state startup to normal operating conditions. It allows computing byproduct buildup in recycles, tracer response curves and, in case of underground processes, expansion to adjacent parts of the deposit.

Jan 1, 1979

By Richard Newcomb, Michael Rieber, William A. Vogely

INTRODUCTION The solid fossil and nuclear fuels, but especially uranium, are given prominent, indeed leading, roles by energy experts in most long range estimates of world energy futures. Optimistic forecasts are inspired partly by the disproportionately large solid fuels resource base compared to present rates of consumption or to oil and gas resources, and partly by the vision of inexpensive high technology applications. Such a view overlooks the fact that while resource- use disparities and new technologies give allure to the promise of the solid fuels, they do not guarantee cheap solutions to the basic problems of solid fuel uses: viz., their relatively difficult conditions for efficient ignition and control, including the management of environmentally acceptable residuals disposal. Contrary to the varied versions of this optimistic hypothesis, this paper shows that a great many persistent economic and technical problems interfere with such a simple inference. These act as constraints which qualify or dispute much of the national energy policy based on existing modeling of solid fuel requirements and optimistic engineering evaluations. The assumptions and techniques of such exercises are sometimes at fault. As often as not, however, the distortions created in open market fuel com- petition due to misdirected national energy policies themselves are to blame for misdirected efforts. A number of interesting implications result. Among them are the distinct possibility that the low technology applications will dominate, so that more direct coal and less synfuel or nuclear use will occur; that, accordingly, exhaustion rates for uranium will be low, that the most extensive growth of solid fuel through 2000 will be in conventional pulverized coal cumbustors, and that the traded share of the world coal bum will be much larger than predicted. These trends will place much more pressure on oil and gas prices than forecast by most experts. On the way to these findings the paper demonstrates that solid fuel resource adequacy in situ, balanced against the projections of demands as capacity requirements, mean little as conventionally measured by years to exhaustion or potential supply schedules. Indeed, all stock concepts of demand requirements or of fuel re- sources must be tied to the paths of the unit costs and the deliverable prices of all substitute fuels and systems over time. This requires a dynamic analysis of supply and demand, integrated with geological and engineering constraints, to provide insights into the multiple modes of market and product substitution. Market forces rather than technical promise will determine the allocation of the solid fuels. Moreover, the equilibrium paths of individual fuel prices and market shares are not easily simulated by general or network models, and decision makers will continue to rely on the partial, local comparison of alternatives in their choices of fuel systems at any time. 'The economics of the solid fuels differs from that of other energy sources in important ways relating to their form in use, conversion efficiency, (dis)economies and externalities. Petroleum and gas are in a more convenient form for

Jan 1, 1985

By YONGQIONG YANG, Ning Wang, CHONGGUANG LUO, LI ZHU, Hanjie Wen, SHENGJIANG DU, Hannian Gu

Kaolin clay from Late Permian sequences has been considered a potential resource for niobium (Nb) due to high concentrations reported at several hundred micrograms per gram and large areal distribution. A previous case study identified titanium (Ti)-bearing minerals associated with kaolin clay as the main host phases for niobium. Correlation between the Nb and Ti concentrations was poor, however, and the types of Ti-bearing minerals and modes of Nb occurrence were unclear. To investigate this, typical kaolin clay samples from Late Permian sequences in southwest China were characterized, and final products derived from them were investigated using X-ray fluorescence (XRF), inductively coupled plasma-mass spectrometry (ICP-MS), X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy-dispersive X-ray spectroscopy (EDS). The results revealed three types of titanium dioxide (TiO2) mineral phases in the clay samples: (1) massive TiO2 minerals, (2) aggregates of nano TiO2 minerals and (3) granular TiO2 minerals. The first two did not contain niobium. From the EDS analysis, the granular TiO2 minerals, including anatase and rutile, were the source of Nb in the kaolin clay samples. 

By Leo Gentile, David Selhorst

The $528 million Toledo Waterways Initiative (TWI) was implemented by the City of Toledo in 2002 and completed in August 2020. Toledo is one of many US cities required to implement a Long-Term Control Plan (LTCP) but one of few to have completed its plan. TWI consists of three storage and conveyance tunnels, four below grade storage basins ranging from 4 to 36 million gallons (MG), miles of sewer separation and interceptor improvements, green infrastructure and other appurtenant structures to dramatically reduce combined sewer overflows to the Maumee River, Ottawa River and Swan Creek. All three rivers flow into Lake Erie. The City’s 180-year history as a Midwest shipping, manufacturing and transportation hub provided design engineers and contractors no shortage of unknown underground challenges to complete the projects. The City will begin its 5-year Post-Construction Compliance Monitoring in 2021 to satisfy the final LTCP requirement. A program overview and experience from tunnel and underground basin construction in urban areas with buried active and legacy infrastructure will be discussed.

Jun 13, 2021

By D. A. Bird

Geochemical models using published thermo-dynamic data and laboratory derived kinetic rate laws allow prediction of post-closure pit lake geochemistry at open pit mining sites. A combination of "forward" and "inverse" modeling techniques can predict the pit lake geochemical evolution from initial infilling to eventual steady state attained decades or centuries after closure. Computer codes have been developed to model chemical reactions such as pyrite dissolution, describe the ground-water flow regime, and provide rock-water ratios. The incorporation of site specific information, such as ultimate pit dimensions, geologic and hydrologic data, acid generating potential (AGP) vs. acid neutralizing potential (ANP), and laboratory derived kinetic rates, allows application of the model to open pit mines at any stage of development.

Jan 1, 1994

By Jamal Rostami, Tom Iseley, Saleh Behbahani

Tunnels and underground infrastructures assets, like all assets, deteriorate with time. At some point, they reach the end of their useful life. Therefore, frequent inspections, higher levels of maintenance, and rehabilitation are needed to address loss of life and safety concerns. The repair cost of tunnels will increase if maintenance of tunnels is not satisfactory and timely. Historically, tunnel inspections have primarily relied on visual and manual procedures. Due to their time-consuming nature and susceptibility to human error, there is a demand for alternative automated techniques that can enhance efficiency and reliability in tunnel inspection. By utilizing a tunnel scanning system, such as laser scanner and thermography, or photogrammetry system, tunnel inspection cost, time, and personnel can be reduced. The goal of this study is to utilize deep convolutional neural networks (CNNs) for automated identification of defects in tunnel lining inspection. This paper presents a framework to classify two types of defects in tunnel lining (water leakages and cracks) using CNNs. The CNNs were trained and tested using 4,608 images. The Precision, Recall, and F1 Score were each 99.6%, confirming the viability of this approach in the automated defect identification in tunnel lining.

Jun 23, 2024

By Diler Katircioglu-Bayel

This study aims to investigate the effect of combined mechanical and ultrasonic milling on the size reduction of talc. First, the talc sample was wet-ground in a stirred media mill for five different lengths of time (30, 60, 90, 120 and 150 min), and the optimum result was subsequently achieved with treatment by ultrasonication. The effects of amplitude (20, 35 and 50 µm), solid ratio (2.5, 5, 7.5 and 10 percent), and sonication time (60, 120 and 240 min) on the sizes of the final product were investigated. The pre-milling by wet grinding caused a decrease in the grinding resistance of talc. Sequential ultrasonic treatment, which was applied to the talc sample, generated smaller particles in comparison to those acquired by stirred media milling alone. Experimental results were assessed based on the product particle size (d10, d50 ), reduction ratio and specific energy consumption. Submicron particles prepared by ultrasonic treatment were highly stable compared to stirred media milling alone as investigated in terms of particle size. In addition, the effects of mechanical and ultrasonic milling on the structural properties of talc particles were characterized by X-ray diffraction (XRD) analysis.

By E. McCarthy

"INTRODUCTION Talc is a hydrous magnesium silicate with the approximate elemental composition 4MgO.3SiO2.H2O. It is one of the layered phyllosilicates (like kaolin and mica) but it differs from these in that it is relatively hydrophobic. This is due to its unique crystalline structure whereby a brucite inner layer is sandwiched between silica layers and the adjacent silica layers have no interlayer bonding other than van der Waals forces. This allows talc to be sheared easily along this basal plane, and the surface is covalent not ionic. Talc occurs both as a relatively pure material (>90% talc content) and in conjunction with many other minerals in proportions all the way from 1% to 90%. At lower concentrations, it is often considered a nuisance mineral when it occurs with base metals like copper, molybdenum or nickel or with precious metals like platinum or palladium. It floats readily with these materials and often is suppressed using guar gum or carboxy methyl cellulose which will absorb along the basal surface and make it hydrophilic. Alternately if the reduced ore is hydrophobic, like MoS2, then a partial oxidation of the sulfide will convert the surface to a hydrophilic oxide and the talc can be floated away in a separate step. Talc in grades from 20 to 90% has been commercially exploited in a wide range of pigment (paint and paper), material (ceramic, construction and cosmetic), reinforcing (polymers and composites) and functional (pitch adsorbent, lubricating agent) applications. Initially these tended to be local or regional markets, but eventually with certain higher purity grades, cosmetic, polymer and ceramic applications became valuable enough to be national and trans ocean markets. TALC FLOATATION PLANTS This drove the need for higher purity grades of talc and initially this need was met primarily by ore sorting. This works well for certain deposits with well crystallized talc lenses, but for ores, such as those from widely available ultramafic deposits, where the liberation size is closer to 100 microns, sorting is not effective. That drove the need for floatation and the first investigations were published by Clemmer and Cooke of the US Bureau of Mines in 19362. The first commercial floatation plant was installed in Johnson, VT by the Eastern Magnesia Talc Co in 1937. The circuit is shown in the schematic (Figure 1). The ore was an ultramafic, serpentine derived talc; mineralogy was about 55% talc, 40% ferroan magnesite and 5% oxides, sulfides and other silicates. The oxides include hematite and chromite, sulfides pyrite and gerstorffite and silicates chlorite, serpentine and mica. After crushing, the ore was dry ball milled and then air classified to remove minus 325 mesh fines. The coarse fraction was further classified to cut at about 100 mesh and the fines from this were the feed to floatation. The -325 mesh (about 15% of the ore) was sold as a paint grade and the plus 100 mesh (about 25% of the ore) was screened to make an asphalt backsurfacing grade."

Jan 1, 2018

By Raj K. Rajamani, Samira Rashidi

Wear is an extremely important topic when considering high-pressure grinding rolls (HPGR) for any new application. Given the inevitable variations in ore properties throughout a mine’s life, it is difficult to predict the effect of material and operating conditions on the wear parts: specifically, the HPGR rolls. However, the possibility of continuous scanning of rolls provides ample information to review the wear pattern and ways to optimize it. In this regard, as part of a broader investigation, the feasibility of in-line scanning of HPGR rolls in a laboratory-scale HPGR is studied and presented. The choice of scanners and methods adopted to achieve high-level accuracy for determining wear is discussed in this paper, and the inherent variability affecting the measurements is evaluated. 

By JURGEN KRETSCHMANN

The European climate and energy framework for 2030 is highlighting the reduction of man-made CO2 by increasing the use of renewable energy. In this spirit, Germany has decided to erase coal use as an energy source by 2038 completely. This strategy premises a feasible, responsible and sustainable post-mining management. The Research Institute for Post-Mining (FZN) at the TH Georg Agricola University in Bochum, Germany, has developed a holistic approach to meet post-mining challenges. In all efforts, the FZN aims to achieve the fundamental goals of the United Nations to deal with the resources of our planet responsibly and sustainably.