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By Gilbert C. Robinson

Manufacturers of brick and tile are showing growing interest in the possibility of manufacture of a clay bonded block. The block would have the shape of concrete block, but would be made without the use of Portland cement, Instead, the block would be made' from mixtures' of an aggregate and the present raw materials of the brick industry. The finished units would weigh 20 to 30 pounds and meet the specifications for Grade A concrete block. The present status of the clay block development shows one manufacturer actually in production of these units$, two additional manufacturers are attempting production and many manufacturers are actively engaged in development work. At least four major research laboratories are engaged in the development program. There are several different processes available for clay block production. These processes differ primarily in the type of aggregate used or in the type of forming operation selected. I would like summarize these possible methods.

Jan 1, 1960

By R. Pazhianur

Cathodic Protection using impressed current was employed to reduce the wear of the mill wall during ball mill grinding. Wear rates were determined from weight-loss measurements made on four, I-inch diameter, mild steel coupons installed flush with the interior surface of the mill wall. Grinding tests were conducted on quartz, pyrite and quartz-pyrite mixtures at pH values of 4.6, 7.1 and 9.2. Cathodic protection was shown to reduce mill wear by 40-60010. An examination of the coupon surfaces using scanning electron microscopy showed that cathodic protection greatly reduced pitting corrosion. The presence of a sulfide mineral, such as pyrite, was found to increase the wear rate significantly, possibly due to galvanic interactions. It is also found that the wear rate is significantly higher than the sum of abrasive wear and the corrosive wear, due to a synergistic effect.

Jan 1, 1996

By G. Barbery

In Mineral Processing, the objective of most processes is the separation of mixtures of minerals, which are originally associated in composite particles. Feed preparation processes grinding for instance, which take place before beneficiation or separation processes do not usually break particles at the boundary between mineral phases. They produce composite ("middlings") as well as liberated particle. It is therefore necessary, in a particulate system, to determine the proportion of particles which are liberated as well as, ideally, the size distribution of minerals which remain associated in composite particles. Up to now, there has been a lack of experimental techniques to characterize completely composite particulate systems. Heavy liquid separation which is commonly used to obtain information of this type can only be applied to simple binary cases for which one mineral has a low density (lower than e.g 2.8 ). The technique which is proposed in this paper involves the measurement of parameters on polished sections of particles mounted in a matrix, and the use of mathematical transformations to reconstruct in three-dimensions the information obtained from these measurements .

Jan 1, 1977

By T. M. Needham

Increasing ore hardness led to a gradual reduction of mill throughput rates. This, combined with declining head grades and low gold price, prompted a review of milling practice at Kidston. Plant trials and computer simulation of the grinding circuit indicated the potential to increase mill throughput by up to 451 by reducing SAG mill feed size. Secondary crushing and additional ball milling capacity were installed. Commissioning was carried out successfully in September/October 1992. Design, operation and problems of the expanded circuit are discussed, and recent operating results are presented.

Jan 1, 1994

By D. Scott Scovira, Thomas Gustavsson

Exiting WW2, the potential of nitrates and hydrogen peroxide for application as industrial explosives both became known. The technology stream advanced the development and uptake of nitrate-based explosives to the point that they are the current global standard for blasting. Recently environmental issues are influencing the strategic agenda of extractive industries. The mid-2010s saw renewed interest in hydrogen peroxide explosives to eliminate NOx fume. Carbon reduction initiatives in the 2020s provided additional impetus to investigate hydrogen peroxide-based explosives. Hypex Bio is at the forefront of developing and delivering bulk gas sensitized Hydrogen Peroxide Emulsion (HPE) for blasting. HPE consists of hydrogen peroxide along with smaller amounts of fuel and emulsifier. The consistency of HPE is similar to industry- standard nitrate-based emulsions. It is compatible with existing priming and initiation systems. HPE does not contain nitrates and thereby does not produce post blast nitrous oxide fumes nor discharge of nitrates or ammonia to mine water. Importantly, HPE contributes to reduction in total carbon emissions as compared to nitrate-based explosives.

Feb 1, 2025

By W. Bosmans

The European Commission published its Communication of the Thematic Strategy on the sustainable use of natural resources ("Resource Strategy") on 21 December 2005. The Resource Strategy aims at reducing environmental impacts associated with resource use - called decoupling - in a growing European economy and worldwide. The impacts of unsustainable resource use include e.g. climate change due to fossil fuel use, land use and environmental degradation due to mineral extraction and processing, or overexploitation of soil and fish stocks. To decouple environmental impacts from economic growth, a life-cycle approach is adopted. It means that the environmental impacts are taking into account at each stage of the life cycle of a resource, avoiding that negative impacts are shifted to other environmental media, to other stages of the life cycle, or to other countries. Key to achieving decoupling are three factors: - More value - creating more value while using fewer resources (?resource productivity?); - Less impact - reducing overall environmental impact per unit of resources used (through ?cleaner? technologies and consumption pat-terns); - Better alternatives - substituting currently used resources with better alternatives. The paper focuses on the implementation actions of the Resource Strategy in particular related to the minerals industry: 1. The Data Centre on natural resources; 2. Indicators to measure progress; 3. The involvement of economic sectors to take concrete actions; 4. EU Member States involvement, focusing on resource uses with the most significant impacts; 5. The International Panel on the sustainable use of natural resources, set up together with UNEP. With its 25 years time horizon and its wide approach the Resource Strategy will have a co-ordinating function to ensure enhanced coherence and efficiency. The challenge will be to integrate this approach into all policies and decision-making.

Jan 1, 2007

By George J. Skoronski

The economics of pellet plant operation, in terms of fuel and power consumption, flexibility in the selection of the cheapest fuel source, system availability, maintenance costs, and the simplicity of process design, contribute to the determination of building and profitably operating a pellet plant. Design innovations, sup- ported by actual field data, have been initiated into the GRATE-KILN System design to positively address these factors. This paper presents the recent state of the art design concepts which have helped the GRATE- KILN System assume worldwide acceptance status.

Jan 1, 1983

By Gilmore R. Tostengard

The advent of inexpensive computers has opened vast opportunities for improved planning and control of capital projects. The mining and mineral processing industries have welcomed the opportunity, and new and improved quantitative management techniques have abounded. This chapter will discuss commonly used computer applications for economic justification of the project, preparation of the cost estimate, planning the work schedule, monitoring work progress, and control of costs and productivity. Finally, there is a review of the degree to which the industry uses these applications. Our experience suggests that while we in the industry have been quick to adopt the new techniques, the quality of our input data has not always kept pace. During the next decade, our push should be toward improving the quality of the basic data and assumptions so that we can fully benefit from the sophisticated techniques. The GIGO (garbage in, garbage out) principle is a wellworn cliche, but it is especially valid here. One of the keys to getting good input is commitment. Unless the managers who are to use or benefit from the system are committed to it, the effort will fail. They must be com- mitted to the underlying principles of planning and control sufficiently to expend their time and resources on them; planning should be especially given emphasis. They can't be too busy to plan.

Jan 1, 1979

By P. E. Damon

An arsenal of isotopic techniques is avail-able that can date the full range of hydrothermal ore deposits. The following are prerequisites for ideal results: (1) Careful collection of samples that are related to the event in a field and process context; (2) Optical examination of the component selected for dating to be sure that it has not been altered; (3) Careful preparation of a pure component of the sample selected for dating; (4) Precise and accurate measurement; (5) Knowledgeable interpretation of the data with reference to decay systematics, properties of the component analyzed as well as the field context and thermochemical environment of the ore process.

Jan 1, 1992

By C. Newman

"As underground mining continues to operate at deeper depths and in more complex multiple seam mining geometries there has been an increased demand for higher design standards in ground control safety and stability within the mining industry. For the past 20 years, NIOSH has developed and validated a number of software tools to aid in the development of safer mining environments with respect to improved roof support performance, pillar stability in longwall and room and pillar mines, formation characterization, the prediction of roof conditions, etc. These tools are available, free of charge, to the mining industry as stand-alone software packages. As cloud computing gains momentum, there is a definite need to develop internet based applications for mine design that would be easily accessible to any user at any time, including underground where permitted. This paper introduces a new web-based product which will allow for faster and easier access to existing ground control designs, on-the-fly calculations in the field as needed, and instant online collaboration between operations personnel and planning engineers. It is expected that the industry will rapidly embrace this product and, as it is common with all new innovative technologies, it will be a new paradigm for mining engineering computer applications. INTRODUCTION Since its release to the public in the late 1980's, the World Wide Web has drastically changed from a collection of static HTML web pages to a dynamic vehicle driving e-commerce, collaborative working relationships, and the mass distribution of information and media (Offutt, 2002). Recent developments in Internet capabilities, such as Cloud Computing and Software as a Service, have begun a migration away from desktop-based software in adoption of the web application (Hayes, 2008). Web applications, or web apps, are designed on the client-server architecture paradigm in which the client, or user, can interact with an application through web browsers without disrupting or installing software on potentially thousands of client computers (Nations, 2015). Currently, web-based software applications are being utilized in all business sectors and markets from commerce, finance, media, and even engineering. In fact, the Alabama Department of Transportation has developed a web-based geotechnical geographical information system (GeoGIS) for the management of and access to geotechnical and subsurface data for transportation projects across the state (Graettinger, et al., 2001). Similarly, Dyno Noble has developed a service application for explosive engineers. The Explosives Engineers' Guide application equips users with a full range of product information as well as on-demand blasting calculations for powder factor, airblast prediction, ground vibration, etc. Through the incorporation of a web server, one is able to utilize the functionality of the desktop-based software through a web browser located on any personal computer, tablet, or Smartphone (Vaughan-Nichols, 2002)."

Jan 1, 2016

By Y. Pan, V. V. S. Vytla, P. Tukkaraja, R. BHARGAVA, S. Jayaraman Sridharan

Panel caving is an underground bulk mining method that utilizes gravitational force for mining massive, steeply dipping, and deep-seated ore deposits at a lower operating cost. To control dust and gas emissions entering the production level during the extraction of ore from the draw points in a panel cave, relatively negative pressure is created in the cave by installing an exhaust fan in the exhaust drift located on top of the cave. Since caving is a dynamic process, the design of an effective ventilation system is a challenging task, and therefore, estimation of airflow resistance offered by the broken rock inside the cave is critical. The complex and dynamic nature of caving also makes it difficult to predict the airflow resistance by using traditional approaches. This study investigates the effect of changes in the bulk porosity of the broken rock on the cave airflow resistance using computational fluid dynamics (CFD) approach. The results show an inverse relationship between the cave airflow resistance and the bulk cave porosity. The pressure-quantity characteristic curves presented in this paper provide valuable information for sizing and operating an exhaust fan used for a mature panel cave ventilation.

May 17, 2022

By R. T. Torrie, J. R. Mernagh, D. B. Chambers

l, INTRODUCTION Uranium mine and mill workers are exposed to external gamma and beta radiation fields from radioactive ore. In the past the average uranium content of ores mined in the United States and Canada ranged from about 0.1% to 1.0% U308 with pockets of much higher grade ore. Holiday (1973) reported that radiation surveys in the U.S. uranium mines found mean gamma "radiation rates ranged from 0.20 to 0.70 mrem/h. Such radiation rates cause relatively insignificant exposures." Others also concluded that the external gamma radiation fields associated with uranium mining did not result in significant worker exposures (Federal Radiation Council, 1967; Simpson, S.D. [et al], 1959) Gamma exposure levels in most modern-day Canadian uranium mines are reported to be low with average annual exposures estimated to be less than 1 rem/a (Frost, S.E. [et al], 1981). However, two developments are taking place which affect the potential significance of external radiation fields in the uranium mining environment. The first development stems from the most recent system of dose limitation developed by the ICRP which is intended to limit the workers' overall risk from exposure to ionizing radiation through the adoption of a sum rule (ICRP 26, 1977) which combines external and internal radiation exposures. In the case of exposure to radon daughters the sum rule will have the effect of reducing the annual exposure limit below the recommended limit by an amount that depends on external radiation and other sources of internal exposure such as the inhalation of ore dust (ICRP 1980). The Atomic Energy Control Board of Canada (AECB) is reviewing this subject and is expected to produce its recommendations shortly. Irrespective of the form of the sum rule eventually adopted by the AECB, it is clear that the net effect of the sum rule will be a collective reduction of the individual dose limits for individual exposure pathways. The second factor is the increasing development of high grade uranium deposits in Northern Saskatchewan. Some of these ore bodies have an average ore grade of 1% to 5% U308 or greater. Since the potential external radiation fields increase in proportion to the ore grade, it is apparent that increased effort in radiation protection planning is required in order to develop safe yet workable methods for mining and milling such ores. This paper is intended to provide information which can be of assistance in the formulation and development of a mining and milling plan. The principal focus of the paper is source identification and the design of radiation protection measures to limit external gamma radiation exposure. The exposure of workers to external beta radiation fields is also discussed. The paper is organized as follows: - Section 2 deals with source characterization. - Section 3 discusses the effects of finite source size and distance (i.e. geometry effects). - Section 4 presents selected data that are useful in evaluating shielding requirements. - Section 5 discusses the potential beta radiation fields. - Section 6 discusses practical data requirements for worker exposure scenarios. - Section 7 presents a variety of work exposure calculations. - Section 8 is a summary of this paper. 2. SOURCE CHARACTERIZATION This section develops the basic formulae for estimating the fluxes and doses from external gamma radiation. The calculation of the radiation flux due to a distributed source (i.e. a linear, area or volume source) as a function of distance assumes that any distributed source can be treated as a summation of point sources. [ ] Uranium ore contains radionuclides from both the decay chains of U-238 and U-235. In this paper the radioactive daughters are assumed to be in secular equilibrium with the uranium parent. (If natural thorium were present in the ore in significant quantities, the gamma rays originating from Th-232 would have to be added to the gamma rays from the uranium series). In all, there are over 50 separate gamma rays (as well as alpha and beta particles) emitted from the U-238 and U-235 radioactive decay series (USHEW 1970). The total

Jan 1, 1981

By Philip R. Whitney

Precipitation of hydrous manganese/iron oxides in streams can be readily observed in much of the northeastern United States, and is apparently a common phenomenon in other glaciated areas (1,2,3,4). Deposition occurs when Mn-enriched ground or surface water enters the stream environment and encounters conditions of higher Eh and pH. The preferred location for deposition is in shallow, fast-flowing segments of stream; the oxides usually form as coatings on detrital material. The experimental studies of Hem(5) and a considerable amount of work on marine and lacustrine manganese nodules(6,7,8) suggest that given an appropriate substrate, deposition of manganese oxides may occur even when the water is undersaturated in Mn with respect to the oxides, due to catalysis by organisms or by silicate, carbonate, or ferric hydroxide surfaces. Once begun, manganese oxide deposition is autocatalytic (9). Studies of the distribution of oxides in various size fractions of stream sediments indicate that the thickness and prevalence of the coatings commonly increases with increasing particle size in the coarse sand and gravel size ranges. Figures 1 and 2 show a fairly typical distribution of leachable metals over nine size fractions from 62 microns up to 8-16 mm. The leaching solution used was neutral ammonium citrate with hydroxylamine hydrochloride, which effectively removes the oxide coatings without significantly attacking most silicates, carbonates or sulfides. Figure 1 shows metal content as ppm of the total sample; figure 2 shows' the same data as micrograms of metal per square millimeter of surface area.

Jan 1, 1975

By F. S. Knoll

GENERAL INTRODUCTION Electrostatic separation has found a number of applications since its initial installation as a processing method. Three broad types of electrostatic installations are discussed in order to provide a practical guide for three widely divergent uses of electrostatic separation. Only operating and installation data are covered in detail. A detailed technical treatment on the various types of electrostatic separation described in this paper can be found in the literature by F. S. Knoll, J. B. Taylor and J. E. Lawer.8, 9 ELECTROSTATIC SEPARATION OF IRON ORE: WABDSH MINES, CANADA Introduction Electrostatic roll-type separator technology which had been in use in various forms since the 1920's evolved in the late 1940's when this separation process was developed and applied to the extraction of titanium bearing minerals from beach sands by J. H. Carpenter. Equipment design and industrial flowsheets developed for the recovery of rutile and ilmenite found new application in iron ore by chance in the year, 1956. From the time of the first beach sands plant, Carpco had developed other technology, gravity and magnetic separation to better serve the beach sands industry. It was in the fall of 1956 that an iron ore producer from the upper Michigan Peninsula sent a sample of jaspilite (fine-grained specular hematite in a jasper matrix) to Carpco's laboratory for the purpose of determining if a new high-intensity magnetic separator would be beneficial. Process Development W. P. Dyrenforth, while presenting a paper on the subject in the fall of 1957, recounts the laboratory tests. "High-intensity magnetic separators have been employed (for the beneficiation of iron ore) with some success and are still being investigated. Magnetic separation is a natural field of investigation, since iron and magnetism have been almost synonymous since ancient times. As a matter of fact, when Carpco first began investigating the possibilities of upgrading specular hematite, the first thought was in terms of magnetic separation; and the second thought was in terms of gravimetric separation. It was found

Jan 1, 1986

By Mohamed A. Younis, Robert J. F. Goodfellow

This paper investigates the design approaches taken and the philosophy employed during the construction of the Metropolitan Airport Commission (MAC) storm tunnels, part of the Phase 4 Segment of the MAC Trunk Storm Sewer Project at Minneapolis St.-Paul International Airport, located in Minneapolis, Minnesota. URS Corporation was retained to provide a design and Construction Management (CM)services for the MAC Trunk Storm Sewer Project. A case history of the design and construction challenges of the project is presented. The MAC storm tunnels consisted of the construction of twin 10-foot inside diameter (I.D.) tunnels within 7 feet of an existing 72-inch I.D. storm pipe at the base of a 70-foot high highway embankment. The analysis required during the design stage of the project is discussed. This analysis and our design approach provided a defensible framework and justification to make design decisions on relevant issues including: allowable spacing of new and existing structures; preferred order of construction; expected ground deformation behavior; response of lining types to adjacent construction; and effects of proposed changes to design at the submittal stage and during construction.

Jan 1, 2003

By B. Petri, N. Rouse

"Air overpressure monitoring procedures and instrumentation guidelines which apply to production blasting in underground limestone mining are not readily available. The industry also lacks an applicable source for air overpressure levels that are produced by blasting operations in underground limestone mines. As such, there was no available background data from which the expected overpressure levels from production blasting in a new underground limestone mine could be predicted. During the development phase of the mine, it was imperative that newly constructed underground structures be capable of withstanding the overpressure produced by blasting in nearby production headings. To ensure the structures could withstand the blast-induced overpressure, a study was conducted to record empirical overpressure data and develop a model which could be used to control air overpressure levels by the production crews. This document describes the procedures used to develop the model, the development of the model, and the applicability of the model for predicting underground blast overpressures. INTRODUCTION A developing underground limestone mining operation required that a ventilation wall be built to house the permanent mine fans. At the time of the study, the mine was a single-level room and pillar operation with a 7.9 meter (26 ft) high roof, 13.7 meter (45 ft) wide entries, and 13.7 meter by 13.7 meter (45 ft by 45 ft) pillar dimensions. The mine is accessed via a 396 meter (1300 ft) long decline and 100 meter (330 ft) deep ventilation shaft. The ventilation wall was to be partially constructed of autoclaved aerated concrete blocks, for which dynamic strength data from explosives loading were unavailable. The company ownership feared that airblast may affect the wall due to the close proximity of the working faces. Therefore, the company management asked that the overpressure levels be estimated and compared with the designed wall strength. Few studies that apply to explosively-driven air overpressure levels in underground production blasting were found through a literature review. Therefore, the logical approach to assess the overpressure levels was to monitor the blast pressures at the site and conduct a thorough evaluation of the data. As a result of this study, the equipment setup and monitoring procedure used to record the airblast data is described. Finally, the experimental data gathered during the monitoring program is presented, trends and findings from the data are discussed, and recommendations for further study are presented."

Jan 1, 2015

By E. Steel

The asbestifom habit is most commonly developed in certain amphiboles and chrysotile, but other minerals may also crystallize with this unususual habit, The habit may be characterized by 1) a fibril structure, single or twinned crystals of very small widths (generally less than 0.5 inn) which have gram with a common fiber axis direction but which are disoriented in the other crystallographic directions, 2) anomalous optical properties, primarily parallel extinction, 3) unusual tensile strength, 4) high aspect ratio, and 5) flexibility. In addition, there is evidence to indicate that some amphibole asbestos may have unusual surface properties.

Jan 1, 1979

By David S. Cahn

For many years the green and dry compressive strengths' of pellets have been, considered as possible criteria of pellet performance during induration. Although widely quoted throughout the industry, little attention has been given to standardizing the unfired pellet compressive strength test or to determining the characteristics of the test. The purpose-of this study was to compare the constant deformation rate test with that using a constant loading rate in addition, the dependence of these tests on such pellet properties as size, weight, and method of balling was to be investigated.

Jan 1, 1967

By B. E. MacNab

During the past several years, Raymond Kaiser Engineers has prepared numerous studies concerning the technical and economic feasibility of coal exporting facilities in the western United States. Perhaps the most striking conclusion to be drawn from these efforts is that many people underestimate the complexity of the highly competitive, dynamic coal marketing system which includes coal loading terminals as an essential but relatively low-cost link in the energy production and delivery chain. The title of this paper, "The Status of Western United States Coal Ports - An Economic Assessment," should not delude anyone into thinking that the future of western U.S. coal- exporting ports has now congealed into a well- defined economic plan. As this paper will demonstrate, the situation is complex and more dynamic than ever and promises to remain so into the late 1980's.

Jan 1, 1982

By Paul C. Miclea

In case of a major fire in a tunnel between stations or ventilation shafts, if the buoyancy effect of the hot gasses is stronger than the airflow induced by the fans, the risk of backlayering could restrict the safe evacuation of people. Obstructions in the tunnel and alternate airflow paths can further reduce the air velocities past the fire. Currently there are two computer programs available to address the issue of underground fires: o "Subway Environment Simulation" (SES), Version 3.0, developed by Associated Engineers, a Joint Venture of Parsons Brinckerhoff Quade & Douglas, Inc., De Leuw Cather & Co., and Kaiser Engineers, Inc. for the U.S. Department of Transportation o "MFIRE", Version 1.26, developed at Michigan Technological University for the U.S. Department of the Interior, Bureau of Mines. As implied by its name, the SES program was developed specifically for the analysis of subway ventilation systems. It can be used to analyze the heat released into, and removed from, a subway or vehicular tunnel and to determine the effect of ventilation elements on airflows throughout the network of stations or other merging tunnels. It has a special feature allowing the user to predict the effects of a fire at any location within the subway system. Version 3.0 of the SES program is designed to be used with a "critical velocity" calculation in order to determine whether or not tunnel airflows can be controlled during a train fire emergency. The original version of the program was written in FORTRAN for mainframe computers, such as the IBM 4381. Recently ICF Kaiser Engineers has compiled a version of the SES program for PC use. The MFIRE program simulates the interdependence between a mine ventilation system, with its pertinent fans and structures, and changes in ambient conditions or a source of heat, such as a fire. It also accounts for natural ventilation. The program is written in FORTRAN 77 and compiled for 8086/8088 based microprocessors, allowing it to be run on an IBM PC or compatible computer with a 2.0 or a later version of DOS, 256K random access memory (RAM), and a text editor. This paper reports the comparative results of an application of both programs for the same network in a recent study.

Jan 1, 1991