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By Lee W. Saperstien

At the heart of the mining process are a number of basic and fundamental tasks whose regular and repeated performance constitute the mining cycle. As will be discussed presently, these tasks are the basic components of the mining system. Section 9, Production Operations, provides the mine designer and engineer with an understanding of these tasks and with sufficient design principles to allow this person to create an efficient mine system. This section is meant to be an introduction and adjunct to subsequent sections that describe specific mining systems. However, sufficient design information is included here for the independent design of mine systems that may not be described elsewhere or for subsequent verification of existing designs. For the purposes of this section, mining subsumes excavation; thus this material applies to any excavation process. Accordingly, this section is written in general enough terms to include both surface and underground mining. It may be used also for civil engineering excavations that often involve the same steps. Obviously, the actual procedures undertaken in any specific mining system will appear to be very different from those taken in any other system. This is certainly true when comparing surface with underground methods. Yet the fundamental principles are often the same. This segment is written to explicate the basics. Wherever appropriate, the section will suggest the differences between the application process to surface or to underground mining.

Jan 1, 2008

By Maryam Sadeghi, Jonathan Roy, Claude Bazin

"The operation of mineral processing equipments is intimately related to the mineral composition of the ore. However unit performances are usually characterized in terms of metal contents or recoveries as this data is easier to obtain than the mineral contents. This paper describes a method that combines the operations of material balancing and estimation of the mineral contents of the ore. The estimated mineral contents can be used for process analysis and diagnosis of operating problems.IntroductionThe ore that is feeding a concentrator is made of minerals that condition the energy requirements for the ore comminution and the performances of the subsequent separation circuit. Indeed a change in the mineral composition of the ore may lead to lower grinding mill throughput as well as lower recovery or grade of the economical products. Despite this relationship is recognized the mineral composition of the ore is seldom measured or estimated to provide regular information for the diagnosis of operating problems. Some methods such as the QEM-SCAN (Whiten, 2008; Lamberg and Vianna, 2006) are available to measure the concentration of the minerals in ore samples but the method is time demanding and plant operators usually base their evaluation of the plant performances on chemical assays of metals or elements since this data is easier to obtain from ore samples.Usually samples of the streams of mineral processing plants are collected on a daily basis to be assayed for strategic elements. The obtained concentrations are balanced to produce coherent data with the material conservation constraint and then used to characterize the day to day operation of the plant in terms of recovery of valuable metals and grades of the marketable concentrates. The behavior of contaminant elements can also be monitored from this data allowing the operators to explain for instance a lower zinc concentrate grade by a more important contamination of iron. However such diagnosis is only partial as the contaminant element can be transported by different minerals. Indeed the iron contamination of a zinc sulfide concentrate may be caused by an inadequate depression of pyrite or due to another iron carrying mineral. A possible way to answer the question is to determine the concentrations of the various minerals in the ore and produced sealable concentrates. Since measuring the mineral contents of the ore could be a demanding task one should consider to estimate this data from the daily chemical assays of the sample collected on the main streams of the circuit. Some authors have already investigated the problem. Whiten(2008) described a method to estimate the mineral contents of an ore sample. Lamberg and Vianna(2006) proposed a method to do a sequential mineral reconstruction followed by a material balance. Few of these methods account for the mass conservation of the reconstructed mineral contents."

Jan 1, 2016

By D. Bessinger, J. Nell

The electrical conductivity of rutile was optimised as a function of time, temperature and gas composition. These optimised conditions were used to treat rutile/zircon feed prep concentrate samples from a South African heavy minerals producer, prior to electrostatic separation. Enhanced separation between rutile and zircon was obtained when compared to untreated samples. Samples treated in a hydrogen atmosphere and cooled in nitrogen showed the best separation when passed through a high tension electrostatic separator using conditions of high sample temperature and high relative humidity.

Jan 1, 2005

By Thomas M. Barczak

Advancements in support technology have occurred to a large extent because of the demands of the mine operators. Shield supports are no exception. The most notable changes in shield technology in the past decade have been increases in shield capacity and life expectancy, which have increased by a factor of 4 and 7 respectively since the inception of the shield support 25 years ago. The purpose of this paper is to set goals for the future generations of longwall shields. These goals include: (1) 100,000 cycle life expectancy, (2) improved hydraulic diagnostic capability, (3) smart load control with adjustable setting pressure algorithms, (4) composite material design to reduce weight and increase shield width, (5) constant set leg cylinder design, (6) improved joint design to reduce wear and stress, (7) advancements in leg cylinder socket design, and (8) an instrumented shield to measure in-service structural component loading. These design issues will continue to push the envelope in longwall shield technology that has provided the safest and most productive mining system employed in the history of mining. In preparation for this, a historical examination of shield failures is made and recent trends in shield design are evaluated. Design practices to improve structural margins of current designs are also addressed.

By S. H. Ash

THE MAGNITUDE of the anthracite industry's drainage problem in the Lackawanna River drainage area is realized when it is known that in 1948 the 27 pumping plants in this region pumped over 48 billion gallons of water to the surface from the mines in the Lackawanna Basin of the Northern field. This is almost 92,000 gallons per minute pumped against an average hydrostatic head of over 300 feet for that year. By comparison, Lake Wallenpaupack, the largest artificial body of water lying wholly in Pennsylvania, contains 71 billion gallons of water in its 24-square-mile area: the volume of water pumped from the mines in the Lackawanna Basin during 1948 was approximately 68 percent of that impounded in Lake Wallenpaupack. The Lackawanna. River and its tributaries drain a troughlike area of 345 square miles. The synclinal axis of this trough lies within the coal measures. All surface drainage into the valley must traverse some part of the coal measures. On the basis of 45.03 inches of rainfall recorded by the Scranton station of the United States Weather Bureau for 1948, the runoff from the Lackawanna River drainage area during that period was 135 billion gallons, approximately three times the volume of water pumped by all mine pumping plants in the Lackawanna. Basin of the Northern field during 1948. In other, words because of the pervious condition of the strata overlying the mine workings, approximately one-third of the total runoff in the Lackawanna River drainage area becomes mine water. This report, reveals that less than 7 percent of the 72 miles of pervious stream beds examined between Archbald and Pittston have been unproved.

Jan 1, 1952

By Javier Támara

Para aumentar la productividad de la empresa minera es necesario conocer el sistema de aire -en tanto se prioriza los intereses de los clientes, y así se puede suplir todos los componentes necesarios para garantizar una máxima eficiencia y confiabilidad del sistema completo de aire comprimido que va desde el filtro de admisión hasta el punto de uso. En ese sentido, el presente texto describe las estrategias para realizar Solucionazing en ahorro energético y así aumentar la produtividad de los sistemas de aire.

Aug 25, 2002

By Charles Knilans, Tassos Grammatikopoulos, Nicole Hoffmann

"Twin Metals Minnesota LLC, (TMM) has recently completed a prefeasibility study evaluating the development and operation of an underground copper (Cu), nickel (Ni), platinum (Pt), palladium (Pd), and gold (Au) mining project on the Maturi deposit in northeastern Minnesota.The Maturi deposit is a magmatic Cu-Ni-sulphide deposit occurring along the basal contact of the South Kawishiwi intrusion, comprised of heterogeneous troctolites to gabbros forming a tabular body designated the BMZ (basal mineralized zone). These rocks provide the major gangue mineralogy (plagioclase, olivine, and clinopyroxene) with local, minor rock-forming orthopyroxene, biotite, magnetite, and ilmenite. Altered silicates exist within local fracture and/or alteration zones, which are commonly associated with minor faults in the regional area. The Maturi deposit is comprised of four main mineralized zones within the BMZ, referred to as Stage 1, Stage 2 (S2), Stage 3 (S3), and Upper Heterogeneous. Chalcopyrite, cubanite, pentlandite, and pyrrhotite are mainly hosted within the S2 and S3 units, with talnakhite frequently occurring within the S3 unit.A cross-discipline approach combining geology, geochemistry, metallurgy, QEMSCAN™ mineralogy, and mine planning has been implemented to develop a preliminary geometallurgical model and life of mine metallurgical performance forecast. This paper provides an overview of the methods that were used to develop the model and forecast, and discusses the advantages of such a model in project development and evaluation.INTRODUCTIONThe TMM Project proposes mining a copper-nickel-palladium-platinum-gold-silver (Cu-Ni-PGM) magmatic sulphide deposit situated in the Duluth Complex of northeastern Minnesota, USA. The prefeasibility study proposes a 45,000 million tonnes per day mine and concentrator facility to produce two saleable concentrates. The mine will access two separate deposits, Maturi and Maturi Southwest. Saleable concentrates are the final products of the sequential flotation plant where a high grade Cu concentrate is produced followed by a Ni concentrate."

Jan 1, 2015

By H. R. Babitzke

As part of a continuing project to develop refractory metal alloys for high-temperature structural applications, the Bureau of Mines applied solid solution and precipitation strengthening techniques to improve the properties of columbium alloys. The purpose was to investigate the effects of hafnium, tungsten, and boron on the formability, strength, and oxidation resistance of columbium. The experiment was of factorial design with two replications which called for 72 ingots of 36 basic compositions, weighing 150 grams each. Hafnium, tungsten, and boron were evaluated at 3, 3, and 4 levels, respectively. Values of alloy content are all in atomic percent. The highest strength observed was 29,000 psi at 1,200° C for alloys Cb-15Hf (No. 3), Cb-7.5Hf-5W-2B (No. 14), and Cb-15Hf-5W-2B (No. 15). At 1,200° C, the ternary alloy Cb-15Hf-5W (No. 6) which has shown good properties in previous Bureau of Mines investigations was the most resistant to oxidation For boron additions, the alloys oxidized more readily with increasing amounts of this element. The fabricability of the alloys high in boron became increasingly difficult, resulting in an inadequate number of alloys required for a complete statistical analysis for all the tests. As a result of the decrease in ductility, an insufficient quantity of tensile samples were available for a proper analysis for the high-temperature strength data.

Jan 1, 1970

By Xinzhi Du

Coal strength is essential to analyze the stability of excavation in coal. It is well known that the strength of coal tested in the laboratory is size-dependent, and different size specimens will produce different strength. Many researchers have studied the uniaxial compressive strength of coal and developed a number of empirical formulae to describe the strength variation with specimen size. According to a comprehensive data base that includes most of the laboratory testing results in the last century in U.S. and South Africa, the size effect and shape effect were reviewed and analyzed. The results show that different groups of coal specimens have different size effect on the compressive strength. The critical size for the size effect from the data analysis is about 40 in. The shape (W/H) of the specimens has a large effect on the compressive strength. The pillar strength formulae obtained from the data regression have a larger strength than all other existing formulae. Most pillar strength formulae have their own place in coal pillar design field. In order to analyze the difference of those formulae, twelve design formulae have been selected to compare using the Pittsburgh coal seam. The intention is not to determine the preferred formulae, but only to compare them, and see how do the W/H ratio, width, length, angle, cross-section area and effective width affect different pillar strength formulae?

Jan 1, 2008

By B. B. Broms

The high transverse tensile stresses that develop in precast concrete piles during driving have been investigated experimentally from pile load tests and theoretically using the finite element method (FEM). These tensile stresses can be high enough to cause longitudinal splitting of the piles just below the pile cap. Test data and FEM indicated that the maximum transverse tensile stress will increase with increasing thickness of the cover. The maximum tensile stress can be high especially if the pile is eccentrically loaded. The results from the experimental investigation and from FEM are described in the paper as well as a simplified method based on the stress distribution in a concrete cylinder at an indirect tension test.

Jan 1, 2010

By N. Niemuth

Strong demand for copper in developing nations such as China and India, plus the additional demand for industrial minerals to supply the Arizona construction market, brought about a record-setting year for the state?s mining industry. The value of Arizona?s copper production set a new high of $5.5 billion and pushed the total value of mineral production to $7.58 billion. This was also a record. As it has for many years, Arizona ranked first in nonfuel mineral production in the U.S. In addition to leading the nation in copper, Arizona ranked in the top five in molybdenum, sand and gravel, gemstones, perlite, silver, zeolites and pumice. Generally strong and rising prices, especially toward year?s end, fostered a bullish atmosphere that encouraged significant levels of acquisition and exploration. This activity has spread beyond the normal commodities to include some, such as manganese and fluorspar, that have not been mined in Arizona for decades.

Jan 1, 2008

By M Vendrup, T C. Christensen, C Dube

The adsorptive and granulate forming MetClean™ process has been used at many locations in Northern Sweden, Norway, Denmark, France, Spain, Mongolia, Japan and Australia. It has been pilot tested and used in full scale treatment plants to remove metals from:mine watersleachate from solid waste in incineration flue gasleachate from fly ash damsleachate from landfill and waste ponds.The following paper provides details of pilot and plants tests on the effectiveness of MetClean™ in removing arsenic, antimony, barium, cadmium, copper, molybdenum, nickel, radium, uranium, vanadium and zinc. Results show that MetClean™ may reduce the concentration of these metals in treated effluent water to the one part per billion (ppb) range.The paper also finds that, for specific metals, the optimal adsorption condition depends on the:pH levelmolar relation between the specific targeted metal and the addition of iron (II) or manganese (II)type of oxidation agentssalinity levelpresence of other metals.The most effective pH level varies according to the targeted metal but falls within the pH 5 to pH 11 range. A compromise pH level may be set when more than one metal is targeted for removal at the same time and through only one process step. The removal efficiency of one or both metals may be affected by operating at a compromise rather than optimum pH level.The MetClean process generates non-hazardous solid waste. Waste can then be disposed of more easily than brine or sludge.CITATION:Christensen, T C, Vendrup, M and Dube, C, 2015. Pilot tests for heavy metals removal in mine water, in Proceedings MetPlant 2015, pp 404–415 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By Doug Tesarik

Researchers from the National Institute for Occupational Safety and Health1 (NIOSH), together with employees from The Doe Run Company, are monitoring and evaluating the stability of a pillar retreat section at the Fletcher Mine, a lead/zinc, room-and-pillar mine near Bunker, MO. Cemented rockfill is being used to provide roof support as high-grade, remnant ore pillars are mined. Earth pressure cells and deformation meters placed in backfill panel pillars monitor stress change and vertical deformation, respectively, as nearby ore-bearing pillars are extracted. Similarly, biaxial stressmeters and borehole extensometers are used to monitor mining-induced stress change and deformation, respectively, in long-term support pillars. Data from these instruments indicate that when ore-bearing pillars were mined, stress was redistributed from support pillars to a backfill panel pillar. The data also indicate that the backfill and support pillars have remained stable for two years after pillar extraction was completed in the area. This research demonstrates the importance of using reliable instruments to document the geomechanical behavior of pillars and backfill. Gaining a better understanding of roof support and stress redistribution mechanisms is a fundamental part of NIOSH's goal to reduce and/or predict rockfalls, which are still among the leading causes of injuries in metal/nonmetal underground mines.

Jan 1, 2006

Producers with Zero Reportables 2007!: ?New Horizon Mine, Western Fuels Colorado LLC ?Isaacs Run HWM, ICG ADDCAR Systems, LLC ?Savage Mine, Westmoreland Savage Corporation ?South Hallsville No 1 Mine, Sabine Mining Company ?Black Butteand Leucite Hills, Black Butte Coal Company Black Butte and Leucite Hills, Black Butte Coal Company ?Buckskin Mine, Kiewit Mining Group ?Coal Creek Mine, Thunder Basin Coal Company, LLC

Jan 1, 2008

By N. Som

The pile capacity in cohesive and granular soils depends on a number of parameters. The values of these parameters as recommended by Indian Standard Code of Practice vary over wide ranges. A designer often finds it difficult to select appropriate values of these parameters for realistic estimate of a pile capacity. The present paper makes a critical review of the values of the parameters given in Indian Standard Code of Practice and suggests a realistic approach to selecting them in the light of recent research.

Jan 1, 1996

By J. D. Potts

Dust surveys were conducted at six underground coal mines to determine if deep-cutting practices expose face workers to higher levels of respirable dust. The surveyed mines were able to successfully mine deep cuts without significantly increasing the dust exposures of face workers. For exhausting face ventilation, field data indicate that scrubber airflow is the most important factor for controlling dust. Data collected for this study indicate that 20-mesh screens should be cleaned for every 40 ft of advance because 22% of the deep cuts surveyed for this study experienced a 20% to 35% decrease in scrubber airflow over the course of the cut. For blowing face ventilation, field data and past research indicate that dust control is aided by maintaining a proper curtain-to-scrubber airflow ratio of 1.0 (measured before scrubber activation) as well as a curtain setback distance that allows the miner operator to stand at the mouth of the curtain for the entire cut. Dust levels on the bolting faces did not appear to be affected by the longer cycles associated with deep-cut mining when good ventilation practices were used.

Jan 1, 2011

By Rudi Podjadtke

In a short chronological review the development concepts and improvements in steel roadway support are shown. The successful standardization concept of RAG Deutsche Steinkohle and currently used support systems are important topics. The history of optimizing the material properties for the steel arch support with different alloys up to the tempering used today is discussed. The present-day application of the steel support is additionally presented. Today, it represents a system component of modern roadway support also for highly stressed roadways. In addition to the yielding roadway arch support, this overall system - the combination support - consists of the additional components of a rockbolting system and concrete backfilling. The comparison of the application areas for each individual partial system with the overall system illustrates its high performance capability. Actual practical experience with the state of the art typed steel arches are pointed out exemplarily. Understanding the complete system permits the selection of the economically optimal support for all conditions.

Jan 1, 2008

By Peter Chou

A total of 117 slope stabilization drilled piers were installed as part of a major hillside revitalization project. The 110-million dollar development, known as Stratford at Kenwood, included an 18-story upscale senior residential tower, a 3-story healthcare building, and 4-story condominium buildings, offering approximately 580,000 square feet of living space with panoramic views of Downtown Cincinnati, Ohio. In an effort to establish a flatter hillside plateau for the new 4-story condominium and to create a cut and fill balanced jobsite environment, an 800-foot long row of drilled piers and a 600-foot long multi-tiered shear key system was used to terrace existing 1.5H to 3H: 1V steep slopes and support the new fill. These slope stabilization features reduced the amount of spoils needed to be wasted off-site and mitigated the risk of slope instability. An ODOT/FHWA research indicated that spacing of stabilization piers and necessity of top-connecting elements are highly dependent on pier diameter, spacing, soil type, depth to potential failure surface, surcharge loads, and pier deflection. Due to pre-existing deep buried swales, various load combinations, and the complex mechanism of soil arching effects between adjacent piers, both analytical and numerical computer modeling was performed to estimate the loading on each pier. New generation multiplexed, 3-Dimensional, Micro-Electro-Mechanical-System based inclinometers were installed between selected piers to confirm the pier design, and monitor the fill placement, as well as long-term slope stability.

Jan 1, 2009

THE slide-rule, as a quick and convenient instrument for performing approximate calculations, is steadily growing more and more into favour with the engineer, and results obtained by it are considered close enough to enable him to satisfactorily dealwith a considerable portion of his work. To the surveyor, however, whose ordinary computations must be as precise as his measurements, the present makes of rule are insufficient, except for a very narrow margin of the scales and for rough work. Few will carry the rule when they can clearly see that it is unreliable for general routine, and the careful surveyor is inclined to look askance at those who do use it, recognizing the temptation there undtmbtedly must be to push it into work that the log book should be called upon to treat. From the fact that a surveyor's duties take him on the surface in all weathers, and underground in many wet and uncomfortable places, where the manipulation of a book of mathematical tables becomes both awkward and patience-trying, an efficient slide-rule must offer the mbst transparent advantages. Again, a surveyor being specially trained to read divided scales quickly and accurately, the slide-rule must commend itself as an apt addition to his outfit.

Jan 1, 1912

The district specially referred to in this paper comprises the very gently sloping country extending from the western shores of Port Phillip from the mouth of the Yarra to Footscray along the Bacchus Marsh railway to near that town thence in a southerly direction to the Little River, and along that river to the coast, 1 as may be seen on the accompanying map. Almost the whole of this area is covered by volcanic rocks, consisting of pumerous sheets of basalt, which have been poured out of various volcanic hills in the districts, such as Mts. Atkinson and Cotteril, near Melton; Mt. Maryand Bald Hill, 12 and 16 miles respectively N.W. of Werribee; and vents in different parts of the parishes of Tarneit, Mouyong, Mooradoranook, Pyweitjorrk, and Derrimut. These volcanoes were in an active state of eruption during a late period of the earth's historyprobably the late Pliocenll, or still younger Pleistocene.Occupying a narrow strip of country, for most of the distance along the coast from Williamstown to past the mouth of the Little River, there occur deposits of still younger age, belonging to the Recent period. These lie on the basalt, and extend for distances varying from a few chains to more than a mile back from the beach. They comprise superficial deposits of blown sand, and raised beaches, composed of marine sands...

Jan 1, 1902