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By Kevin D. Lofftus

This paper presents a dynamic model for column flotation. The model equations are normalized and the dimensionless groups that are directly responsible in determining the column flotation behavior are identified. The resulting model equations are incorporated for computer simulation. Numerical results from computer simulations are analyzed to gather information about design and operation of column flotation devices.

Jan 1, 1988

By Monica Pavlik, Thomas Wildeman

Water from the Forest Queen mine adit near Silverton, Colorado drains into a natural wetland. Because the pH of the water averages 5 and the iron concentration averages 18 mg/L, it was thought that the wetland might naturally treat the water. Of most concern with respect to the aquatic environment is zinc whose concentration averages 0.60 mg/L. Starting in October 1997, the surface waters, ground waters in the peat substrate, and the sediments in the wetland were sampled and analyzed four times over the course of four months. The adit water primarily remains as surface water where Fe, minor amounts of Al, and no Zn are removed. After the adit water enters the peat, then it is found that the pH rises to 5.8-6.5 and sulfate is reduced. The removal of Zn and A1 is caused by these two changes. However, Fe in its reduced state is quite soluble and may be remobilized in the reduced environment of the peat.

Jan 1, 2000

By K. J. Stratford

The selection of a suitable mathematical function for the modelling of the partition curve for dense medium cyclones is discussed. Five alternative functional forms (based on three basic functions) are compared using data obtained in the course of an extensive experimental study of a 610mm dense medium cyclone. It is shown that, for adequately sampled tests, any of the functions may be used, although a function based on the Weibull distribution is shown to be most suitable. Where data are poor, all functional forms exhibit disadvantages, notably in terms of a reduction in precision of parameter estimation. This problem can be exacerbated by the complex numerical techniques required to estimate the parameters of a particular function. A set of ideal requirements for a performance function are presented.

Jan 1, 1986

By S. K. Kawatra, S. J. Ripke

Iron ore pellets use bentonite clay as binder at dosages from 0.5to 1.0% (10 to 20 pounds per ton) of moist iron ore concentrate. Bentonite is typically shipped hundreds of miles from Wyoming to the Lake Superior iron ore district. It is therefore best to know how effective a bentonite will be before it is shipped and used to bind concentrate into pellets. Current tests of bentonite effectiveness include: plate water absorption, methylene blue uptake, free swell, exchangeable cations, and glycolated layer expansion. However, these tests have many disadvantages: First, they only measure the ability of a bentonite to expand, disperse, or absorb, not how well it will bond. Second, most of the tests require up to 20 hours to perform. Bentonite only has a few minutes to interact within the concentrate before it is indurated (sintered). These long-term tests may not reflect the true behavior of bentonite. Third, the tests are tedious and often results are inconsistent between different iron ore concentrates, labs, and technicians. Fourth, some of the testing equipment is difficult to procure. Fifth, procedures are often difficult to standardize. In this paper, the Binder Effectiveness Strength (BESt) test to evaluate binders for iron ore pellets is presented that: measures the ability of bentonite to bond, requires only about two hours to complete, is simple and reproducible, and utilizes readily available equipment that has been standardized for decades.

Jan 1, 2003

By Thomas C. Wilder, Firoze E. Katrak

As part of a survey on the long range supply of gallium, a comprehensive review of the chemistry of commercial gallium extraction was undertaken Owing to its very small concentration in all commercial minerals, gallium can be produced economically only as a by-product of major extraction processes for other materials. A summary is presented for the chemistry of gallium extraction from many of these process streams included are several procedures for gallium recovery from bauxite, currently the most prevalent source Other processes described are from waste streams from the production of zinc, phosphorus from phosphates, aluminum from kaolin clays, and from coal ash, the largest potential resource A brief review of development of solvent extraction as a unit process for gallium recovery is also presented

Jan 1, 1983

By R. Frenette, A. W. Mo, H. A. Hamza

Fine particles present major technical and economic problems to those who deal with solid/liquid separation processes. In the coal industry the problem is compounded by the large amounts of produced fines such as those present in Western Canadian coals. Flocculants in the form of high molecular weight water soluble polymers are commonly considered an effective solution for the enhancement of the separation process. These reagents are relatively expensive especially when considering a low-price commodity such as coal. Optimization of the use of these reagents is therefore an operational necessity. Six polymers were evaluated as to their effectiveness in flocculating a fine coal tailing. Results were compared with those for a reference flocculant, in-use at that time in the washery. It was shown that, in general, flocculants significantly improve the solid/liquid separation process. The ranking of the flocculants as to their effectiveness in settling and filtration indicated that the best flocculants for settling were not necessarily the most effective for filtration. Flocculants that showed the best filtration improvement were generally cationic and those best for settling were anionic.

Jan 1, 1988

By Haydn H. Murray

The three major catalyst markets that utilize industrial minerals as raw materials are petroleum refining, chemical processing, and emission control. Because of economic, competitive, and regulatory pressures, catalyst producers are pushed to develop products with improved performance to meet changing environmental standards. Also, refiners are demanding new families of cracking catalysts that will crack residual fuels. In 1987, worldwide cracking catalyst sales amounted to $457 million (Occelli, 1988a). Recently enacted federal and state laws to improve air quality have prompted strong growth for environmental catalysts, which in 1989 accounted for more than a third of the $1.9 billion catalyst market in the United States (Farrauto, Heck, and Speronello, 1992). A catalyst is a material that promotes or enhances a chemical reaction but does not itself enter into the reaction. One of the more important mineral groups used as catalysts is clays. The first recorded use of clay as a catalyst was its use in the dehydration of alcohol (Bondt et al., 1797). Clay minerals that are used as catalysts are kaolinite, halloysite, smectite, palygorskite, and sepiolite. Minerals used as catalysts, catalyst supports, or as a raw material to make zeolites are kaolinite, halloysite, sodium montmorillonite, calcium montmorillonite, hectorite, palygorskite, sepiolite, talc, calcined kaolinite, gibbsite, chlorite, and titanium dioxide.

Jan 1, 1994

By William J. Ferguson

At Henderson Operations the 24-kilometer conveyor system consists of three main conveyors with lengths of 1.2 km, 16.7 km and 6 km. Upon commissioning of the conveyor system, the Henderson maintenance department was challenged with the inspection and monitoring of over 50,000 idlers. To take a proactive approach to idler maintenance, an idler tracking database system was developed. Using the idler tracking program, the Henderson Crush & Convey department now has the ability to provide data for engineering solutions to idler problems and to manage thousands of idlers for priority replacement work and warranty purposes. Recognizing the potential for injury to Henderson employees in the process of idler handling, Henderson approached idler replacement as a material handling process. Material handling solutions have resulted in failed idlers being replaced and discarded from the underground environment without ever touching a human hand. This paper will detail how Henderson tracks idlers in all primary conveyor belts and how an innovative idler handling system can result in reduced risks to conveyor maintenance employees.

Jan 1, 2004

By Elif Çevik

This study deals with the mineralogical-geochemical characteristics and the industrial usage of the olivine from the dunites that crop out on the west of the Topuk village (Orhaneli). Mineralogical compositions of non-altered dunite samples are averagely as: Olivine (>90%), serpentine (1-4 %), opaque minerals especially chromite, magnetite, pyrite (1-3 %), and secondary minerals as magnesite, chlorite (1-2 %). X-Ray Diffractograms of the dunite samples indicate that olivines are in forsterite (93 on an average) composition, and chlinochrysotile and lizardite accompany to the forsterite. Chemical analyses of the dunites show that MgO, SiO2, Fe-,03 and LOI contents vary from 40,99 to 50,2 %, 34,67 to 40,6 %, 6,8 tol3,7 %, 0,11 to 11,27 %, respectively. SE-TAT Mining Company states that the study area has 400.000.000 tonnes proved, 800.000.000 tonnes probable and totally 1.200.000.000 tonnes olivine reserve. Consequently, all studies indicate that Orhaneli Olivin has convenient mineralogical and chemical properties and the grain size (0.04-40 mm) for industrial usages such as abrasive, olivine sand products, steel slag conditioner, balast and covering material in industry: Orhaneli olivines are demanded especially from the firms related to refractory industry, iron-steel factories, naval forces and shipyards. SE-TAT Mining Company also exports these olivines to different countries such as Macedonian and Spain.

Jan 1, 2005

By Yuusaku Tominaga

A flexible expert system for a personal computer has been developed to take countermeasures for prevention of emergency in underground coal mines. The system makes a diagram to estimate maximum airflow rate of a specified branch such as coal face or advancing face, etc. under the conditions of opening regulators set in any two different branches, by computer simulation. The system approximates the ventilating condition underground by using both measured values and safety factor derived from the rules in the system. The probability of happening gas explosion, spontaneous combustion and mine fire underground is shown on a display and countermeasures in a data base in the system are selected according to a confidence factor. When it is recognized in the system that either safety factor or confidence factor of countermeasure has a small value, the system sends information relating to reasoning in the system to registered human experts by computer communi¬cation and facsimile. The replies in file transfer from the experts are stored in the system and reconsultations for estimation of underground condition are started automatically. As the replies in facsimile are shown on the display, user inputs new rules and, values for reconsultation. It is shown that the system is available to take better countermeasures as the condition' of a network in coal mine is changed by mining day by day.

Jan 1, 1992

By Richard R. Klimpel

This paper reviews some of the factors involved in selecting amine flotation reagents used to remove silica from ores. A comparison is made between the chemical reagent design approaches used to identify flotation reagents that are used to recover silica- and oxygen-containing minerals and the chemical reagents used to recover sulfide minerals. This introduction gives practitioners who are involved with oxide- and carbonate-type minerals and who may not be familiar with sulfide mineral flotation some ideas of the chemical reagent design challenges that exist with froth flotation on a broader scale and why oxide type mineral flotation reagents are what they are. This is followed by several sections that discuss various classes of available amines. The closing sections emphasize that the optimal choice of an amine collector depends not only on that amine's specific chemical characteristics and costs but also on the operating conditions, especially the flotation feed particle size distribution.

Jan 1, 1999

By J. R. Caylor

The Mine Safety and Health Administration (MSHA) advanced several initiatives last year to further protect miners' health. Regulatory efforts included the implementation of a Hazard Communication rule for all mines, work on the Single Sample rule for all coal mines, and the Plan Verification rule for underground coalmines. Development and application of new technologies are actively encouraged in preventing miners' hearing loss and respirable dust overexposures. MSHA's successful x-ray program for screening of black lung among coal miners completed its third year. Compliance Assistance efforts are focused on Best Practices, outreach, and technical support for operators' specific challenges.

Jan 1, 2003

By James J. Scott

Introduction Friction Rock Stabilizers, trade name Split Sets, are presently under research and development by Ingersoll-Rand Company and Dr. James J. Scott, inventor. Conceived in 1953, the system is a patented process undergoing extensive field and laboratory testing. The author has published papers on the Split Set System earlier (References 4, 5, 6) The Split Set System holds promise to be a revolutionary development in the field of ground control. The system produces an interior reinforcement to a rock mass which: 1. Is simple in its concept. 2. Adjusts to the degree of restraint needed to match rock properties. 3. Provides a yieldable support and, later, a more rigid support as it is needed. 4. Pre-loads the rock in compression to increase stability. 5. Is a full-contact, fully tensioned device to resist rock loads. 6. Minimizes the stress concentration effects inherent in many interior support devices. 7. Improves safety for the miner. 8. Is cheaper than a grouted system. 9. Offers the rock mechanics engineer an opportunity to design in a fashion not before possible.

Jan 1, 1977

By M. Stefanakis, A. Kontopoulpus, K. Adam

The application of Bacterial Oxidation as a pretreatment step for the extraction of gold from the Olympias refractory pyrite concentrate is described. A wide review of Bio-oxidation is presented focusing on the current process developments and commercial applications relevant to the treatment of gold bearing sulphide ores and concentrates. Preliminary batch and semi- continuous tests on the Olympas concentrate indicated that with Bacterial Oxidation quantitative gold liberation may be achieved. fie effect of such parameters as pH, Eh, temperature, particle size, operating pulp density and retention time on the extent of sulphur oxidation and subsequent gold extraction by conventional cyanidation are also examined. Finally, a preliminary evaluation of Bacterial Oxidation as a potential process alternative for the treatment of the Olympias concentrate is presented.

Jan 1, 1989

By D. A. Stanley, B. J. Scheiner

The U.S. Bureau of Mines has thoroughly investigated the flocculation of phosphatic clay waste with polyethylene oxide (PEO). The studies included both theoretical and applied aspects of the flocculation sequence. The screen dewatering technique developed by the Bureau was field tested at four different Florida phosphate mines. The results of these field studies are presented. Also, to determine the mechanisms of the interaction of PEO with montmorillonite clays common to the phosphatic clay waste, a number of theoretical studies were conducted. An empirical equation was developed to describe the amount of PEO needed for flocculation. Infrared, ion exchange, and rheology techniques were used to study the interaction of PEO with Florida clays. The results of these studies are also presented.

Jan 1, 1993

By V. Perdikatsis

The aim of this paper is the study of the pollution of soils in greenhouses because of the use of pesticides. The degree of pollution was studied in relation with the mineralogical and pedologic properties of the soil. The study was con-ducted in the region of Kountoura, Palaiochora, situated in the south of the prefecture of Hania/Greece. Several samples of soil, originated from 4 greenhouses were analyzed. 5 pesticides with organic drastic compounds were chosen for analytical determination using GC-MS from 18 which were applied in total during the period of sampling. It was concluded that the adsorption of pesticides in the soil of greenhouses is connected with the percentage of the clay fraction and the content of organic carbon.

Jan 1, 2006

By E. J. Meets, C. F. Meyer

Bord and pillar mining at shallow depth (400 m approx. maximum) is widely used in South African coal mines. One of the problems encountered in extracting coal in this manner is the ventilation of advancing bord and pillar headings. The traditional ventilation methods of force, exhaust and overlap (force/exhaust) are reasonably effective but tend to be both cost and labour intensive. Ducting often restricts the available free area of roadways thus impeding the transport of coal and other materials inbye the coal production section. Due to the above facts, ductless fans are currently being used to minimize the amount of ducting required in advancing sections. Two different types of fans are used, namely, vortex fans and the so-called `jet' fans. Vortex fans were developed from the fan blade design used for vertical take-off aircraft. The fans have the capability of delivering air over distances of about 30 m in the underground situation without any ducting attached to it. Jet fans are standard axial flow fans fitted with outlet reduction pieces which increase the velocity pressure at the discharge to such an extent that the air delivery distance is improved to almost match that of vortex fans. The paper describes some applications of both these fan types in advancing bord and pillar sections.

Jan 1, 1993

By Lijun Xu, Ragula Bhaskar

The transport of dust particles from a turbulent air stream on to the surface of a mine entry is mainly due to the effect of diffusion, sedimentation and inertial impaction. While the literature in aerosol science contains many references on particle deposition, most studies apply to smooth surfaces in small, short tubes. The deposition data from those experiments may not be applicable to deposition in mine airways that have large areas of rough surfaces and extend several thousand meters. This paper describes the mechanisms of mine dust transportation and deposition, specifically, by estimating the turbulent deposition velocity for coal dust in mine airways. Data from in-mine experiments on ambient dust concentration and dust deposition along a straight entry were used. A statistical model for dimensionless turbulent deposition velocity was developed, and compared with the models developed by other researchers. The model shows that the distance from the dust source is an important factor in the turbulent deposition of mine dust.

Jan 1, 1995

By Liu Cheng-si

The number of control plans for placing control devices in a ventilation network is surprisingly large, but the research result indicates that not all control plans are feasible. The feasibility of a ventilation network control plan depends on two factors. One is the influence of the network structure. The structure must contain one independent variable-flow airway in a non-controlled loop. Otherwise, the control plan is unfeasible. The other is the combination of the air resistance, quantity, pressure and other parameters. Under some conditions, the selected values of these parameters may result in an unfeasible plan. As to the influence of the network structure, when the network structure is simple, the feasibility of a control plan can be judged directly. However, for the influence of the parameters, the feasibility of a control plan must be examined through calculation. The control position has been extended into the natural-splitting subnetwork from the conventional constant-flow subnetwork. This technique is theoretically significant. The extension of control positions results in a great increment in control plans and variation in parameters. At present, the calculation methods of the ventilation network control plans are all available. They are quite useful in selecting desirable plans. However, among the plans found, some are impractical or even unfeasible. If the unfeasible ones can be eliminated at first, much time can be saved in design and calculation. This also facilitates management and decision making.

Jan 1, 1991

By G. Papantonopoulos

Natural stones are extensively used for construction purposes since the dawn of human civilization, due to their unique aesthetical and technical characteristics. Their production and consumption has been continuously increasing over the past twenty years worldwide at an annual rate of 8.8%. European countries lead the race of per capita consumption, with Switzerland being in the first place with a consumption of 144.7 m2 per hundred inhabitants followed by Greece, Spain, Portugal, Belgium and Italy. On the other hand, during the period 2001-2002 the generated stone wastes were 110 million tones according to EU data, from which only about 5 million tones were recycled or re-used mainly in the construction industry. These stone wastes the non-natural wastes such as oils or chemicals coming from the equipment and machinery employed for stone extraction and processing, are disposed in the environment, posing serious environmental threat. To achieve sustainable development of the stone sector appropriate methods that will prevent or reduce waste generation and disposal have to be identified and applied. In this work an extensive study of the stone waste management techniques applied in Europe is carried out, in order to identify the Best Available Techniques (BAT) that can be used according to the type of generated wastes and the waste management hierarchy: Waste minimisation, Re-use, Recycling and Disposal. The identification of BAT was performed based on 14 Sustainable Development Indicators (SDI), which were grouped into three categories: environmental, economic and social. The developed final list of BAT includes waste minimisation techniques, eco-management schemes, in-situ treatment and appropriate storage and selection.

Jan 1, 2007