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By E. A. Córdova

Current methods for scratching a piece of rock to obtain or check the characteristics of its component material can sometimes be expensive and time consuming. Scratching a rock core requires an object with a point that it is capable of sliding along the surface of the rock while recording the response from the rock due to the sliding. With the idea of providing a cost efficient solution for a scratch device, a new generation turntable arm, composed of a cartridge with a diamond stylus and a USB output connection to the computer, was used to record the vibrations from the sliding of the stylus along a rock core surface. The output sound from the stylus was captured with the computer as an audio input signal. The raw sound data was recorded in a standard waveform audio format (wav) file, and post-processed using sound spectrum analyzer software (Spectra-Lab) to capture numerical data such as frequency, amplitude, and noise from the file. The results for frequency, amplitude, and noise were compared and plotted against the scanned surface of the rock core in the search for correlations that might represent specific characteristics of the surface being scratched.

Jan 1, 2010

By Guy Bridges, Elton Ko, Cheng Ting Ning, Owen Ng, Giovanni Chang, Robert Anderson

"PROJECT OVERVIEWThe Liantang/Heung Yuen Wai Boundary Control Point (BCP) and Associated Works will be the seventhland crossing between Shenzhen and the Hong Kong Special Administrative Region (HKSAR) of China.The project includes site formation of about 23 hectares of land for the development of the BCP and anapproximately 11-kilometre (km) long dual two-lane trunk road (the “Connecting Road”), connecting theBCP with the existing Fanling Highway. The route alignment is within a relatively rural area of HongKong, with very limited similar infrastructure works carried out nearby. It passes beneath bothmountainous terrain, and alluvial plains, and falls within an area of several major regional faults andassociated metamorphism, resulting in a complex variety of ground conditions.ALIGNMENTThe Civil Engineering and Development Department of the Government of the Hong Kong SpecialAdministrative Region carried out extensive public engagement in selecting the alignment of theConnecting Road. Over 70 consultation forums with public bodies, including the District Councils, RuralCommittees, local representatives, etc. were held during the alignment design process. In order toalleviate the concerns of various nearby villages, and to minimize land clearance and environmentalproblems, the original alignment of 10 km long (3.5 km of tunnels and 6.5 km of viaducts) was revised toits final alignment of 11 km long which comprises 5.7 km of tunnels, 4.3 km of viaducts and 1.0 km of atgrade roads.The finally adopted alignment commences at the southern end with an interchange with the existingFanling Highway, part of Route 9, which is a dual three lane expressway currently being widened to dual4 lane. Alongside the expressway is the main rail connection to the mainland of China, and theinterchange viaducts connecting to the southern portal of the Lung Shan tunnel must cross over thisrailway. The southern portal is located in the foothills of Lung Shan, and the 4.8km long tunnel is alignedin a north-northeasterly direction. The southern half passes under mountainous terrain of Lung Shan,and then crosses a valley containing the Kwan Tei river. The northern section comprises low hillsseparated by an alluvial plain and Tan Chuk Hang village area. At the northern end, the tunnel turns tothe north-west to connect with Sha Tau Kok road, an existing single carriageway road, with a newroundabout interchange. Mid-way along this tunnel there will be a ventilation building, connected to the main tunnel by a 330m long ventilation adit. To the north-western side of this interchange is the900m long Cheung Shan tunnel, and after this the remaining 4.3km of the highway connecting with theBoundary Control Point is to be constructed as an elevated viaduct. The alignment is shown in Figure 1."

Jan 1, 2016

By Kotaro Ohga, Kiyoshi Higuchi

In our laboratory, a new detection system using smell detectors was developed to detect the spontaneous combustion of coal and the combustion of other materials used underground. Laboratory experiments were carried out on several kinds of coals, including South African coals, and machine oil, wood and rubber used in belt conveyers. The following results were obtained: 1) Spontaneous combustion of coal can be detected earlier by smell detectors than by conventional CO detection methods. 2) There were no differences in the results using different kinds of coal. 3) Combustion of other materials can also be detected earlier by this system than by conventional detectors for gas and smoke. 4) Use of this detection system enables one to discern the source of the combustion gases, whether it be coal, wood, oil or rubber.

Jan 1, 1995

By BARBOSA AMILTON, Denise C. R. Espinosa, David B. Dreisinger

Chelating resins can be used to recover important metals from different sources, and it is important to understand which resin is most suitable for each metal [1]. This review  benefits the mining industry because chelating resins can be used to recover metals from low-grade ores and mining tailings, increasing the industrial process efficiency [2–4]. Furthermore, the use of chelating resins in mining processes and mining tailings has the common problem of metals contamination, with iron being the main contaminant in low-grade ores and tailings. Understanding how contaminants decrease ion exchange efficiency is significant for industries [5

By Clark B. Risler

Conveyors constitute a critical artery, essential to the successful operation of most ore processing plants. Technological progress is permitting the recovery of metal from low grade ores which previously could not be worked economically. Significant in this progress are improved material handling techniques highlighted by the frequent and successful application of conveyors. From the standpoint of the plant manager the successful conveyors are those he never hears about. They continue to economically transport the loads applied to them, requiring only routine maintenance attention. When such conveyors are subjected to closer scrutiny you will find that they have been carefully selected and engineered to perform the required function under the anticipated conditions. Among the primary elements in a conveyor drive are the electrical motor and the speed reducer. The selection of these elements can be aided by the systematic consideration of several factors. These factors which focus attention on the critical operating conditions, will be individually evaluated and their effect upon the selection of the electrical drive system and speed reducer analyzed.

Jan 1, 1958

By Edward K. Davison

The so-called "construction aggregates," sand and gravel, crushed stone, and several kinds of metallurgical slags, are used principally in the construction and maintenance of all kinds of roads, engineering structures, buildings, homes, airports, etc. Production of these aggregates is approaching two billion tons annually. In terms of tonnage produced, sand and gravel has been the leading mineral since 1954, with crushed stone gradually approaching an equal tonnage. Sand and gravel is of widespread occurrence and of wide variation in suitable gradation and quality. It is a low-value, heavy-loading, short-haul commodity. These characteristics account for the historic concentration of production tonnage in and near urban areas where construction activities are concentrated. The combination of improved urban and near-urban highway systems and the steadily rising rail rates for short-haul traffic has fostered a consistent change since World War II from rail to truck transport, with trucks now accounting for more than 807 of the tonnage moving away from the production sites. While there are increasing numbers of exceptions, truck transport of sand and gravel is generally limited to about 30 miles. The expansion of the urban and near-urban areas of even moderate density, which became so pronounced after World War II, has been the source of most of the sand and gravel industry's environmental difficulties. Dust, noise and truck traffic associated with the operations -- particularly truck traffic -- have, of course, generated public complaint. This has been particularly true in those many cases where housing developments have approached and even surrounded sand and gravel operations which were in operation before the development started.

Jan 1, 1974

"Iron ore is the source of primary iron for the world’s iron and steel industries. Its production can be reported as crude ore, usable ore or iron content of ore. Historically, the U.S. Geological Survey (USGS) used reported crude ore production from China in tabulations of world iron ore production while other countries have typically reported their production in terms of usable iron ore. When China’s crude ore production was tabulated with usable ore production from other countries, world iron ore production totals have been overestimated by 10 percent to a high of content and may include products such as concentrates, direct-shipping ore, pellets, and sinter.• Iron content, also referred to as metal content or grade, denotes the amount of elemental iron in the crude or usable ore.BackgroundIron ores consumed in the steel industry typically require an iron content greater than 58 percent before being considered commercially usable. Iron ores that are not commercially usable must undergo beneficiation to raise the iron content. Approximately 98 percent of the world’s usable iron ore production is consumed in blast furnaces to make pig iron, which is further processed to make steel.High-grade iron ore mines can supply usable iron ore, known as direct-shipping ore, to blast furnaces, with minimal physical processing and no beneficiation. With direct-shipping ore, the reported production for crude ore and usable ore are the same. Ore from low-grade deposits must undergo beneficiation to increase the iron content before it can be used by the steel industry. In this instance, the mined material is called crude ore and post-beneficiation concentrates are called usable ore; the amount produced will be less than the crude ore amount. With the notable exceptions of countries such as Australia and Brazil, most of the world’s iron ore deposits are low-grade and require beneficiation."

Feb 1, 2017

By D. M. Larsen, K. R. Gardner, P. B. Altringer

The Bureau of Mines, U.S. Department of the Interior, is conducting batch and small- scale continuous laboratory studies on the biologically assisted removal of selenium from process waste waters. Mixed cultures of gram- negative bacteria isolated from several brackish water marshes are capable of reducing selenate [Se(VI)I to selenite [Se(IV)I and precipitating an amorphous elemental selenium product. Selenium extractions ranged from 80 to 96% regardless of the initial selenium concentration. The conditions for rapid bacterial growth and reactor design for optimal selenium removal have been investigated. The mechanisms of bacterial reduction and the rate of selenium removal for scaleup to larger systems is discussed.

Jan 1, 1989

By William E. Foreman

Editor's Note: For purposes of uniformity throughout this book, Coal Preparation, 5th Edition, the editors have advocated the use of the U.S.A. Sieve Series of testing sieves (see Table 6-2) as the testing sieves of modem choice. The adoption and use of the U.S.A. Sieve Series and its forerunner, the Tyler Standard Screen Scale, has for over seventy-five years introduced uniformity into reports; has simplified the comparison of results; and has provided control for operation of modem coal preparation circuits. While a full explanation of the differences, and more importantly the similarities of these two measuring systems cannot be stated here, it is felt that a brief clarification of terms is in order. The difference between the U.S.A. Sieve Series and the Tyler Standard Screen Scale Sieve Series is the identification method. Tyler Screen Scale sieves are identified by mesh designation with the width of opening varying by the square root of two, or 1.414 times the width of opening in the previous sieve. The U.S.A. Sieves are identified by openings in millimeters or microns and also arbitrary numbers which do not necessarily mean the mesh count; this series uses width of opening variations in the order of approximately the ratio of the fourth root of two, or 1.189. Tyler Standard Screen Scale and U.S.A. Sieves can be used interchangeably, and to avoid confusion the nameplate of all Tyler Screen Scale sieves show the U.S.A. Number, while all U.S.A. Sieves show Tyler Screen Scale mesh equivalent numbers on the nameplate. INTRODUCTION Sizing is the process of separating mixed mineral particles into groups of particles all of the same size, or into groups in which all particles range between definite maximum and minimum sizes. This chapter applies the modem mechanical screen and the liquid-solid cyclone (hydrocyclone) to the process of sizing solid particles as applied to coal preparation. Screening is a mechanical process that separates particles by size. Modem coal preparation is made possible by efficient sizing. Sizing of coal is defined in terms of the opening through which an individual particle will or will not pass, or as two openings, the larger of which passes the particle and the smaller of which retains the particle. Screening accomplishes sizing by passing coal of a wide range of sizes through a series of screens, each of a decreasing size. The individual screen discharges are then directed into different screen products for subsequent sale or processing. Screening in modem preparation plants is done for the following reasons: 1. Removal of fine coal before a size reduction step. 2. Size separation of the coal into a coarse and fine fraction for sized products or for processing in coarse and fine coal circuits. 3. Recovery of heavy media from heavy media coal cleaning circuits.

Jan 1, 1991

By D. D. Young

During the 1970's a number of covered storage facilities were constructed in North America to store and handle large quantities of bulk, solid materials. This trend, away from outdoor storage piles, will probably continue at a stronger pace in the 1980's. This paper attempts to answer some of the questions often raised about the economics of large covered storage facilities. The paper is in four parts: 1. Why Build a Storage Facility? 2. 2. Common Components of Storage Systems With Details of Six Storage Facilities 3. Results of a Study for 50,000 Mg Clinker Storage 4. Guidelines for Conducting a Study to Select a Storage System.

Jan 1, 1980

By S. A. Pirzada

A thermal plasma assisted laminar flow reactor has been used to evaluate the kinetics of converting alumina to sodium aluminate in flight. Free energy minimization calculations were used to determine experimental conditions. The experimental variables include: alumina particle size, alumina/sodium nitrate molar ratio, temperature and residence time. A mathematical model for the conversion was developed and validated. Experimental and mathematical results are presented.

Jan 1, 1996

By H. L. Ford

Flocculant testing should be initiated for economic or performance reasons. When the decision has been made to test, the laboratory can provide valuable information concerning the various products under consideration. Properly conducted laboratory tests can determine: 1. If two flocculants are needed to achieve clarity or density. 2. Ease of mixing. 3. How quickly the material goes into solution. 4. Stability of prepared f locculant solution. 5. Stability of the floc formed. 6. Amount of mixing required for proper floe formation. 7. Optimum flocculant concentration. 8. Optimum pulp density. 9. Approximate location of the point of addition. 10. Single or multiple addition points. When a flocculant shows promise in the laboratory, a plant test should be scheduled. During the plant trial, arrange for normal conditions and start testing with a crew that is most familiar with the unit operation where the flocculant will be applied.

Jan 1, 1986

By R. K. Mehta, S. K. Dhar, R. R. Mallepali

Introduction The incentives for developing a distributed form of the comminution model include: • for describing the heterogeneous comminution behavior of multiphase mineral systems (i.e. realistic ore bodies, such as complex sulfide ores consisting of chalcopyrite, galena, sphalerite, pyrite and siliceous minerals) and •for generating, for various locked and free particles, in situ, microscopic, breakage behavior such as the mode of fracture (intergranular vs. transgranular), the relative rates of breakage and the breakage distribution. However, the computational difficulty and the effort made in estimating a large number of parameters (Andrews and Mika, 1975; Wiegel, 1976; Herbst et al., 1985, 1988) do not justify the utility of this approach. Also, obtaining the results experimentally is very tedious and time consuming if using this approach. Although recent work in this area (Choi, Adel and Yoon, 1987; Mehta, Adel and Yoon, 1989, 1990) showed good results for liberated particles, the quality of the estimation and prediction was poor for locked particles. Attributing this to the complex breakage behavior of locked particles, it was concluded that additional constraints, and possibly modification in the breakage distribution functional form for locked particles, were necessary. However, further mathematical analysis revealed that the method previously used was in error. The purpose of this technical note is to present the correct solution methodology used in solving the general model equations of a multicomponent mineral system containing multiple classes of locked particles. Previous work and connection The general form of the comprehensive, distributed-component comminution model has been described as (Herbst et al., 1985) [d (m (0) -[ I - B ] S_ m(t) = A m(t) (1)] where [A] is the fundamental matrix/state companion matrix, commonly referred to, in the comminution literature, as the "mill matrix." Note that for a distributed-component comminution model, this is a full, general, real matrix, unlike a lower triangular matrix for a simple grinding model or a lumped-binary grinding model with one locked-particle class (Herbst et al., 1985, 1988). Also note that all of the underlined letters refer to matrices. Herbst et al. addressed the difficulty in arriving at a closed form of the analytical solution of Eq. (1) via similarity transformation [IT J inv (T)]]. This difficulty occurs for several reasons: •[A], as a general real matrix, may have complex eigenvalues and complex eigenvectors. •More importantly, there is no guarantee that a set of eigenvectors of [A] will turn out to be independent. An attempt was made to solve this problem by implementing a decomposition method. With this technique, the mill matrix was decomposed into a sum of lower and upper triangular matrices [(i.e., A = L + U)]. Then the solution was obtained using similarity transformation (Mehta, Adel and Yoon, 1989, 1990). [e(At) = e(L+U)t = e(Lt).e(Ut) _ [ TL Jt- (t) inv(T_L)] [-Tu Ju (t) inv(Tu)]] [But, unfortunately, e 1+U = e t . eu is true only for scalars and not for matrices (i.e., eL+u# eL- eU) unless they commute. In other words. eAt = e(L+u)t= ekt - eU' if LU = UL. Hence, this decomposition scheme must be replaced by a mathematically acceptable method known as the "splitting method"]

Jan 1, 1994

By A. Acar, E. T. Tuzcu, Y. O. Vural

"In order to sustain the operations in chromite processing plants, due to concentrate selling cost, plants are in need of optimization in terms of capacity and recovery increase. In this study, DAMA Engineering carried out a methodological study for the purpose after a detailed sampling campaign in a plant which is situated in one the main chromite zones in Turkey; 1 The current status of the plant was investigated quantitatively with the bottlenecks, Plant overall efficiency in terms of recovery, Efficiencies of the particular equipment (mill, screen, gravity circuit), 2 A new circuit was proposed with the available equipment, 3 The new circuit that is product of modeling and experimental effort, was evaluated quantitatively as if it is a running plant, After 4-5 months continuous effort, the capacity of the plant was almost doubled (37 tph to 70 tph) and the plant overall recovery was increased from 48% to 63% by grinding adjustments and additional shaking tables theoretically. It was shown that the plant may move into profit with the minimum amount investment using readily available system. INTRODUCTION TO THE CURRENT PLANT The objective of the study is to increase the capacity and recovery of the chromite plant owned by Kurmel Group, Akmetal Inc. The complete study is given elsewhere (DAMA, 2016). The plant is situated in one of the main chromite zones in Turkey; Aladag. The current capacity of the plant is around 35 tph and the overall recovery declared by plant engineer is around 47 %. The chromite plant mainly has 3 units; crushing, grinding and gravitational circuits. The crushing circuit has 3 stages; a jaw crusher, a secondary cone crusher and a tertiary cone crusher operating in closed circuit with a vibrating screen with the aperture size of 15mm. In grinding circuit, a rod mill (2.44 6m x 3.6) and a ball mill (2.13 x 2.3m) are used for primary and secondary grinding, respectively. Derrick screens are used for the size separation. Additionally, for the size classification of the system, hydrosizers are used and each size fraction is sent to the shaking table sets. The middling product of the tables is subjected to re-grinding with a ball mill with the dimensions of 2.1 x 2.9 m. The capacity and the recovery are affected by several bottle necks; hydrosizers’ pure classification, primary/secondary mill power vs capacity problems, re-grinding product’s high slime content and so on. These combined factors made the plant to run in low recovery and capacity. Hence, DAMA was asked to make a study to investigate current status of the plant and propose a new solution to increase capacity and recovery of the plant. The conceptual flowsheet of the circuit is given in Figure 1 below."

Jan 1, 2017

By R. J. Sweigard, R. V. Ramani

Three case studies were undertaken to investigate the role of land use potential evaluation in reclamation planning and to determine the impact of regional differences on final land use plans. The three surface mines studied were representative of operations in the Appalachian, Interior, and Northern Great Plains provinces. The scope of the investigations included a survey of regional characteristics, a detailed investigation of the mining operations and site conditions, and an assessment of local land use planning activities in the area of the mines. Special attention was given to key factors that presently determine the use of reclaimed land. Also, for each case study, the postmining land use potential was evaluated using site planning principles. Specifically, the environmental, economic, and social impacts of several potential postmining land use plans were considered.

Jan 1, 1987

By R. D. Hammett

This paper describes an investigation that MS carried out using the three-dimensional, stress analysis computer program "NFOLD" to assess pillar stability in relation to existing mining conditions and the proposed layout of future stopes. The stress analyses were designed to assess the present stability of the mine (particularly the pillars adjacent to the shaft), the change in pillar stresses as mining proceeds, and the optimum stope geometry to minimize ground control problems. The existing conditions were modelled first, and rock mass strengths were adjusted until a good agreement between the predicted and observed conditions was obtained. Analyses of alternative mining layouts, based on the calibrated rock mass strengths, were then compared. The paper describes the results and the conclusions of the study.

Jan 1, 1983

By B. Blaschuk

The Freeport McMoRan Bagdad Solvent Extraction (SX) circuit is the oldest plant of its kind currently in operation. The plant was commissioned in 1969 and was the second SX-EW operation to be built following the Ranchers Bluebird solvent extraction and electrowinning (SX-EW) plant near Miami, Arizona. Over the years of operation, the configuration of the SX has gone through many changes to accommodate a variety of pregnant leach solution (PLS) grades and flows. Although modifications to the original plant configuration are numerous, the Bagdad SX circuit has maintained its general form consisting of multiple long and narrow settlers. The unique configuration of the Bagdad SX circuit presents a variety of operational advantages and challenges; however, it continues to operate at a level recognized in the industry as excellent.

Jan 1, 2010

By Dennis A. Beiter, Kenneth G. Fields, Richard T. Stoltz

Section 56.5001 Title 30, [Code of Federal Regulations1], establishes requirements for respirable dust exposure in Metal and Nonmetal Mines based on the Threshold Limit Values (TLV's) adopted by the American Conference of Governmental Industrial Hygienists. Respirable dust samples collected by Mine Safety and Health Administration (MSHA) inspectors at a sandstone quarry showed certain workers were exposed to excessive concentrations during development of a "coyote tunnel" that was ventilated with a blowing system. Because exhausting face ventilation systems are known to control dust more effectively than blowing face systems, a change was proposed to improve worker respirable dust exposures. This paper describes the evaluation of the proposed exhausting ventilation system in the quarry's "coyote tunnel" and compares the respirable dust exposures with those measured by the MSHA inspectors with the blowing system. Results showed the proposed exhausting ventilation system reduced respirable dust exposures to less than 20 percent of those measured by MSHA inspectors when the blowing system was used.

Jan 1, 1993

By J. L. Arola

Since start-up of fluxed pellet production in August: 1987, the Minorca Mine has made a number of process changes to improve pellet quality and productivity. Quality improvements include: 1. Installation of a contraction t:ester. 2. Installation of on-line calcium and silica analyzers. 3. Process autocation changes. Productivity improvements include: 1. A second fluxstone storage bin and feeder. 2. A new vacuum pump and disc filter. 3. A filter aid addition system. 4. Enclosing the filter cake reclaim feeder. 5. A new grate bar cleaner.

Jan 1, 1989

By Ian P. G. Hutchison

12.1 INTRODUCTION This chapter deals with the tools required to design leach operations to minimize spillage from leach pads and ponds and erosion damage during flood events or prolonged wet periods. It outlines methods used to design for prolonged dry periods when water shortage can be a problem. Seasonal operational aspects such as winter shutdown and coping with spring snowmelt periods are also discussed. General criteria useful when designing pregnant and barren solution ponds are also outlined. The aim of these notes is to provide designers and operators with a simp1ified approach to developing design parameters which make effective surface water management easy to achieve without resorting to extensive or elaborate analyses. Section 12.2 briefly outlines the types of problems associated with wet climates and floods, as well as dry periods. Determination of flood design parameters is discussed in Section 12.3. Circuit water balance and pond sizing are outlined in Section 12.4. Pond design considerations are included in Section 12.5. Worked examples are included in Section 12.6. 12.2 RAINFALL/RUNOFF PROCESSES There are two types of rainfall-runoff processes that are important when designing heap leach facilities. The first of- these is the short-term, intense rainfall or snowmelt events that occur over a period of a few minutes or hours, causing flooding that can lead to erosion damage and overtopping of ponds and containment dikes. Specific problems that can manifest themselves during these events include: • Washout of access roads; • Damage to containment dikes; • Flood water contamination of circuit water; • Damage to process water ponds by perimeter erosion or overtopping and erosion; • Loss of process circuit fluid due to breaks in containment dikes or process water ponds; and • Erosion of leach pile and consequent sediment contamination of process fluid. Other types of rainfall -runoff processes that could cause problems are the long-term-(generally months-long) wet or dry periods. Extended wet periods

Jan 1, 1988