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By JIACHENG XIE, XUEWEN WANG, QINGBAO BAO, ZEWEN YAN

The general application of memory cutting technology to shearers is improving the intelligence of the working face, but it has its limitations. It is only suitable for conditions where the environment of coal seam is changing slowly. It compensates for the cutting height by changing the fuselage attitude, and frequently adjusts the height to control the learning cutting trajectory, but due to the problems of shearer control and height adjustment accuracy, it cannot adapt to and compensate for the change of cutting height in a timely manner, resulting in poor cutting accuracy. This study puts forward a virtual memory cutting method based on prediction of the shape of the armored face conveyor (AFC). The integrated key technologies include generation of virtual teaching cutting curve, height adjustment strategy of front and rear drums, cutting

By L. Widdifield, R. Riggle

"In today’s challenging mining environment the “Big Picture” (Caterpillar, 2013) approach to mining is often neglected. With haulage costs approaching up to 45 % of the overall mining costs, all too often the load-haul-dump- return cycle is not investigated in its completeness. This paper will discuss the aspects of taking the time to observe an operation from the “Big Picture” approach. In today’s mining business miners, engineers, trainers, supervisors, and managers have ever increasing roles and responsibilities as never seen before in the past decade. The endless human resource, safety, environmental, cost control issues and performance initiatives, detracts from precious time that may have been dedicated to examining the day to day operation. Having examined numerous mining operations over the past several years, one common denominator is lack of time to properly observe operating practices in the field and recognize both positive and negative observations. The old fashioned vocation of observing the operation to assess the haulage, loading and maintenance processes to adjust, maximize or enhance operations have sometimes vanished. Four areas to be discussed in this paper: (1) Look at the “Big Picture”(Caterpillar, 2013), (2) Use common sense, (3) Areas identified for biggest improvements in the operations, (4) Observation of small details for big impacts to lower cost per ton and increased production. The objective of this paper is to provide low cost recommendations to lower cost per ton and increase production. INTRODUCTION Whether miners claim to have been around and experienced it all or the “rookie” on the mine site, miners are expected to execute the mine plan at the lowest cost possible. So why is it so difficult to execute this task? Shouldn’t supervisors just have to man the equipment, tell operators to have a safe day and tally up the numbers at the end of the shift? And let the technology system do the rest? So what could go wrong? Lots. Mining companies seek help from consultants, training departments, performance reporting systems and an arsenal of resources. Armed with all this information, the supervisors just hop in the pick-up and tell the shovel operator to speed up. Sounds simple enough. When the improvements don’t happen, what could have gone wrong? It comes down to people, the simple things that were not executed over the months previously and as a result today the mines performance is not where it should be. A mine is built by people. Managers who have the vision to develop the ore body in a manner that follows sound engineering practices. The infrastructure to mill the ore and support the equipment needed to move the material. Along the way equipment is procured and operators trained to run the gear. Engineers and geologists set up the design, the material movement, and haulage routes. Sounds easy to this point. So, why mine after mine is there this constant struggle to move more with less and get the costs down? Understanding how to make “Great Miners” out of these people is critical to lowering your cost per ton."

Jan 1, 2016

By R. K. Young

Producing a sound plant design for a major project requires hundreds of engineers and many drawings. Economical accomplishment of this task is based upon careful and orderly organization of the design team so that at all times there is a complete and workable staff but at no time a surplus of costly talent. This paper will describe the various stages in the development of plant design which normally follow the laboratory and pilot plant investigations discussed in other papers today. An outline of the procedures used in the assembling of a project design group, within an established engineering organization will be presented. Actual procedures may vary according to the size and character of the plant, the special requirements of the owner, and the make-up of the engineering organization performing the design, but most of the points covered will be found to be basic to any plant design project.

Jan 1, 1960

By Ajit Godbole, Ping Chang, Ramakrishna Morla, Purushotham Tukkaraja, Shivakumar Karekal

This paper presents the results of a study on the optimum auxiliary fan location to control air recirculation in dead-end workings where diesel-powered vehicles operate. Investigations were conducted with various secondary fan locations from the dead-end crosscut and with the intake air quantities varied using different auxiliary fans to control air recirculation and diesel particulate matter (DPM).

Jul 1, 2023

By L. Galarza

"INTRODUCTION Beneficiation of ores and minerals in a concentrator plant requires a significant amount of water [1] for the grinding and particle separation processes; most of it ends up being recirculated for reuse, slurry pumps are used after crushing and grinding feeding the ore to a classifier to separate fine-grained material (less than 5 mm) from coarse-grained material requiring further grinding. The lower ore grades [2] in the past couple of decades have demanded an increase on power size and efficiency of process machines to maintain a competitive plant throughput; Hydro-cyclone feed pumps to control both under and over milling or grinding are not the exception; Fig. 1 shows a conventional drive train [3] comprising an (1) asynchronous motor (also known as squirrel cage induction motor = SCIM), a high speed coupling (2), a gear reducer (3) and a low speed coupling (4) attached to the shaft of the pump (5), to accommodate the motor rated speed (typically 1800 rpm) to the process requirements (in the range of 250 rpm to 350 rpm), requiring additional components related to the gearbox: instrumentation, maintenance, disposable lubricants and filters, spare parts, thus reduces the overall system efficiency ultimately reflected into CAPEX and OPEX.WHY VARIABLE SPEED DRIVES FOR CYCLONE FEED PUMPS Hydrocyclones or commonly referred as “cyclones” are one of the most important devices in the minerals industry [4]; almost universally used in close-circuit grinding because of their high capacity and relative efficiency, the evolution of Power Electronics made affordable the use of Medium Voltage - Variable Frequency Converters (VFC) for Cyclone Feed pumps in combination with induction motors larger than 500hp (373kW) to gain multiple benefits: - Soft start with minimum electrical utility disturbance = inrush current mitigation - Full Torque available at zero speed for overload startup with pulp solidification after long still stand periods, superior to any other reduced voltage starting method. - Optimum and constant pump speed (independent of the electrical network or load condition), compared to across the line SCIM operation - Flexible Motor Voltage and Speed regardless of the power distribution Voltage and Frequency - Improved Power Factor (close to unitary), over the entire operating speed range"

Jan 1, 2015

By W. Rocher

The Minera Ojos Del Salado (?MINOSAL?) concentrator is located 20 kilometers southeast of Copiapo, Chile and processes copper ore provided by its Santos and Resguardo mines at a capacity of 4,200 tip (4,620 stpd). Phelps Dodge acquired the majority interest in MINOSAL in 1982. The principal incentive for this purchase was the exploration potential of the property. At that time, the concentrator plant was a small, antiquated installation with a capacity of 674 t/d (740 stpd). In 1982, the majority of the ore was produced from the Santos and Resguardo mines, but custom ores of copper, silver, and gold were also treated. The acquisition occurred at a crucial time in the copper business, since the price had fallen to nearly $0.50 per pound. In 1985, Phelps Dodge purchased the outstanding interest in MINOSAL and acquired 100% of the property. Today, after numerous improvements and two expansion projects, the concentrator is an interesting combination of old and new equipment. The regrind mills, for example, have been in service for about 50 years, while the ceramic concentrate filter represents the latest technology.

Jan 1, 1993

By Trent A. Tempel

In 1989 Newmont Gold company initiated a project to develop a treatment process for higher grade refractory gold ores to be mined from deposits along the Carlin Trend in Nevada. Extensive laboratory and pilot testing have identified a unique whole ore roasting process for oxidizing these ores prior to gold recovery by conventional cyanidation techniques. Subsequent detailed engineering studies by Fluor Daniel evaluated three different dry grinding flowsheets for feed preparation to this roasting circuit. The selected flowsheet will incorporate a two compartment ball mill with an attached drying chamber that is driven by a 11.2 MW (15,000 hp) wrap-around motor.

Jan 1, 1993

By B. C. Lewis

The mining industry has experienced a general trend toward an increasing number of longwall operations, an increasing percentage of underground coal being mined by longwalls, and increasing productivity from the longwalls. Longwall operators have not yet reached a state of mining euphoria. Competitiveness both within the industry and from alternate fuel sources is forcing continued pursuit of higher productivities and lower costs. The following graphics present trends in the industry. Longwall mines, as defined for this presentation, are those reportedly having longwall installations in each of the respective years. Production from both the continuous miner and longwall units is included in the longwall mines. Non-Longwall mines are all other underground mines. Productivity calculations are based on total employee-hours associated with the operation.

Jan 1, 1990

By Firat Atalay

Estimating the spatial distribution of ore grade is one of the most critical steps to proceed with an investment decision on a deposit. Kriging is the most widely used method to estimate the ore grade, but alternative techniques are being developed. Machine learning algorithms can be used as alternative methods to classical kriging. In this paper, the iron (Fe) grade of a deposit is estimated with the XGBoost algorithm, and the results are compared with kriging estimation results. For the estimations, samples collected from drillholes were used. Due to the different natures of the estimation methods, different steps were taken to perform the estimations. The results show that XGBoost produced higher-range estimates, which is a desired result in ore grade estimation, and the minimum and maximum of the estimates were lower and higher than the kriging estimates, respectively. However, like kriging, the estimation results were smoother than composites, and the variance of the XGBoost estimates was lower than the variance of composites. This means that even though estimation with XGBoost mitigates the smoothing effect, the estimation results suffer from smoothing like kriging.

Dec 1, 2024

By M. Rotz

In the minerals industry today, the ?low hanging fruit? that once existed to debottleneck production and improve recovery, while meeting market needs for quality in mineral processing operations, are more and more difficult to find. Systematic methods for establishing plant mass flow, recovery, operational efficiency and control strategy in context with customer specifications provides the necessary insight and confidence for plant operators to prioritize improvement projects in order to maximize return on investment (ROI) for the site. The evaluation of aggregate and industrial mineral processing plants requires the following steps when projecting cost saving opportunities: collecting background data, conducting a base-line evaluation, analyzing specific unit-operation performance, defining investment options, prioritizing the selected improvement opportunities and the implementing process changes. The following paper describes the approach and challenges of developing an improvement plan for a dry and wet mineral processing operation.

Feb 23, 2014

By P. W. Erickson

Development of the Twin Buttes mine entailed the largest known preproduction stripping job in the history of mining. It linked earthmovers and conveyor belts in a new approach to development of a pit that may reach, or even exceed, dimensions of 1 x 1-1/2 miles at the surface and go as deep as 1800 feet. The orebody to be stripped was covered by an average of 460 feet of alluvial gravels, which presented an initial stripping job of great magnitude. The initial pit layout and the original time schedule established early in 1965 called for the excavation and disposal of about 250,000,000 tons of alluvial overburden before the end of 1969. Allowing about a year for equipment delivery, this schedule left four years to do the job averaging about 62-1/2 million tons per year. In 1964 when The Anaconda Company undertook the development of Twin Buttes, it was recognized that special planning was necessary for the disposal of waste material and tailings. Environ- mental control was a prime consideration and is particularly sensitive in the Twin Buttes area due to the proximity to residential developments. Disposal of the 250,000,000 tons of alluvium, as well as future rock and tailing waste material, presented a problem which Anaconda engineers resolved by designing a plan to spread out much of the alluvium over an extended area, including a massive 11- 1/2 mile dike system which will impound mill tailing in three basins. The tailing will be impounded behind these-dikes to avoid wind exposure and blowing. The dikes also serve as a

Jan 1, 1974

By Charles E. Mauk

In 1970, recognizing the great need for an economical, high capacity chemical oxidation process for wastewater treatment, Houston Research began a fundamental study of the available technology, Included was waste characterization; oxidation chemistry for molecular oxygen, ozone and catalyst initiators; kinetics of reaction; gas-liquid contacting methods; and optimization of staged reactors for mixed wastes. Although ozone is the most powerful oxidizer available, the literature contains contradictory reports of its speed and effectiveness. It is now felt to be most likely that many of these early investigations were limited by the ineffectual transfer of ozone from the gas phase into the liquid, and so the investigators were really observing the effects of mass transfer and erroneously trying to interpret the results as if they were chemical reaction data. HR's work considered the cost and effectiveness of gas-liquid contacting in a packed tower, gas sparged contactor, ejector with hold-up tank, and a completely mixed, sparged contactor. The sparged, mixed contactor was found to be most effective and least expensive, and a later investigation settled on the reactor configuration shown in Figure 1 because of its effectiveness of mass transfer and because it lends itself to direct scale-up techniques using laboratory data to design larger reactors.

Jan 1, 1975

By Collin L. Stewart

Published subsidence data for the western United States is limited in comparison with data for the east. This paper summarizes the results of a subsidence monitoring program above two longwall panels at the Foidel Creek Mine located in northwest Colorado. The monitoring area is characterized by overburden ranging from 1000 ft to 1100 ft in thickness. The surface slope parallels the dip of the bedding at approximately 5 deg. Average mining height is 9 ft. Smax averaged 3.4 ft. Draw angles averaged 15 deg for up-dip ribsides and 19 deg for down-dip ribsides. A site-specific profile function is developed from the data.

Jan 1, 1986

By Siddhartha Agarwal

The mining industry collects a significant amount of operational data. However, gleaning useful information from the terabytes of data is difficult, and not just because of the sheer volume of the data. Therefore, an automated tool was developed at the University of Alaska Fairbanks to go through data and apply sophisticated statistical and neural network techniques in order to identify the data streams that are important to a process. This paper presents results from the tool as applied to SAG mill data from a gold mine. The results were compared to results achieved earlier with available commercial modeling tools. The comparison indicates that there was little or no loss in performance by automating the very complicated process of neural network modeling. Therefore, the intent of the exercise, to examine if complicated modeling tasks can be automated, was realized. Mining Engineering, 2011, Vol. 63, No. 12, pp. 52-54. Official publication of the Society for mining, metallurgy and exploration, Inc.

Jan 1, 2011

By A. J. S. Spearing, A. Mueller

The support of intersections in coal mines remains an important safety issue, mainly because the large diagonal span compromises the stability of the roof. This structural weakness is further exacerbated if the intersection is developed incorrectly, the pillar corners fail or the crosscuts are angled (not perpendicular). This report details the current support systems used and investigates unplanned falls of ground in intersections in coal mines throughout the United States. A possible failure mechanism is proposed and some suggestions are made to improve the effectiveness of the support in these vital areas.

Jan 1, 2009

By J. A. Bartnik

Flocculation, the process of coagulation or coalescence of finely divided particles, is commonly used in separating fine solids from fluids. Forces disposing of the particles to flocculate include: ionic forces of attraction, secondary entropic forces, and magnetism. Magnetic flocculation is due to a physical magnetizing process which affects suspended ferromagnetic particles. Such particles, after exposure to magnetic fields strong enough to cause reorientation of the particles and alignment of the induced magnetic poles, tend strongly to retain this induced magnetism, as the magnetic retentivity of ferromagnetic particles is a linear function of its specific surface.1 Thus, because they become small magnets with high residual magnetism, the particles become and remain attracted to one another, forming large agglomerates. Fine magnetic particles close to domain size can exhibit energies of the magnetization of the order of 105 ergs/cm3,2 which is many times greater than the energy affected by chemical flocculents. Therefore magnetic flocculation can be used to agglomerate particles having surfaces ionized with like charges and only a minute quantity of ferromagnetic material will be necessary to develop sufficient force to overcome the repulsive ionic forces and hold together relatively large masses of fine solid agglomerates suspended in fluids. Since flocculation occurs after the fine suspension passes through a magnetic field generated by magnets surrounding a pipe section, the simplicity of the process and economic advantage makes magnetic flocculation very attractive.

Jan 1, 1971

By F. K. Spragins

The growing demand and a diminishing supply of conventional crude oil in North America are bringing about an ever increasing interest in the so-called "synthetic fuels". With one commercial plant already in full production, another in the planning and engineering stage, and still others being seriously considered, the Athabasca tar sands is proving to be a leading center of interest. Here, and in the closely related deposits, reserves in place total over 700 billion barrels.1 This major source of new oil is about ready to play a significant role in the filling of ever increasing market demand. When and if fully developed, the Athabasca tat sands could make both Canada and the United States substantially independent of all off-shore supplies of crude for many years to come. Its product, a high-quality, low-sulphur synthetic crude, is beginning to enter the market place at a most favourable time.

Jan 1, 1972

By C. R. Kuhn

From 1968 to 1975, most work in surface modification of inorganic materials involved silane coupling agents. A silane coupling agent can be described simply as an oganosilicon chemical having a general formula RSi-X3 wherein the R group is attached to a silicon in a thermally and hydrolytically stable manner, and X is a hydrolyzable group usually having an alkoxy functionality. About 1975, Kenrich Petrochemicals brought into the market place titanate coupling agents. Titanate coupling agents usually consist of one alkoxy group and three functional groups attached to a central titanium atom. Zircoaluminates became available in about 1982. Zircoaluminate organometallic coupling agents, which vary principally in their respective organofunctionalities, arise from a basic technology in which two different types of organic ligands are selectively bound to a low-molecular weight zircoaluminate backbone.

Jan 1, 1995

By L. J. Tucker

The magnetite orebody at Pea Ridge strikes NE-SH and dips at about 800 to the SE. The ore is high grade magnetite with a strike length of over 600-m and a maximum width of over 180-m on some of the levels. The shape and the mineral content of the iron orebody have been fairly consistent so far. The iron ore and surrounding basement rocks are Precambrian in age. These rocks are usually very competent, about 400-m of sediments lie over the ore.

Jan 1, 1991

By Ehsan Alavi, Eren Kusdogan

The City of Toronto’s Coxwell Bypass Tunnel is currently being constructed by North Tunnel Constructors ULC, a joint venture of Jay Dee Canada, C&M McNally Tunnel Constructors and Michels Canada. This project includes construction of approximately 10.5 km of 6.3 meter finished diameter rock tunnel, five 20 meter diameter storage shafts and eleven tunnel connection drop shafts, along with associated deaeration and adit tunnels. This paper describes progress on the project to date and reviews the risk mitigation measures utilized on the project to move the project forward through tough geological conditions during shaft excavation and tunneling phase of the project.

Jun 13, 2023