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By Hamed Khodadadi, Hamid Ghadiri

In this study, a fuzzy logic self-tuning PID controller based on an improved disturbance observer is designed for control of the ball mill grinding circuit. The ball mill grinding circuit has vast applications in the mining, metallurgy, chemistry, pharmacy, and research laboratories; however, this system has some challenges. The grinding circuit is a multivariable system in which the high interaction between loops, the variation of the system parameters with time, and time delay are some of the problems that pose a challenge. Since the controller parameters are determined offline in classic PID control, these gains are unchangeable and cannot overcome the mentioned challenges in this system. Hence, a fuzzy logic self-tuning PID controller, which is a combination of fuzzy logic and a conventional PID controller, is proposed to control the grinding system, especially in the presence of model mismatch and disturbances. In addition, in order to solve the system challenges, a multivariable control approach based on an improved disturbance observer is proposed to suppress the effects of the disturbances. The most important feature of the algorithm proposed in this paper as the combination of fuzzy logic self-tuning PID and improved disturbance observer is its ability to eliminate system interaction, attenuate internal and external disturbances, and compensate the effect of system uncertainty on the performance of the ball mill grinding circuit. Simulation results in the cases of the set-point change in particle size and circulating load in the presence of model mismatch and external disturbances confirmed the controller performance compared to other controllers.

By Hamed Khodadadi, Hamid Ghadiri

In this study, a fuzzy logic self-tuning PID controller based on an improved disturbance observer is designed for control of the ball mill grinding circuit. The ball mill grinding circuit has vast applications in the mining, metallurgy, chemistry, pharmacy, and research laboratories; however, this system has some challenges. The grinding circuit is a multivariable system in which the high interaction between loops, the variation of the system parameters with time, and time delay are some of the problems that pose a challenge. Since the controller parameters are determined offline in classic PID control, these gains are unchangeable and cannot overcome the mentioned challenges in this system. Hence, a fuzzy logic self-tuning PID controller, which is a combination of fuzzy logic and a conventional PID controller, is proposed to control the grinding system, especially in the presence of model mismatch and disturbances. In addition, in order to solve the system challenges, a multivariable control approach based on an improved disturbance observer is proposed to suppress the effects of the disturbances. The most important feature of the algorithm proposed in this paper as the combination of fuzzy logic self-tuning PID and improved disturbance observer is its ability to eliminate system interaction, attenuate internal and external disturbances, and compensate the effect of system uncertainty on the performance of the ball mill grinding circuit. Simulation results in the cases of the set-point change in particle size and circulating load in the presence of model mismatch and external disturbances confirmed the controller performance compared to other controllers.

By Ivo Dreiseitl, Kondratenko. Anatoly

"The second prime area within the Interoceanmetal Joint Organization exploration area named H22 was delineated in 2013 with the goal to ensure sufficient nodule reserves for profitable mining operations and processing.The knowledge base for area H22 has been obtained from archive materials. The geological situation can be characterized as follows: the sea bottom is represented by tectonic blocks oriented in a sub-meridional direction. According to swath mapping, the depressions (troughs) are contoured at depths of 4500-4600 m while the tops of horsts occur at 4300-4350 m. Volcanic relief occupies 6% of the H22 area; in the eastern part a multicone volcano was detected. Its area at the base is 153 km2. The maximum height of a cone above the base is 850 m. The crystalline basement composed by tholeiitic basalts of late Oligocene age is covered by about 100 m of sediments. Semi-consolidated to consolidated calcareous nanofossil sediments of the Marquesas formation are deposited on the basement. Higher up in the profile sediments of the Clipperton formation occur. They are represented by unconsolidated siliceous (Radiolaria, Diatom) ooze. Sediments containing calcium carbonate have not been detected. Where opaline silica (or CaCO3 if any) content is below 5%, the sediments belong to zeolitic clays or red pelagic clays. Grain size composition of the seabed and the near-seabed sediments in H22 classifies them into clayey silts."

Sep 1, 2014

By Nick Rose, Robert Sharon, Mark Rantapaa

Development of the Northeast Layback of Barrick’s Betze-Post open pit commenced in June 2000 and was successfully completed to a height of 400m (1,300 ft) in January 2003. Following a brief exploration drilling campaign at the toe of the final slope, in-pit waste rock backfilling commenced, which will ultimately buttress the final wall. Instability initially occurred in late 2000, above the 5040 Level, as the slope height approached 120m (400 ft). As mining reached the 4680 Level, significant deformation was experienced over a slope height of 230m (760 ft). Slope stability was managed and targeted reserve recovery was achieved by executing complicated modifications of the mine plan, including splitting layback development, well placed offloading cuts, step-outs and mid-slope waste rock buttresses. Decision on timing of these modifying events was often dictated by review of deformation magnitudes and rates determined from continuous slope monitoring records. Design modifications were developed through continuing interpretive refinement of structural geology controls and groundwater distribution, and through stability re-assessments. This document presents an overview of the geological setting and material and strength conditions of the northeast sector of the Betze-Post open pit, followed by development experience leading to design and development of the Northeast Layback. Rock mechanics modeling, design details and geotechnical performance monitoring are then presented. Development experience, stabilizing adjustments to the original design and safety procedures for development and exploration activities are described. The document is finalized with conclusions and acknowledgements.

Jan 1, 2005

By Robert M. Semple, Harvey W. Parker

INTRODUCTION Two promising innovative tunnel support systems are being developed by the Civil Engineering Department of the University of Illinois. One of these is a lining which can be placed by a slipform located immediately behind and contiguous with a tunneling machine. Recent advancements in construction materials appear to provide the breakthrough required to make such a system feasible and practical. The lining material which permits this construction scheme is wire fiber reinforced concrete made with high, very early strength regulated-set cement. Parts I and II of this paper relate to this slipformed liner. Part I discusses the material and equipment required to install the liner. The "Extruded Liner System" (ELS) has been devised to place the lining. This ELS concept is briefly described and a tentative development program is outlined. In Part II, the physical properties and practical construction aspects of the liner material are discussed and a program for structural testing of 10-ft diameter prototype tunnel supports is presented. Part III contains descriptions of improvements to conventional steel-rib tunnel supports. It is shown that square tubular box sections are structurally superior to wide flange sections for complex loading conditions often encountered in rock tunnels. Analytical studies and tests on connections have been performed to evaluate their structural behavior. These are presented along with a program for comparative large-scale tests on horseshoe-shaped frames with a 10-foot span. This research is being conducted by the Department of Civil

Jan 1, 1997

By Christian Neumann, Josef Arnold, Albin Reinhart

The Channel Tunnel Rail Link (CTRL) is the most significant railway infrastructure development project in the United Kingdom since the construction of the Channel Tunnel between France and England. The key element of this project is the 2-mile-long(3.2-km) North Downs Tunnel, which will be the largest and deepest twin-track railway tunnel ever constructed in the United Kingdom. This paper describes the contractual agreement, the design and construction (excavation and lining) of a twin-track rail tunnel with a 166-m 2 face excavated through chalk using the New Austrian Tunnelling Method (NATM). The importance of collaborating with a tunnel contractor/designer who not only is expert in the New Austrian Tunnelling Method, but who was also responsible for the design and installation of the primary lining, will be highlighted in this paper. This paper will also deal with the benefits of partnering in tunnel design and construction, as well as the resultant added values of mechanizing conventional tunnelling methods (Value Engineering).

Jan 1, 2001

By J. J. Gusek

There are hundreds of passive treatment systems accepting mining influenced water (MIW) throughout the world. Some systems do not perform to design expectations while others, including volunteer systems, have successfully operated relatively unattended for decades. The primary reasons for this situation include the common misconceptions that (1) a “cookbook” approach to design is valid for a wide array of MIW chemistries and site conditions, and (2) low maintenance means “no maintenance.” Passive treatment systems for MIW are typically manmade ecosystems that are designed to handle a specific range of metal loading conditions and MIW geochemistry. Thus, when design conditions are exceeded, the suite of microbial to macroscopic ecosystems may be slow to recover or mature. This should be no surprise to designers. But when a particular system fails, it may be inappropriately attributed to the technology, not the design. This paper presents a standard “phased” design protocol that appears to work and provides examples of sub-par performance of selected passive treatment systems.

Jan 1, 2002

By Amanda Elioff

Success of the Gold Line Eastside Extension rail tunnels in Los Angeles has prompted Metro?s planning for two new rail lines to include underground alternatives. The Westside Extension Transit Corridor alternatives include up to 17 miles of subway to be constructed in soft ground. The routes will require construction in Los Angeles? ?Potential Methane Zone,? not considered for subway construction until recently. Slurry face TBMs will likely be specified. The Regional Connector, through the downtown area, includes one underground alternative with 1.7 miles of tunnel as well as three underground stations in soft ground and rock. Challenges will include tunnel and station construction under narrow streets. This paper will describe the alternatives, planning, geologic conditions and tunneling concepts for both planning studies.

By Dermot Winters

The Surface Mining Control and Reclamation Act (SMCRA, or the Act) was enacted on August 3, 1977. The Act was written, in part, to put an end to uneven environmental standards and to establish minimum national standards. Certainly, one of the motivating factors for passage of the Act was the success of the Federal Coal Mining Health and Safety Act of 1969 in reducing deaths and injuries in the coal industry nationwide. Section 516 (b) (1) of the Act requires *that subsidence be prevented from causing material damage to the extent technologically and economically feasible except in those instances where the mining technology requires planned subsidence in a predictable and controlled manner. Section 516 (c) of the Act authorizes the regulatory authority to suspend underground mining if there is imminent danger to inhabitants of urbanized areas, cities, towns, and communities. On December 13, 1977, the interim program, which applies a portion of the performance standards of the Act, was promulgated. Then on September 18, 1978, the proposed permanent program was published for public comment. Finally, on March 13, 1979, the final permanent program was promulgated and the States were given a period of time to submit their programs for approval.

Jan 1, 1986

This paper investigates the effects of solids concentration and the addition of Dispersant S40 on the flowability of original and ground limestone slurries. A rotational viscometer with a concentric cylinder geometry and a controlled-stress rheometer with a cone-and-plate geometry were used to characterize the rheological behaviors of limestone slurries. The rheological behavior of original limestone slurries (<100 µm) is transformed through different types of flows with increasing solids concentration. The use of Dispersant S40 can improve the slurry flowability by decreasing viscosity and eliminating Casson yield stress. It is therefore used as a grinding aid for the wet ultrafine grinding of limestone. The rheological behaviors of ground limestone slurries vary with grinding from a starting dilatant flow-ability to a resulting pseudoplastic one with an evident Casson yield stress in combination with a thixotropic character. The appearance of pseudoplastic flowability combining thixotropy is related to the fineness of a ground product and its specific surface area, which are both correlated to solids concentration and the additive amount of Dispersant S40. In addition, the accurate rheological characterization of time-dependent fluids is dependent on the instruments used and operation conditions.

Jan 1, 2007

By S. H. Jason Choi

The Systems Conveyance and Operations Program (SCOP) is being implemented to convey tertiary-treated effluent to Lake Mead near Las Vegas, Nevada. The Reach 3 Tunnel Project is part of SCOP. The tunnel?s planned location along and across the Las Vegas Wash creates challenging tunneling conditions. A number of feasible excavation and initial support methods are being considered during the final design stage. This paper describes how the tunnel construction options were refined based on anticipated tunneling conditions and compatibility between tunnel excavation and initial support methods. A brief description of the most significant characteristics of the anticipated ground conditions is included for the purpose of discussion.

By N. I. Aziz, I. Tague, P. Mackenzie-Wood

The recent mine disasters in Australian coal mines have initiated an introduction of Self-Contained Self-Rescuer (SCSR) as component in the development of new escape strategies for miners. These self-contained self-rescuers are closed circuit, demand sensitive breathing apparatus that make oxygen available to the wearer for a nominal period of time. Their operation is completely independent of the surrounding atmosphere. Once properly donned, the SCSR can assist a miner to escape from an area containing smoke, toxic gases or an oxygen deficient atmosphere. The duration of a typical SCSR is usually taken at the point of complete collapse of the breathing bag which is accompanied by an increase in breathing resistance and inhaled levels of carbon dioxide. Because the oxygen consumption (V02) and the heart rate are correlated, a prediction of V02 and consequently the duration of an SCSR can be made by monitoring the heart rate. Thirty-seven volunteers participated in field simulated escape trials at four underground coal mines. The results from the field trials suggested that oxygen consumption depends on the heart rate, the body weight and exercise rating of the miner. All the volunteers were asked to fill out the questionnaires to evaluate the performance of the units. The miners indicated that they could tolerate the inhaled temperature without any difficulty to breathing resistance. A complete statistical analysis of the field results is also presented.

Feb 24, 1997

By Corby G. Anderson, Sheikh Abdul Rezan Sheikh Abdul Hamid, Sanjith Udayakumar, Ahmad Fauzi Mohd Noor, Teuku Andika Rama Putra

Chemical and mineralogical characterization of Malaysian monazite, a phosphate mineral, bearing rare earth elements separated from the tin tailings originated from Ipoh, Perak, Malaysia, was performed in this paper. The study aims to collect detailed information on the chemical composition, crystal phases, and microstructure of the mineral monazite concentrate that would aid to optimize the subsequent hydrometallurgical processes for high-efficient separation of thorium and other associated rare earth elements. A systematic characterization study of the concentrate was conducted using techniques such as optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). These techniques analyzed the morphological details on the surface, elemental analysis, and mineral association assessment and identified the surface functionalization groups. The bulk composition and the mineral phases in which the elements are present were studied by wavelength-dispersive X-ray fluorescence (WD-XRF) and X-ray diffraction (XRD) studies respectively. The XRF analysis confirmed the presence of Ce, La, Nd, Pr, and Y (rare earth oxides: REO’s ~ 60 wt.%) while thorium dioxide (ThO2) accounted for 7 wt.% of the total composition. Traces of Ca, K, Al, Fe, Ti, and Mn were also confirmed by SEM elemental mapping. The XRD results confirmed that the concentrate was primarily composed of monazite (Ce, La, Nd, Th (PO4)) along with minor impurity phases of quartz. Automated mineralogical analysis was used as a confirmatory tool to corroborate the preliminary evidences. Based on the particle size distribution analysis supported by SEM, the majority of monazite grains were found to be present in the size range of 170–210 μm. Strong bands of PO4 and SiO4 were observed in the IR spectra corresponding to the phospho-silicate matrix of the REE mineral.

By Wolfgang Roth

In 1990, a residential area above the North Outfall Sewer (NOS) tunnel constructed in 1924, experienced subsidence. After sewage was diverted into the North Outfall Replacement Sewer (NORS), soil probing from within the tunnel was conducted, soil-improvement options were developed, and a preferred grouting scheme was analyzed by numerical modeling to evaluate the stability of the 80-year+ old tunnel liner under grouting-induced loading conditions. This paper discusses the initial field investigation and the development and analysis of a grouting scheme originally intended to be implemented before relining of the tunnel. The scheme was later modified, and the new liner was installed before the final probing and grouting work was done.

Jan 1, 2008

By Christopher J. Bise

INTRODUCTION The principal means for transporting men, supplies, and mined material in an underground or surface mine are rail systems, conveyor belt systems, or a combination of the two. Typically, large underground mines use rail haulage from the mining sections to the hoist, with conveyor belts being used within the sections. Small mines use conveyor belts in the mains and sub- mains as well as in the panels. The size and layout of surface mines also contribute to variations in the way these haulage systems are applied. The following sections address the typical problems confronting mining engineers in designing these haul- age systems. For rail, these include rail selection and turnout design, locomotive tractive-effort calculation, and motor sizing. Belt haulage calculations include belt width and speed specifications, tension and take- up requirements, idler spacings, and motor sizing. TRACK LAYOUTS Introduction The adequacy of mine track layouts is dependent upon such factors as rail weight (Table l), suitable ties, a well-drained roadbed, and properly designed curves, grades, and track alignment. As long as the installation conforms to the manufacturer&apos;s recommendations, good service can be expected from the rail system. Typically, mining-engineering calculations for rack layouts have dealt almost exclusively with the design of turnouts. As such, the following section provides the necessary information for computing the theoretically correct dimensions of turnouts. Turnout Design Fig. 1 shows a typical turnout with an identification of the component parts. Fig. 2 identifies the variables that are used to determine the turnout dimensions. The formulas that concern the mining engineer are those listed: [ ]

Jan 1, 1986

By K. Oraee

Rate of penetration of Tunnel Boring Machines (TBM) has a significant role in the planning, measurement of productivity and performance of any tunneling project. In this paper, the application of Adaptive Neuro Fuzzy Inference System (ANFIS) in prediction of TBM penetration rate is evaluated. For this purpose, a database including Rock Quality Designation (RQD), Uni-axial Compressive Strength (UCS) of the rock, the Distance between Planes of Weakness (DPW) in the rock mass, and empirical data regarding rate of penetration of TBM from several tunneling projects are collected. The Rate of Penetration is then estimated by using ANFIS. These results are then compared with measured TBM penetration rates (actual data). It is concluded that ANFIS can be applied successfully for such purpose and result in high accuracy for prediction for the rate of penetration of TBM. The method provided in this paper can assist the mining engineer to estimate the performance of tunneling accurately.

Jan 1, 2012

By Garry Keizer

The Cortez gold mine is located in Lander County, NR, about 130 km (80 miles) southwest of Elko. Cortez Gold Mines (CGM) is a joint venture between Placer Dome US Inc. (60% operator) and Kennecott Corp. (40%). The claims that supply oxide and refractory ore feed to the Cortez milling facility are located in both Lander and Eureka counties. These include the Cortez and Horse Canyon deposits, all operated by the joint venture. Other deposits outside the CGM claim area include Fire Creek, Buckhorn, Gold Bar and Tonkin Springs. These deposits all occur along the Battle Mountain-Eureka Trend. History Mining in the Cortez district began in 1862 with the discovery of high-grade silver ores. Grades in the hundreds of ounces per ton occurred in an area 7 km (4.5 miles) southeast of the current CGM mill site. Underground mining through the Garrison and Arctic tunnels provided the bulk of the ore production between 1864 and 1895. To a lesser extent, the Mill Canyon area also supplied ore until 1930.

Jan 1, 1993

The minerals industry consumes billions of dollars in raw materials, equipment, tools, services and chemicals. The industry, though, has turned overmuch of the research and development (R&D) for these products to manufacturers and suppliers. Now the industry and its suppliers must decide how much R&D the mining industry should be responsible for and what role the suppliers should play. Promoting R&D As a result of the current environment in the mining and minerals industry, there has been a substantial decrease in R&D. Depressed prices, stagnant growth, cost cutting and rationalization are evident.

Jan 1, 2000

By Shimi Tzobery, Jay Davenport, Raymond Henn, Sam Bandimere

Over the past several decades, the use of cement-based grouts using ultra fine cement as a replacement for portland cement has begun to gain acceptance as an alternative to chemical solution grouts used in permeation grouting. The amount of information currently available on grouts made with ultrafine cement is limited. The authors used a previously developed field testing program to perform additional tests to evaluate the permeation performance of portland and ultrafine cement-based grouts. For the first time, the 2003 testing program included an attempt to determine the 28 day compressive strength of the sand permeated by the grout.

Jan 1, 2005

By T. A. E. Breen

A new high intensity grinding technology has been developed and is now being commercialized by Hicom International of Australia. This has led to the development and manufacture of Hicom 120 grinding mills which are now being sold internationally for a range of mining industry applications. The first commercial process application has been for the diamond sector, where the ability of the mill to remove host kimberlite rock by attritioning, with no damage to the thereby liberated diamonds, is seen to be a most beneficial attribute. There are, however, many other mineral industry applications for this mill. The design of the Hicom mill is unique. Based on a high speed centrifugal motion of the grinding chamber, very high power intensity is delivered to the grinding process. Most significantly, a high acceleration field, 50 times stronger than gravity is produced, creating very high power input per unit of mill volume, and exceptionally fast particle breakage rates, typically 50 - 100 times greater than those in conventional tumbling mills. A mill developing such forces has significant implications to comminution technology and practice.

Jan 1, 1999