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By Sebastian Avalos, Julian M. Ortiz

The long-term mine scheduling is the optimal decision on how to extract and process the mining reserves. The resulting plan is mainly driven by economic, metallurgical, and geological factors. Accounting for their uncertainties leads to a robust solution and the feasibility for economic-risk quantification. In this work, we model the spatial uncertainty of grade distributions of multiple correlated elements, by using a multivariate morphing transformation. The result is a set of multivariate geostatistical realizations of the grades, which honor the conditioning data, the direct and cross variograms, and the multivariate statistical distribution, inferred from a set of samples. These models are the input in a reinforcement learning framework, adopted to train a deep neural network that considers the grade uncertainty and leads to an optimum mine plan after training using deep Q-Learning. Mining and processing capacities, as well as economic parameters and metallurgical constraints, are incorporated as the reinforcement learning environment rules. The method is validated on a real deposit, providing insights for future applications.

Jun 25, 2023

By Cody Edwards, Ross Webb

5 miles of soft ground tunnel excavation for the SAWS W‑6 project finished months early despite difficult conditions. Success was achieved using TBMs and other equipment built long before most of the crew was even born. The old school means and methods easily adapted to the conditions encountered and were key to the project’s success. Unfortunately, an industry trend is to specify more “advanced” equipment which can sacrifice adaptability or productivity for a perceived reduction in risk. This case history discusses when traditional methods may be the best option.

Dec 1, 2022

By K. A. McDonald

This paper will describe the experiences of Hibernia Holdings, Inc. in constructing a mineral processing facility in Mexico. It will attempt to set forth a guideline on what companies attempting to operate in Mexico can expect and what actions they can take. Ownership laws, import/export laws, labor laws, security, transportation and operating experiences will be discussed.

Jan 1, 1994

By Cheng Ang, Yun Bai, Zhi Liu

"This paper presents a conceptual design of an innovative tunnelling method named the Ring Pipe Jacking Method (RPJ) which is conducted by the Ring Pipe Jacking Machine (RPJM). The RPJM consists of a double ring shell which forms a ring section where small interlaced cutter heads or several micro tunnelling machines are assembled to cut soil. Similar to the conventional pipe jacking method, the RPJM also needs a thrust system, a slurry transport system, and a control system. To satisfy the need for large/super large or special section tunnels in future, the RPJM is designed to reduce sharply the excavation face to the annular section, thus enhancing the face stability. Part of the innovation is that the RPJM uses modular cutter heads or micro-TBMs which can be reused. The typical double shield shape can be easily changed by reinstalling the modular cutter heads. Modularity allows the tunnel to be cut in any cross-section shapes, ranging from a circular tunnel to a rectangular one. INTRODUCTION The demand and requirement to utilize urban underground space is rising with the rapid social development in recent years. It is necessary to reduce excavations of the urban ground surface to ensure smooth traffic in cities. Therefore the conventional open cut construction method for underground tunnels can no longer satisfy the need of practical engineering, and it is taken over by trenchless technologies .The Pipe jacking method is an important trenchless technology and is used more and more frequently to install underground pipelines, but the present pipe jacking method still has many problems. For example, it is not suitable for installing large-diameter tunnels and it also has difficulty in construction of short radius curved tunnels. This paper presents a conceptual design of an innovative pipe jacking machine named the Ring Pipe Jacking machine (RPJM) and introduces the correspondent Ring Pipe Jacking Method (RPJ) which can be applied to construct large-diameter tunnels. Furthermore, technical characteristics and superiority of the ring pipe jacking method are analyzed in this paper."

Jan 1, 2016

By Andrew J. Neale, Chelvan Veloo

P.T. Freeport Indonesia currently operate a 600,000 t/d mining and 125,000 t/d milling operation in the remote highlands of Irian Jaya, Indonesia. The isolated location and generally difficult working conditions make for challenges not encountered in most North American operations. In spite of this, the mill technical groups have been able to develop and maintain a highly effective level of plant wide automation. This has been achieved through the appropriate selection of available technologies and the implementation of innovative management practices. This paper provides an overview of the control systems currently installed and focuses on those practices which have resulted in the long term success of process control at Freeport.

Jan 1, 1997

By E. H. Ahrens

This paper deals with the daily work of operating geologists and should be of interest to recent graduates. Working with development and production is quite different from exploration and many of the required skills and techniques must be learned on the job. Try to obtain your first position at a mine where good geological work is being done because it is important that you establish a solid foundation by learning valid techniques. Many do not! Those who desire to work in exploration are well advised to spend the initial two or three years at an operating mine where they will deal daily with an orebody during development and mining. Attempt to understand the controls of ore deposition and be interested in all phases of the operation. Learn something about factors which can adversely affect profitability and you will be a better explorationist.

Jan 1, 1983

By C. R. Nailler

Two recently published papers describing the use of psychological tests for selection and placement of coal mine personnel have created considerable interest within the Coal Industry, one paper, published in the April 1957 "Mining Congress Journal," entitled "Personnel Evaluation and Training," discusses the use of tests by the Christopher Coal Company, The second paper, published in the "West -Virginia Coal Mining Institute's 1957 Report" and in the September 1957 "Coal Age," entitled "Testing to Select Better Personnel for Coal Mining Today," outlines Hanna Coal Company's test and selection procedures. Since these rather detailed sources are readily available, and to avoid repetition of the material in them, we will confine this paper to a very brief review of the essential steps already taken by these companies and a more extensive look at newer material. Briefly, the Personnel Managers, Mr. Harold L, Durrett and Mr. Albert M,. Rowe, of the Hanna Coal Company and Christopher Coal Company, in conjunction with Dr. Quin F, Curtis, Head of the Psychology Department of West Virginia University, developed two different groups oftests for coal mine personnel, The first group oftests was designed to assist in the selection of supervisors. These tests of the supervisory group were "The California Short Form Test of Mental Maturity - Advanced Series," which gave an I.Q. rating, and the second test is known as "The Minnesota Multiphasic Personality Inventory," which measures several personality characteristics, These tests must be given, grade, and interpreted by a person trained in psychological testing. As a result of testing all of Christopher's supervisory employees (seventy in number) by this method, and then comparing the individual results with the individual ratings of the foremen on the job, a so-called foremen's scale was developed. If this resulting foremen's scale had been used to select the foremen who were rated as, the best men in on-the-job performance, it would have correctly identified seventy-four percent of that group.

Jan 1, 1958

By Robert L. Stroup

Let me open my remarks this morning by stating how we as legislators and as natives of the western coal-producing states feel about our role in becoming one of the major producers of coal-related energy and chemical products is similar to the groom at his shotgun wedding. We are apprehensive, to say the least, as to the ultimate outcome. We do not have complete freedom of choice. It will certainly change our quality of life. We are concerned about the increase in population, but are realistic enough to recognize that we are forced to go through with the marriage. Other alternatives could be worse than the bride. Also, we were aware that this could occur, but we did not plan on it being this sudden. Or, put another way, we have two groups advising us that our choices are cattle or coal, food or fuel, pollution and people or pure air, wheat or gas, clean water or prosperity, noise or solitude.

Jan 1, 1976

By S. L. Bessinger

In the design and specification of a ventilation system for an underground mine, it is necessary to make reasonably accurate estimates of the pressure losses in the various airways of the mine. These estimates can be made with little difficulty for open airways with simple geometric cross-sections, such as those cut by continuous miners or tunnel-boring machines. The situation is much different on a longwall face, where the airway's complex geometric cross-section and the presence in the airway of obstructing equipment having a variety of shapes make it difficult, if not impossible, to estimate pressure loss using traditional methods of calculation. Headlosses in mine entries are calculated using Atkinson's Equation (1). [H = (English) H = (SI) (1)] where H = pressure ,loss, in. of H20 (Pa) K = friction factor, lbf min2/ft"4(Kg/m3) P = perimeter, ft. (m) L = airway length, ft (m) Q = airflow quantity, ft3/min (m3/sec) A = flow cross sectional area, ft2 (m2)

Jan 1, 1987

By Donald C. Rotherham

The Endako, British Columbia, deposit was initially discovered in 1927 by two local men, Charles H. Foote and Alf Lagdon, who were at that time on a hunting expedition. Four mineral claims were located to cover an area of quartz-molybdenite float that was centered on two small ridges. They subsequently uncovered a 0.5-m (1.6-ft) wide vein on which an inclined shaft was sunk to a depth of 8.3 m (27.2 ft) in 1934. Additionally, a short adit was driven to intersect another vein. Numerous trenches and small pits were also dug. Small test shipments of vein material from this early work were sent to G.S. Eldridge and Co. in Vancouver for metallurgical testing. A concentrate assaying 89.2% MoS, was produced with a recovery reported as 93.3%. The concentrate was essentially free of copper, arsenic, and phosphate. The property was examined by many geologists and engineers during 1934 to 1952, but the only work done was undertaken by the owners in order to maintain their claims in good standing. In 1952, Kennco Explorations (Canada) Ltd. carried out a limited program of bulldozer trenching, sampling, and geological mapping before relin- quishing their option. In 1956, American Standard Mines Ltd. acquired an option on the property, but no assessment work was apparently recorded and the property was allowed to lapse. The key claims were restaked in 1959 by C. Riley and H.T. James of Vancouver. The property was optioned from the new owners by Andrew Robertson in July 1961, and a small amount of trenching was conducted. Robertson, on behalf of his own company, R & P Metals Corp., reoptioned the property in January 1962. The initial results of this work were favorable and justified further exploration. The additional finances required to continue the program resulted in the formation of Endako Mines Ltd. (N.P.L.) on June 21, 1962. Field work by R & P Metals and the first Endako Mines exploration was directed by Bob Couts.

Jan 1, 1991

By Edward S. Plotkin, Joseph D. Guertin

In a continuing effort to upgrade tunnel design and construction practice, the New York City Transit Authority sponsored a geotechnical monitoring program on a recently completed section of the E. 63rd Street line in mid-town Manhattan. The purpose of the program was to document rock behavior as well as temporary and final rock support systems to provide a possible basis for either confirmation or modificification to design methods and construction specifications. This paper describes those portions of the study associated with rock behavior and temporary support systems. The entire study included monitoring of rock movements above the tunnel as well as adjacent to a 36.6m (120 ft) shaft, monitoring of stresses in steel ribs, monitoring of loads in rock bolts in two test sections and monitoring of stresses in the final concrete lining. PROJECT DESCRIPTION Route 131-A, Section 4 is located in mid-town Manhattan extending from under the Central-Park Zoo on Fifth Avenue eastward under 63rd Street to the end of contract between Madison and Park Avenue. Figure 1 is a Project Locus Map. The contract included approximately 355m (1165 l.f.) of 4 track tunnel(13.4m (44 ft) wide by 13.7m (45 ft) high excavated dimensions) plus a 22.9m (75 ft) by 19.8m (65 ft) by 36.6m (120 ft) deep ventilation shaft. The entire tunnel and most of the excavation shaft was excavated in metamorphic rock, known locally as the Manhattan Schist. The depth to tunnel invert varied from approximately 27.4m (90 ft) at the west end of the contract to 35.Om (115 ft) at the east end. Rock cover above the excavated crown varied from approximately 6.7m (22 ft) at the approximate mid-point of the contract to 18.9m (62 ft) at the western end. A plan view and interpreted geologic profile are illus-

Jan 1, 1979

By P. J. D. Lloyd

INTRODUCTION The mining of gold commenced on the Witwatersrand in 1884, and reached a mature state by about 1910, when nearly 20 million metric tons were mined. Mining has continued on the central Witwatersrand, the area of the first mining, at a similar rate until recent years. As a result, well over 1 billion tons of gold mining wastes have been dumped along a line over 80 km long, centred on Johannesburg and stretching from Randfontein in the west to Nigel in the east. (see Figure 1). The population of this conurbation, which straddles the line of mining, has grown to about 5 million. In 1922 uranium was first discovered as a constituent of the ore (and thus of the wastes). Investigations in the 1940's revealed that values near Johannesburg were low, but that, at the western and eastern ends of the central Witwatersrand line, and in the new areas centred on the towns of Carletonville, Klerksdorp and Welkom up to 200 km from Johannesburg, values were adequate to permit uranium recovery. Commercial production commenced in 1952, and by 1979 over 100 000 tons of uranium oxide had been produced. There thus arises on the central Witwatersrand nearly 1,3 billion tons of slimes containing an average of about 0,005% uranium and about 1,8% FeS2. The material grading is about 70%-75µm, and the primary mineral is silica (over 85%). The material is contained in dams constructed hydraulically. A typical dam has an area of about 100 hectares and there are over 6000 ha under slimes dams in the area of concern. The treatment of these dams for uranium recovery commenced in 1977. The situation has thus arisen whereby potential uranium ores have unwittingly been dumped in significant quantities within a major metropolis over a period of nearly a century. The purpose of this note is to review the experience arising from the potential hazard over a considerable time.

Jan 1, 1980

By Chuck R. McLendon

A new face ventilation system was needed at the Allied Chemical Trona mine, near Green River, Wyoming. The development of an exhaust manifold face ventilation system came from a need to reduce the dust and noise concentration level while maintaining methane control at the continuous miner working face. Dust laden air from a heading being driven by a continuous miner was contaminating the intake air in the mine around the roof bolter operator and adjacent headings. Each working heading was exhausted into the last open crosscut by a face fan. A face fan would contaminate the adjacent downstream heading with dust-laden air until a high dust concentration developed in the final entry before the returns. A face ventilation system was needed to give the exhaust of each heading an individual path to the return air. In addition, the system could not interfere with the present room and pillar mining process. A manifold system of rigid duct ventilation tubing was designed using the existing fans in a parallel arrangement. Each system was to consist of the rigid duct tubing in three headings junctioned together at the last open crosscut and exhausted at a common branch in the return air. Each heading was to have its own damper (or valve) so that air could be directed where it was most needed. The system was installed using both round and oval rigid duct ventilation tubing to minimize head loss and to allow proper ground clearance for mining machinery. Two fans in parallel were used to exhaust three headings. By adjusting the valves at each heading, up to 18.0 kcfm (9.36 cu m per sec) could be exhausted from one heading and still keep the methane level controlled in the other two headings. The manifold exhaust system has proven to be an efficient, long lasting ventilation system at the Alchem Mine. It has reduced the dust and noise exposure levels at the working faces while keeping the methane level under control.

Jan 1, 1980

By Finn E. Bronner

HISTORICAL PERSPECTIVE "Blessed be the Lord my strength, which teacheth my hands to war and my fingers to fight." Thus sang David three thousand years ago, in tacit acceptance of the condition of war, and in praise of the exceptional military skills with which this warrior king of Israel was endowed. He had cause to exult, for he had consolidated King Saul's conquests and added new ones of his own, not least of which was the capture of Jerusalem. David revealed in this operation that his mastery of the military arts embraced not only the weaponry and tactics of his day, but also strategy and that oldest of intelligence techniques: spies. The Jebusites, who built Jerusalem, had encompassed the city with the first of its many walls, but had neglected to incorporate the sole reliable water supply within its perimeter. This was Ain Gihon, today called the Fountain of the Virgin, which bubbled out on the east slope of Mount Ophel, one of the ridges on which Jerusalem was built, and drained eastward into the Kidron Valley. Water was brought into the city in the traditional manner: by women descending the stony trail outside the wall to fill their jars at the spring. But this essential daily activity was vulnerable to interruption by a hostile force outside the walls. To remedy this weakness, the Jebusites had driven a gallery from the spring a short distance into the water-bearing limestone under the city, and there cut a small collecting basin in the rock, a common way to develop springs throughout this arid region. But then the Jebusites dug a small vertical shaft from the roof of the gallery above the cistern upward about 15 m. From the upper end of this shaft, they constructed a narrow inclined tunnel with rock-cut steps leading up to the city streets. Thus the water supply could be reached even in time of siege.

Jan 1, 1979

By Barnaby J. Watten, Sibrell. Philip L., Brian J. Vinci, Andrew E. Friedrich

We evaluated a new process for remediation of acid rock drainage (ARD). The process treats ARD with intermittently fluidized beds of granular limestone maintained within a continuous flow reactor pressurized with CO2. Tests were performed over a thirty day period at the Toby Creek mine drainage treatment plant, Elk County, Pennsylvania in cooperation with the Pennsylvania Department of Environmental Protection. Equipment performance was established at operating pressures of 0,34,82, and 117 kPa using an ARD flow of 227 L/min. The ARD had the following characteristics: pH, 3.1; temperature, 10 OC; dissolved oxygen, 6.4 mg/L; acidity, 260 mg/5; total iron, 21 mg/L; aluminum, 22 mg/L; manganese, 7.5 mg/L; and conductivity, 1400 uS/cm. In all cases tested, processed ARD was net alkaline with mean pH and alkalinities of 6.7 and 59 mg/L at a CO2 pressure of 0 kPa, 6.6 and 158 mg/L at 34 kPa, 7.4 and 240 mg/L at 82 kPa, and 7.4 and 290 mg/L at 117 kPa Processed ARD alkalinities were correlated to the settled bed depth (p<0.001) and CO2 pressure (p<0.001). Iron, aluminum, and manganese removal efficiencies of 96%, 99%, and 5%, respectively, were achieved with filtration following treatment. No indications of metal hydroxide precipitation or armoring of the limestone were observed. The surplus alkalinity established at 82 kPa was successful in treating an equivalent of 1136 L/min (fivefold dilution) of the combined three ARD streams entering the Toby Creek Plant. This side-stream capability provides savings in treatment unit scale as well as flexibility in treatment effect. The capability of the system to handle higher influent acidity was tested by elevating the acidity to 5000 mg/L with sulfuric acid. Net alkaline effluent was produced, indicating applicability of the process to highly acidic ARD.

Jan 1, 2000

By Marcel Laflamme, Sebastián Ibarra‑Gutiérrez

Improvement on controlling the stope limits has enabled the assessment of technical performance in several underground mining operations. Technical performance, integrated to stope geotechnical and geomorphological parameters, constitutes the basis which guides mining engineers in the Mineral Reserves Estimation process. Moreover, there are established definitions to report this information in Canada, incorporated in NI 43–101, which stipulates that “A Mineral Reserve includes diluting materials and allowances for losses that may occur when the material is mined” [1]. However, some loopholes have been identified regarding practical standards followed to specify the way to include and report ore losses when the lost material was blasted and must be left behind unrecovered inside the stope. In fact, general efforts to estimate and quantify the negative effects of operational ore losses only consider under-break ore loss. However, mining engineers frequently confront situations requesting the anticipated closure of a stope. Therefore, reconciliation process should reflect the amount of unrecovered Mineral Reserve. This work presents a discussion of possible practices to integrate adequately operational ore losses consisting of blasted but not recovered material and focuses on how different approaches regarding the material constitution could severely affect the stope technical performance interpretation.

Aug 9, 2021

By Frank P. Traczyk

INTRODUCTION The process of solid-liquid separation can be an important decision in plant design. It is very important that one must consider not only the most effective means of solids-liquid separation, but also to consider the effects on upstream and downstream processes. A solid-liquid separation is done either to remove the solids £ran the liquids as in copper concentrates or rave a liquid from the solids as in uranium operations. In either case, washing can be an important consideration to clean the solids or recover the liquids. This section will deal with solid- liquid separation other than thermal, sedimntation processes, or hydro cyclones. The three major areas discussed are pressure filters, vacuum filters, and centrifuges that are most cannon in the minerals industry. PRESSURE FILTERS Pressure filters are one common type of solid-liquid dewatering devices. There are my different types of pressure filters that are both continuous and batch operations. They are characterized by using an external pressure to push or force the slurry through porous media to force the liquids out of the solids. Whereas vacuum filters are limited to one amsphere or bar working pressure, some types of pressure filters operate as high as 16 bars pressure. Pressure filters are also effective for hot slurries where a high boiling point can be a problem or precipitation occurs under vacuum. The types of pressure filters most common in the mineral processing industry include plate and frame and recessed plate filters. Some of the new technologies including automatic pres- sure filters and belt presses are also discussed. Plate Frame Filters Plate and frame filters are one of the oldest and most effective means of both dewatering solids and clarifying liquids. Plate and frame filters consist of a skeleton that is used to hang or support alternate plates and frames that are pressed together to form chambers. The filter plates consist of a drainage grid that is covered by sane type of filter media through which a liquid is

Jan 1, 1986

By T. P. Meloy

The packed column flotation cell is an awesome separation device. Virtually unknown and untested, the packed column flotation cell is one of the ten most important developments in mineral processing of the 21st century. Though experimental and industrial data is limited, it is clear that the packed column flotation cell is two to three orders of magnitude better than the conventional flotation cell and one to one and a half orders of magnitude better than the open column flotation cell. With the modern packing taking up less than one percent of the packed column, column blocking does not occur. For a packed column operating 24 hours a day, 365 days a year, the estimated mean time between failures (MTBF) is one hundred thousand hours or roughly twelve years. With no moving parts, lower maintenance costs, lower power consumption and inherent operating stability, the packed column is a powerful separating machine. Because there is little meaningful data for comparing the packed column to the conventional flotation cell and the open column flotation cell, much of the material presented in this paper are guesstimates. They are disinterested guesstimate made by the authors after extensive theoretical work and reviewing the known facts. In the authors&apos; opinion, no available data contradicts the guesstimate. The authors expect that there may be errors as large as three hundred percent. Even three hundred percent errors will not change the conclusions of this paper. The packed column flotation cell is a formidable separating device. To understand the problems of comparing the three types of flotation cells, consider the fact that the three cells may have different modes of separation. One of the authors, Meloy, believes that in the conventional cell, the primary particle separation takes place in the liquor with secondary separation taking place in the froth, while for open column flotation, all the separation takes place in the froth. However, he believes that in the packed column a large part of the separation may take place on the walls of the packing. If this is true, not only is the method of modeling each type of cell different, but the method of particle selection in the cell is different. This means that one type of cell may be better at differentiating between two different types of particles. There is a growing body of literature on open and packed column flotation. Suggested reading: (Clarke et al; Hucko et al; Li; Smith & Warren; and Yang).

Jan 1, 1994

By L. George Imperato

The Blocked Iron Corporation has been active for many years in the development of mineral agglomeration processes by cold chemical induration. Millions of tons of iron ore fines agglomerated by their methods have been consumed in open hearth steel making furnaces. Some of you may remember these open hearth agglomerates as the carbonate-bonded cylindrical block shown in figure 1. With the realization that iron making would create the greatest demand for agglomerates our research efforts were directed to the production of carbonate- bonded (C-B) pellets containing iron ore, flux and carbon, shown in figure 2.

Jan 1, 1968

By V. D. Hanson

When maintenance of a plant or operation is under discussion immediately three "M&apos;s", all in short supply, are brought to mind - money, men and markets. This paper will present what currently is being done at our plants and its effect on the 3 "M&apos;s". Examination of coal realization figures (F.O.B. Mine) from 1945 to the present reveals the fact that open and free competition can and will meet market conditions. The industry, without benefit of advantages afforded tax and transportation wise to oil and gas, remains the backbone of the energy market of United States. Figure No. 1 shows the realization figures from 1945 through 1962 compared to the hourly earnings. Note that through 1945 to 1948 F.O.B. prices increased $1.93 per ton while hourly earnings increased $.66 per hour. Since 1948 (with the ex¬ception of 1957) F.O.B. prices have declined $.45/ton, while hourly earnings have increased $1.23 per hour. Basically the maintenance men possibly represent the highest increment rate in the overall hourly earning.

Jan 1, 1963