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By S. A. McGhee

ASARCO Incorporated embarked on a modernization and expansion program to improve overall operating efficiencies and to more effectively develop the large mineral reserve at the Ray Complex Open-Pit Mining operation located near Kearny, Arizona. Major elements of this Ray Modernization and Concentrator Expansion Project included engineering and construction of a 54,400 MTPD (60,000 STPD) In-Pit Crusher and Overland Conveying System. and a 24,200 MTPD (30,000 STPD) Copper SAG Concentrator and Tailings Disposal System. Detailed engineering, procurement, and construction management were initiated in November 1989 under contract with Bechtel Corporation. Field construction commenced in May 1990 leading to mechanical completion and start-up during February 1992.

Jan 1, 1993

By R. Tamir

This paper will describe the benefits of utilizing the decision support system, DSS to support the methodology of structured decision-making in the mining environment. It will outline the layers of the mining related decision making – 1. Creation of “one truth” situational awareness utilizing 2. existing planning, ERP, operational and monitoring agents, a. Expressing plan verse performance across mining phases and functions compared with the actual and trends to evaluate performance. b. Creating alternate courses of action and the implications up and downstream. 3. It will review the current condition were although a multitude of technologies resolve multi variable issues they do not interact in a way that assists decision makers throughout the organization in making high-quality decisions that will push the overall performance envelope. 4. The paper will show the benefits of integrating military methodologies to resolve multi variable complexed issues (operational, financial and other), operating in changing environments in order to meet time sensitive objectives with restricted resources. This is achieved by creating a shared situational awareness thru incorporating information from a multitude of data generating agents, creating COA, selecting the appropriate and turning it into a plan. The paper will discuss the implementation and suggest a path.

Feb 1, 2023

By S. G. Britton

Microcomputer analysis has long been a technique for engineering professionals to improve the theoretical and practical design of continuous mining systems. Such work has been typically composed of modeling observed events and then introducing a variety of known elements with predicted results to compare against the results of the model. Programs written in BASIC, Cobol, Fortran, or other language dominated such efforts. These programs have taken years to develop and prove out. This paper explores a new management tool used at TMC on a daily basis to track and improve continuous mining systems through the use of microcomputers and Lotus 1-2-3 software. By analyzing data provided by section foreman, shift foreman, and maintenance personnel against predetermined goals, new production targets are developed, weaknesses in the current mining systems are identified, and the results of changes are measured. The results of this system on the productive output of TMC systems are on the order of ten percent improvement.

Jan 1, 1991

By B. A. Massey

Sooner or later, we'll encounter a subordinate, peer, or boss that will test our management skills to the limit. The chances are good that our formal educations have not fully prepared us to effectively handle the situation, and through trial-by-fire, we have learned that the management of people is often as much an art as it is a science. Assertiveness - as opposed to agressiveness - is basically positive persuation. Assertive management techniques can help combine the art and science of managment to sell ideas, accomplish goals, direct the workforce, and generally promote the corporate - as well as our own - objectives

Jan 1, 1986

By Pedro D. Lasota

Chile leads the world in copper production with an annual capacity nearing 2 Mt (2.2 million st). Most of the country’s copper production, about 74%, is mined by open-pit mining methods. Open-pit mining also accounts for a major portion of Chile’s production of other commodities, including iron, gold, silver and coal (Table 1). Chile’s mining boom began 10 years ago and is expected to continue through the end of the decade. From 1980 to 1990, copper production in Chile increased 48.7%. During the same period, gold production increased 303%, silver production increased 119% and coal and iron ore production increased 163.7% and 6.6%, respectively (Table 2). It is estimated that copper production will be in the order of 2.3 Mt (2.5 million st) by 1996, when new projects now under construction come onstream. Gold production could reach 35 t (1.1 million oz) and coal production could increase another 1 Mt/a (1.1 million stpy). Open-pit mining has played a significant role in Chile’s minerals production growth. The expected increases in mine operations will come about mainly through new open pits or expansions of existing surface operations (Table 3). However, the number of open-pit copper mines will decrease from 74% to 66% of the total number of Chilean mines. Gold mines will increase from 63% to 69% of the total, while coal mines will go from 41% to 59%. Most all of the present iron ore production is from surface mines and will continue that way.

Jan 1, 1992

By J. R. Heberger

"The Safety Pays in Mining web application, developed by the National Institute for Occupational Safety and Health (NIOSH) Mining Program, helps mines determine the potential costs associated with mining injuries. This web app groups injuries by type, either by the cause of the injury or by the nature of the injury. When the user selects one of over 30 common types of mining injuries, the app provides information on the distribution of costs of workers’ compensation claims for that type of injury. Based on other user inputs, Safety Pays in Mining will estimate the total costs of the selected injuries, including an estimate of additional indirect costs, the estimated impact of total injury costs on mining company profits, and provide some examples of other items (services, equipment) on which companies could spend the savings that result from the prevention of injuries. This paper reviews the Safety Pays in Mining web application by discussing the development of the app, how it is used to show the true costs of mining injuries, and how mines can benefit from using this app. INTRODUCTION Injuries on the job cause pain and suffering. They can also profoundly affect profits and daily operations. In addition to paying direct costs or increased premiums for workers’ compensation insurance, a company might need to pay overtime for other workers to fill an injured worker’s job role, cover training costs for a replacement worker, or divert administrative resources in the wake of an injury. Safety Pays in Mining is a web app that estimates the distribution of these injury costs and assesses the impact that occupational injuries have on a company’s profits. The costs of specific types of occupational injuries in mining are not readily available as mining and insurance companies don’t usually share this information. As a consequence, companies only have cost information based on previous experience with their own employees. Therefore, if a mine never experienced a finger amputation for one of its miners, it would not be aware of the possible costs associated with this type of injury. In addition, injury costs are unique in that the cost distribution is so wide — with half of the injuries in our dataset having mean costs higher than 90th percentile costs — just using the average cost of a specific injury type does not provide adequate information. Some injuries involve immensely high costs, and even though the risk of these high-cost injuries occurring is low, mines need to be aware of their potential impact on their company’s financial health."

Jan 1, 2018

By Johannes Jäger

"A composite shell lining typically consists of an outer permanent sprayed concrete shell, a water proofing layer and an inner sprayed or cast concrete shell. Composite shell linings become more and more popular and have been built recently on large scale infrastructure projects. Surprisingly there is very little published literature on the actual structural design of composite linings. As a consequence there is a lack of common understanding on how to design a composite lining structure. Composite action of the outer shell (primary lining) initially carrying short term ground loads and the “unloaded” inner shell (secondary lining) require nonlinear concrete modelling to be able to assess the bearing capacity of the composite lining structure adequately. The composite action of the waterproofing membrane and the inner and outer shells can be considered either by simplified closed form solutions or by numerical models. Strength and stiffness parameters of membrane and concrete govern interaction of inner and outer shell. This paper should contribute to understanding composite lining behaviour with focus on the bearing capacity at limit state by taking into account the actual loading history. Possible ways and concepts on how to deal with these topics are presented, however a broader discussion on limit states of the composite lining materials – also in the long term will be required to come to an agreement on composite lining design methodology. INTRODUCTION Composite Lining Technology Traditionally the construction of shotcrete lined tunnels incorporates primary and secondary linings, separated by a sheet or a sprayable waterproofing membrane. The primary lining shotcrete is considered to be structurally temporary and the secondary lining to be permanent, leading to designs which ignore the bearing capacity of the primary lining in permanent condition. There was general perception that the shotcrete lining installed immediately at the tunnel face, experiencing strains up to 1% and even cracking in the early age, combined with mesh reinforcement additional support measures like lattice girder, spiles and bolts cannot be considered as a permanent structure. But also former shotcrete mixes showed significant weakness with respect to durability suggesting a more temporary nature of primary lining shotcrete. On the other hand it was clear that primary lining shotcrete does not disappear, it may lose probably a certain percentage of its bearing capacity, but discounting any contribution from the primary lining at all was considered inherently conservative. There were different strategies to account for the risk of reduced durability and bearing capacity of the primary lining, either by selecting moderate ground loads for the secondary lining design, by assuming that some residual load will be carried by the primary lining. This approach is very much based on experience. Another more rational possibility is to assume that the primary lining degrades into a rocklike material, which is weaker than the primary lining shotcrete but still imparts some strength to the ground around the secondary lining, but does not need to comply with any concrete design codes any more."

Jan 1, 2016

By Adam Bedell, Paul Derby, Brad Crenshaw

Modified contact grouting was introduced almost 15 years ago as a methodology combining traditional contact grouting and consolidation grouting to address groundwater infiltration into hard rock tunnels that utilize cast-in-place concrete as permanent tunnel support. This process has been used on additional tunnels (since initially presented) as a measure to mitigate both groundwater infiltration and exfiltration. During this time, self-sealing grouts have been developed and have been added to the process to further reduce groundwater infiltration that occurs through cracks and discontinuities within the concrete liner itself. This modification is presented and additional results from the grouting process are discussed.

Jun 13, 2021

By Paul C. Lingo

Two recent antitrust cases, coming from widely separated areas, different industries and involving wholly different facts were decided by the Supreme Court on June 7, 1965. The decisions in these two cases may well prove to be the most important and far-reaching decisions in the field of labor law that have been handed down in the last 24 years. These cases, although quite dissimilar factually, had one common element. In both, the gravamen of the antitrust violation was bottomed on the terms of labor agreements negotiated by a multiemployer group. These cases are usually referred to as Pennington1 and Jewel Teat. Since a number.-of references will be made to the antitrust laws, it may be well to state briefly the applicable portions. Section I of the Sherman Antitrust Act makes "every contract, combination in the form of trust or otherwise, or conspiracy, in restraint of trade or commerce among the several states, or with foreign nations, is declared to be illegal...". Section 2 imposes criminal sanctions against "Every person who shall monopolize, or attempt to monopolize, or combine or conspire with any other person or persons, to monopolize any part of the trade or commerce among the several states...". Under Section 4 of the Clayton Act a person who sustains damages as a result of a violation of the antitrust laws is entitled to recover treble damages plus costs.

Jan 1, 1965

By Jürgen Kretschmann

Principally, mining natural resources is a finite business that reaches its limits once the deposits mined are depleted, the resources can no longer be mined in an economically profitable way or substitutes are pushing the mined products out of the market. An example of the latter is the increasing replacement of coal with natural gas and renewables in power generation in the United States [1]. According to the model of the product lifecycle, the global hard-coal mining industry has reached a stagnation phase [2]. The trend is obvious. Coal use peaked in 2013 [3], and the coal demand of China has been slowly decreasing since then [4]. Coal consumption in the United States saw a 16 percent decline from 726 Mt (800 million st) to 608 Mt (670 million st) between 2015 and 2019. In addition, according to the U.S. Energy Information Administration, it will not rise again [5]. The decline is attributed to complex market dynamics, from low gas prices because of the “shale gas revolution” [6] to federal environmental regulations like the Clean Power Plan. Moreover, important players like the United Nations and the European Union have already begun to describe pathways toward decarbonization. Increasing competition between coal-mining companies and the mining regions can be expected worldwide if companies want to keep their positions on the global and national coal markets. Companies will focus on the best deposits. European countries, like France, Spain or Germany, are only forerunners of this development — their centuries of coal production have passed. The concept of sustainable development (SD) is fundamentally based on a model of progress in which ecological, economic and social dimensions should be developed equally and positively. Questions arise, such as: How can SD be a corporate goal in a phase of decline? How can former mining regions sustainably progress to a better future? The steps Germany has taken to handle the coal decline in a sustainable way and the lessons learned from this process are described in this paper. 

By Barry J. Hansen

In the past six years, the Hanna Mining Company has increased its pellet producing capabilities greatly by the construction and expansion of six pelletizing plants in North America. At the present time Hanna managed pelletizers have a nominal capacity of 18 million long tons per year. This capability makes Hanna one of the world's largest pellet producers. To create and maintain such an operation has required the skill and dedication of many people in all aspects of the company's activities, in the various fields of exploration, operations and research. The Research and Development Group consists of the staffs of two laboratories situated on the Mesabi Range in northern Minnesota. These laboratories are well equipped to carry out work in the fields of beneficiation and extractive metallurgy especially iron ore treatment. Facilities exist for the batch and semi- continuous investigation of the unit operations common to iron ore beneficiation and pelletizing. The R and D Division is divided into groups according to specialized areas of interest. Presented in this paper today are some aspects of the activities of the Pelletizing Group of the Research & Development Organization.

Jan 1, 1969

By A. Taghavi, I. Hassan, A. Solecki

"The Eglinton Crosstown Light Rail (LRT) Project is part of an $8.4 billion investment to expand transit in the Toronto, Canada area and is the largest transit project initiated in Province’s history. Settlement control and impact to over 1400 adjacent structures due to tunnelling was identified early as a critical project risk. The ground conditions along the 10km tunnel alignment consist of water bearing soft ground deposits (clays, sands, silts) which required careful analysis and control during design and construction. This paper will describe the process used to analyze settlements along the numerous of adjacent structures and evaluate achieved settlement results to those used during design. The paper will demonstrate that with the appropriate design specifications, selection of modernized EPB machines, and contractor performance, settlement can be maintained well below typical industry (volume loss) standards, expanding the application and suitability of soft ground tunnelling in sensitive settlement areas. INTRODUCTION The Eglinton Crosstown Light Rail Transit (LRT) Project is part of an $8.4 billion (2010$ CND) investment from the Ontario provincial government to expand transit in the Toronto, Canada area. The project is being developed by Metrolinx, an agency of the Government of Ontario to provide 19 kilometers of dedicated LRT service connecting the City of Toronto from the west to east along Eglinton Avenue. Upon completion in the year 2020, the Crosstown will be the first LRT constructed in Toronto. It will link regional and local transit, cut travel time along the route by half and provide over a thousand jobs during construction."

Jan 1, 2016

By G. S. Dobby

The Cu-Au flotation cleaning circuit at Freeport Indonesia consists of three stages: two flotation column stages, in series, followed by one stage of mechanical cells. Concentrate from both column stages is combined as final concentrate. The mechanical cell stage has two parallel rows of seven Wemco 500's. The Wemco concentrate is recycled to feed of the second column stage and Wemco tails report to final tailings. This paper examines cleaner circuit performance, focusing on size-by-size performance of the individual stages and the individual mineral groups -copper sulfides, gold and in sol minerals. The recovery mechanisms of insol minerals are examined.

Jan 1, 1995

By J. Patrick Powers

In tunneling through water-bearing formations, the expense of controlling the water can have a major impact on overall project cost. The author has seen the cost of an eight-foot, finished sewer tunnel rise from under $500 per foot to over $1,000 when a water problem, anticipated as modest, became severe. There is need for greater professionalism in the approach to groundwater control. The days of the forked stick should be behind us. The basic technology exists. Its application is not yet widespread. This paper discusses predrainage; that is, the lowering of water in advance of tunnel excavation. Both free air and compressed air tunnels are considered. Examples from recent tunnel projects are described. SPECIAL NATURE OF TUNNEL DEWATERING Tunneling is unlike other excavations below the water table in a number of significant ways. The tunnel excavation is always on the critical path; if production slows or stops, there is no other work for the heading crews, no other work to carry the cost of service crews and job overhead. The dewatering commitment must be made well in advance. Construction of wells, and pumping down take time. After the heading reaches a trouble area, time is not available

Jan 1, 1997

By J. `. Spitzinger

In situ recovery (ISR) of uranium alters the baseline groundwater geochemistry in order to mobilize and complex uranium to extract and concentrate it. ISR wellfield restoration is often challenging, and primarily relies on groundwater sweep, reinjection of treated permeate, and/or injection of reductants. Greater focus should be placed on injection-based approaches (using existing infrastructure) based on established engineering concepts used for in situ remediation of groundwater plumes. Such injection-based approaches could shorten restoration timeframes consequently reducing long-term operational costs. This paper addresses various types of injection-based approaches to wellfield restoration based on in-situ remediation success with other constituents that require similar treatment. This paper describes necessary design practices for injecting reactive chemicals (e.g., reductants or biostimulants), operations and maintenance (O&M) strategies to prevent fouling of the chemical delivery system and well network, and natural constraints to restoration. Best practices for successful biostimulation strategies that minimize residual uranium, radium, oxoanions, and other trace elements are as described. Advantages of such injection-based approaches could include significant reductions in restoration times, and consequently, lower restoration costs.

Feb 23, 2014

By J. G. Groppo

Froth flotation has been shown to be an effective method for reducing Loss-on-Ignition (LOI) of ponded or landfilled fly ash. Reduction of LOI is required for many fly ashes, particularly those produced from low-No, burners, in order to meet ASTM requirements for use as a mineral admixture in Portland cement concrete. An additional ASTM requirement, fineness, is critical in determining end use applicability, and in many cases, classification of fly ash is necessary to produce an acceptable product. Hydraulic classification has been shown to be a simple, cost-effective method for classification of a variety of minerals including silica, phosphate, mica, coal, etc. and has shown to be similarly effective on fly ash. The combination of froth flotation and hydraulic classification facilitate the production of a high quality pozzolan that meets or exceeds ASTM specifications. This combination has been rigorously evaluated and results of pilot-scale testing are presented. Pilot scale testing was conducted on fly ash from two active utility storage ponds and demonstrated that high quality, consistent pozzolan could be produced using APT's Fast Float? Technology. Along with the pozzolan, additional production of aggregate for masonry mortar and a low sulfur, medium Btu fuel were also demonstrated. The Fast Float? process incorporates several simple unit processes to ensure pozzolan consistency; classification controls particle size distribution which is critical to achieving early strength, flotation controls the grade with respect to L.O.I. (Loss on Ignition) while dewatering controls the moisture content.

Jan 1, 1998

By R. E. Ray

As coal reserves at shallow depths continue to be exhausted, a number of U.S. coal mining companies are beginning to develop coal seams previously thought to be coo deep to mine economically. Because of increased cover load, mines operating in deeper seams face unique ground control problems. In addition, the volume of methane gas contained in coal beds increases with depth, and ventilation requirements are much more stringent for deep underground coal mines than for shallower mines. When the longwall mining method is used at great depths, ventilation, ground control, and operational considerations must all be addressed in the design of longwall panels. This paper examines the influence of these factors, particularly ventilation and operational considerations, upon the feasibility of two, three, and four-entry longwall development panels in Jim Walter Resources' four deep mines.

Jan 1, 1986

By William Gleason

For the first time in many years, the Liebherr Group chose to host its annual conference for the international construction trade press in the United States. The reason for the move is simple ? mining. Like other large corporations, especially those in the construction fields, Liebherr felt the effects of the global economic crisis that began in 2008. The slowdown in the housing market was especially hard on Liebherr?s mobile crane and earth moving divisions. The mining division, however, while affected by crashing commodity prices that led to cancelled orders and the loss of financing for some customers, was not battered as badly as the other divisions. And now, with the price of commodities once again on the rise, it seems that it will be Liebherr?s largest machines that lead the family-owned company to better days. ?We can report that our generally optimistic view during the crisis has proved adequate,? said Joachim Janka, president of Liebherr mining equipment, at the conference in Williamsburg, VA, just down the road from the company?s mining truck division global headquarters in Newport News, VA. ?Since the third quarter of 2009, our mining equipment activities have been recording once more a strong and steady demand. This has already yielded a substantial increase in market shares for our product lines of large mining shovels as well as for mining trucks.?

Jan 1, 2011

The National Mining Association’s (NMA)MINExpo International ’96 is shaping up to be the organization’s largest. About 30,000 mining industry business and technical professionals are expected to descend on Las Vegas, NV Sept. 9-12 to take part in the 25 technical sessions and visit the more than 900 exhibitors who will be showing off their products and services. MINExpo will be the largest mining equipment and services exposition in the United States this year. Exhibits at MINExpo will fill the Las Vegas Convention Center, parking lots and part of the Hilton Center, located next door to the convention center. NMA estimates that this year’s show will cover more than 46,450m2 (500,000 sq ft) of exhibit space. Some of the exhibits on display will include haultrucks, hydraulic shovels and excavators, conveyors, continuous miners and tunneling machines. In addition, an array of computer equipment and software will be demonstrated. A new feature this year will be a helicopter pavilion, located in the Hilton Center. Helicopters and fixed-wing aircraft have become indispensable to many remote mining operations. NMA said that at least one full-size helicopter will be on display.

Jan 1, 1996

By N. B. Aughenbaugh

Subsidence due to abandoned coal mines has received copious attention recently. This is a result of many factors such as the enactment of new mining laws and the effect subsidence has on land use over the mines. Prediction of subsidence features and the time aspects over supercritical extraction (i.e., longwall and high extraction ratio pillaring) is relatively accurate. However, predicting when subsidence will occur and the surface features' size and shape above subcritical extraction of room and pillar mining is not yet possible. This paper will discuss the factors that influence the time aspects of subsidence in room and pillar mining.

Jan 1, 1983