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By D. J. Wood

BHP Copper has grown, in just over six years, from a minor participant to the world's largest privately owned copper producer. BHP Copper's major asset is the world's largest copper mine -Escondida in Northern Chile. Ten years ago investing in Chile was considered high risk. Today, Escondida represents an investment of approximately US$2 billion. Reward is the result of managed risk and Escondida is a clear demonstration of both. The Ok Tedi copper and gold mine in Papua New Guinea represents a Rubicon of risk and a retrospective on reward in a developing country on the doorstep of a developed one. The story of these two mines encapsulates risk in the mining industry.

Jan 1, 1998

By Charles M. Brinckerhoff

Everyone -- especially the engineer -- is aware of the great technological and social changes taking place in our world today, We realize that changes have been taking place since man's beginnings on earth, but the element we now face is the speed of change, rather than change itself. Developments in medicine, in transportation, in space exploration, in global communications, and in many other fields, are constantly being made known. These developments are affecting the lives of each of us, although some may appear remote and unrelated to us as individuals. New developments, almost on a daily basis, affect our work as well as our social, religious and educational lives. The effects are immediate and permanent.

Jan 1, 1967

By J. P. De Carvalho, R. Dimitrakopoulos

An actor-critic reinforcement learning approach is presented to improve the production of an industrial mining complex by defining shovel allocation and adapting the short-term plan given grade-control decisions. Blasthole data updates the simulated orebody models, which are input into a stochastic grade-control method based on a spatially constrained clustering approach that minimizes the profit-loss function. These aspects are embedded in a discrete-event simulator that defines the material flow from faces to processors. A case study at a copper mining complex shows the methods’ ability to adapt to new information, improving the quality of the material feed and increasing cash flow by 23% compared to a baseline case.

Jun 25, 2023

By R. G. Darmody

Longwall coal mining in southern Illinois occurs beneath some of the best agricultural land in the U.S. This region is characterized by highly productive, nearly level, and somewhat poorly drained soils. Subsidence from longwall mining causes changes in surface topography which alters surface and subsurface hydrology. These changes can adversely affect agricultural land by creating wet or ponded areas that can be deleterious to crop production. While most subsided areas show little impact from subsidence, some areas experience total crop failure. Coal companies are required by law to mitigate subsidence damage to cropland. The objective of this study was to test the effectiveness of mitigation in restoring grain yields to their pre-mined levels. The research was conducted on sites selected to represent conventional mitigation techniques on the predominate soils in the area. Corn (Zea mays L.) and soybean [Glycine max.(L.) Merr] yields in 1988, 1989, 1990, and 1991 from mitigated areas were compared to yields from nearby undisturbed areas. There was no significant (a=0.05) difference in soybean yields averaged over the four years. Average corn yields, however, were significantly lower than reference areas. The impact of subsidence and mitigation is variable and site specific. Results were also related to weather. In wet years, yields in mitigated areas tended to be depressed. This research demonstrated that mitigation of subsidence damage can be successful.

Jan 1, 1986

By D. Puckett

The feasibility of maintaining equipment location, personnel location and vital statistics in surface and underground mining operations has increased with advances in radio frequency identification (RFID) technology. The paper addresses the use of this technology, relatively new in the mining industry, to track surface equipment in mine pits, loading points, and processing facilities. Specific applications are discussed including a simplified and a complex truck tracking system and an automatic pit ticket system. The paper concludes with a discussion of the future possibilities of RFID technology in mining, such as monitoring biofeedback of personnel (heart and respiration rate, body temperature, exertion level, etc.) repetitious movements to study work habits, and logging air quality via personnel sensors.

Jan 1, 1996

By Frederick J. Hoppe

The productivity or usefulness of a Front End Loader rises rapidly with its size. Loading is more aggressive. Mother Nature is defeated more easily. Larger tires get a better grip on the ground. Hauling equipment can be loaded more quickly. The productivity or usefulness of a Front End Loader is proportional to its working speed, both automotive and hydraulic. The price of speed is horsepower, which rises rapidly with speed. Horsepower saved shows up as increased productivity. This paper covers the development of the D600, KW-Dart's articulated loader, which combines massive size with new concepts to increase its working speed. Featured is a discussion of the horsepower saving, "Balanced Boom."

Jan 1, 1969

By Heinz C. Dittmar

The phenomenon of radioactivity has been known since the turn of the last century. Scientists of many nations, intrigued by the strange effects of radioactivity, have engaged in research to probe the heretofore presumed, but largely unknown world of atomic structures and subatomic- particles. A theory evolved of splitting the atom, thus providing insight into the structure of matter and opening the way to possibly create new materials. Many years of effort culminated in the first chain reaction in 1942. The beginning of the atomic age was drastically demonstrated by the flash of the large scale chain reaction of the first atom bomb. It was actual proof of the incredible energies contained in matter.

Jan 1, 1966

By P. Mendoza, R. Siwale, H. Amini, R. Silva, M. Richards, V. Ngcoza, D. Rivera, C. Canaza, R. van Reenen

Development of a realistic flotation model to predict its performance is of paramount importance to the processing plant and operators, a model that accounts for predictive and no-predictive maintenance simulating individual equipment downtime and the effect of it in the metallurgical performance on the flotation bank with final recoveries and grades has a huge advantage on optimizing the flotation circuit/bank in terms of mechanical and metallurgical side. The Model was developed in a dynamic environment that allows for a better and more realistic simulation of the flotation bank. The maintenance model accounts for the Failure rate, Mean Time Between Failures (MTBF), Mean Time to Failure (MTTF) and Reliability (R(t)) those characteristics are combined to a multi-compartment process model that consists of a slurry recovery model, two options of froth recovery models, entrainment and carry capacity as a final check for the system. In addition to the maintenance and process model, a dynamic dart valve model was added to the simulation in order to have a realistic model to control the slurry level at the flotation cell. The paper goes over a study case for a current flotation operation trying to explore all the elements and the simulator to optimize the Rougher flotation bank.

Mar 2, 2022

By Robert Bissonette, Samir Sbai

Machine Situational Awareness (MSA) requires the ability to efficiently evaluate the probability of interaction of objects within the environment, without creating false alarms or ignoring materializing hazards. To do this, an MSA system needs to assign context to observed object activity and integrate as much information about object identity, kinematics, behavior, and current state as possible. This paper describes how known object characteristics, attributes, and activities (drilling, dumping, driving, etc.) can refine interaction probabilities and help identify rogue actors that introduce anomalous risks to the health and safety of miners. Path projections need to incorporate velocity and direction as a function of time while accounting for terrain, safety response, environmental factors, current assigned activity, etc. This paper also describes the methodology for properly prioritizing responses to place the highest value on human safety.

Feb 1, 2024

By Nick Katsikaros, A H. Gray

Gold concentrates are produced at many mines by a variety of centrifugal and gravity machines, such as Knelson and Falcon concentrators, however the subsequent recovery of gold is relatively inefficient and subject to security problems. The InLine Leach Reactor (ILR) offers a new method to recover over 95% of gold in concentrates using a simple, secure leaching process. The InLine Leach Reactor is of particular benefit in treating slow or difficult leaching sulphide concentrates and its performance can be reliably predicted from simple laboratory tests. The InLine Leach Reactor is now successfully operating in two gold mines providing benefits of high gold recovery, low operating costs, high security and ease of operation.

Jan 1, 1999

By John H. Fowler

The 30th Forum on the Geology of Industrial Minerals will be held in the historical seaside city of Halifax, Nova Scotia, from May 22 to May 27, 1994. The Forum will be co-hosted by the Provinces of New Brunswick and Nova Scotia, two of Canada's East Coast Provinces, both having a long tradition of industrial mineral production. Two previous Forums, the 19th in Toronto in 1983 and the 27th in Banff in 1991, offered delegates the opportunity to see industrial minerals in central and western Canada. The 30th Forum will take you to Canada's east coast completing the picture of Canada's industrial minerals from coast to coast.

Jan 1, 1995

By Alfred C. Maevis

On October 27, 1972, ground was broken for the first section of the Second Avenue Subway, a two track underground rail system that was to extend from the south end of Manhattan at Broad Street, north to the Harlem River at 126th Street, a distance of eight miles. This ground breaking was the culmination of 67 years of planning for an east side subway in Manhattan. Following the successful opening of New York City's first subway on October 1904 there was a mass planning for additional subways throughout the City. In 1905 approval was requested of the Board of Estimate for a First Avenue route and Third Avenue route. The Third Avenue route was approved but when action was not taken to start construction, the approval in accordance with the conditions under which it was given was withdrawn. Further reports and plans for an east side subway, usually to be constructed on Third Avenue, were issued in 1920, in 1922, in 1924, etc. Those of us who had worked on the Sixth and Eighth Avenue subways in the thirites and early forties left to join the armed services of World War II in the expectation that we would return and start work on designing and constructing that east side subway. The reason that much of the thrust in those years was to construct on Third Avenue was that there was a Third Avenue "EL" and business interests of the City were in favor of its demolition. This demolition was accomplished in 1955 so one of the incentives to construct on Third Avenue was removed; but an east side subway was always part of the master plan of the City.

Jan 1, 1976

By Wern-ping Chen, Joseph Pratt, Thomas G. Brueckner, Tracy K. Lundin

To address and mitigate discharges from combined sewer overflows in the Providence, Rhode Island area, the Narragansett Bay Commission completed a comprehensive Combined Sewer Overflow (CSO) Facilities Plan in 1993 which included a series of deep rock tunnels. Since completion of preliminary design of the program in 1994, the program has been reconfigured in response to the Environmental Protection Agency’s (EPA’s) new CSO policy. The currently proposed system consists of a deep rock tunnel with two tunnel stubs which will provide230,000 cu m (62 million gallons) of storage at depths of up to 90 m (300 ft). This paper discusses the revised 5 km (3 mile) long deep tunnel system.

Jan 1, 1999

By A. J. Stewart, R. L. Shufflebotham, D. W. Ferguson, T. L. Page

The Inter-Island Tunnel is a 7.7 kilometer (25,160 foot) long by 3.5 meter (11.5 feet) diameter concrete lined tunnel through the Cambridge formation below Boston Harbor. Constructed as part of the Boston Harbor Project, this tunnel will bring untreated wastewater from the MWRA’s South System headworks facility at Nut Island in Quincy, MA to the new Deer Island treatment plant. A myriad of problems delayed the construction of the tunnel. These problems included salt water inflows of over 22,000 liters (5,812 gallons) per minute, a major fire in the access shaft, weak rock and soil collapsing on the tunnel boring machine, and hand mining operations.

Jan 1, 1997

By Deepak Malhotra, Robert Dorfler

Modern engineering mill design has been refined over the years to the point where detailed ore and process specification criteria can be developed In the engineering design phase of the project. The plant Is then built to the detailed criteria and performance acceptance tested by the owner to see if the as-built mill meets the criteria, This performance testing is critical to the owner; the test must be systematic with sample collection coordinated throughout the plant. Despite the availability of systematic approaches to plant development, the new plants often fall short of design criteria. This paper discusses the key Issues a Project Manager/Process Engineer should Implement to ensure that plants meet design criteria.

Jan 1, 1991

By Gary A. Almeraris, Thomas F. Peyton

This paper describes the innovative procedures employed during the construction of 3 deep shafts within the confines of New York City. The shafts, which varied in diameter from 1.8m (6ft) to 7.3m (24ft) and had an overall depth of 199m (650ft), were excavated by both mechanical and conventional methods. These were subsequently concrete lined, clad steel riser pipes installed and associated surface structures were constructed. Tricky surface rock blasting coupled with the unearthing of unexpected obstructions caused constant uncertainty during the excavation phase. In addition, the necessity of handling men and material in restricted yet deep openings required the development of a safer and more productive shaft construction procedure.

Jan 1, 1989

By Dipak D. Shah, Sajjan K. Jain

An interceptor sewer, 2103 linear meters (6900 Ft), 1.52 meter (5 ft) in nominal diameter, is installed by a direct pipe jacking system utilizing a remotely controlled fully automatic slurry shield machine called "Unclemole". The system involves placement of custom designed fiberglass pipe with Unclemole. The sewer alignment is along a heavily travelled thoroughfare in Staten Island, New York with invert varying from 20 meters (65 ft) to 28 meters (92 ft) beneath the road surface, and passes through soils of Glacial and Cretaceous origin. Dewatering was carried out at the jacking and receiving pits. Details of ground conditions, the pipe jacking system and method, and tunneling experiences are herein described.

Jan 1, 1991

By ev, Ze&apos Reches

The growth of networks of shear fractures is explored in a series of experiments with samples of wet clay. The samples are subjected to plane strain deformation in a rigid apparatus. The individual fractures observed on the upper surface of the clay samples grow longer by three mechanisms: in-plane propagation, off-plane propagation and coalescence. New, active fractures cut and displace older, less active ones. The lengths of individual fractures display lognormal distribution in most cases and power distribution in fewer. The calculated length parameters in the experiments, as well as in three field cases discussed here, suggest that the fundamental parameters in fracture analysis are the normalized cumulative length and the length of the shortest fracture measured.

Jan 1, 1986

By Ulf Marklund, Stig Markstrom

Pioneering work with pilot scale autogenous grinding started in Boliden 1956. From 1961 to 1991 eleven fully autogenous grinding (AG) circuits have been installed at various concentrators within the Boliden company. A compact two-stage grinding system was de- signed in the beginning of 1970s. The system included a pebble extractor which feed the secondary grinding stage with grinding media. The APC grinding system (Autogenous/Pebble/Crusher) is a further development of the AG concept. A new design of the Boliden pebble extractor together with improved control strategy make the performance of the APC system suitable to almost any ore quality. The Boliden AG concept is probably the most cost efficient grinding system of today.

Jan 1, 1998

By Kenneth R. Miller

Surface mine equipment operators in the Campbell County region of Wyoming's Powder River Basin have found new ways of solving old problems. Technology, experience, competitive pressures and an increasing grasp of economies of scale have driven mine operators, equipment manufacturers and suppliers to specialization of applications. In economic terms, today's coal price of $4.95/t ($4.50/st) equates to $2.53/t ($2.30/st) in 1980 terms - an incomprehensible value at that time. This article describes some examples of change and adaptation made by Powder River Basin coal operators in overburden stripping equipment and techniques. It focuses on the evolution of the design and use draglines, shovels, trucks, scrapers and dozers.

Jan 1, 1998