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By M. Schlegel, J. A. Villa Mena, R. E. Vivas

ArcelorMittal, headquartered in Luxembourg, is one of the world’s largest steel and mining companies. It supplies steel to industries such as automotive, construction, and energy, with a strong emphasis on sustainability and innovation. The company employs about 125,000 people and, in 2024, produced 42.4 million tons of iron ore and 57.9 million tons of crude steel across 15 countries. Its mining operations span Canada, the United States, Mexico, Brazil, Ukraine, Bosnia and Herzegovina, Kazakhstan, and Liberia, focusing on iron ore and coal extraction to support steel production. This study examines Peña Colorada, one of Mexico’s largest iron ore mines (a joint venture by ArcelorMittal and Ternium). Facing declining ore grades, Peña Colorada adopted Hexagon solutions to uncover and capture project value. A comparison of two Life of Mine (LOM) plans from 2012 and 2016 (before and after implementing Hexagon solutions) shows that between 2019 and 2023, Peña Colorada reduced actual waste by 26% (compared to 2012 LOM) and 19% (compared to 2016 LOM). LOM Plans are generated yearly, and each time, opportunities for reducing mining waste were identified, evaluated and implemented. The key driver was schedule optimization using Hexagon MinePlan Schedule Optimizer (MPSO). This reduction means less waste transported to disposal sites, resulting in fewer hauling equipment operating hours, lower fuel consumption, and reduced carbon emissions.

Feb 22, 2026

By Erich J. Jacob, Volker O. Meldner

INTRODUCTION Our company has made persistent efforts to utilize the very latest cost-saving technology in tunnel design and construction. However, we were relatively late in joining the clan of slurry shield tunnelers. The challenge came in 1973, when our company was low bidder on a major sewer tunnel in Hamburg, West Germany. The tunnel was to be driven under the harbor region through coarse and fine sands with up to 60 ft hydrostatic head of water. Outer diameter was 15 ft, and length was 2.9 miles. This contract appeared right to enter the new field of slurry face tunneling. We gathered a design-engineering team to develop the machine, called it "Hydroshield", and used it on the project. The good performance of the prototype machine encouraged us to improve and modify the equipment design. The very latest model is now in use on a subway tunnel in Antwerp, Belgium. This tunnel is 21 ft outer diameter and 2.4 miles in total length. In terms of excavated volume it is the world's largest slurry shield contract. While the drive is still in full swing, we are currently preparing for 3 further Hydroshield applications, with diameters ranging from 12 to 32 ft. This paper describes the Hydroshield's salient design features, operational characteristics, construction reliability and performance levels, as experienced in West Germany and Belgium.

Jan 1, 1979

By Christopher Nelsen, Daniel Dobbels, R. Zachary Hollenbeck

Recent major floods have inundated Historic Ellicott City, Maryland, resulting in loss of life and property damage. Howard County, Maryland, has developed the Ellicott City Safe and Sound Plan to mitigate the risk of flash flooding in the Historic District, including a proposed stormwater conveyance tunnel. Challenges to overcome include thick zones of saprolite along the alignment, multiple near-surface structures, and minimal rock cover under an active railroad, while minimizing impacts to the public and historic structures. The project will also pursue recognition through the ISI Envision verification process.

Dec 1, 2022

By Robert Sturk, Knut O. Halvorsen

"INTRODUCTION AND BACKGROUND The world needs visionary people to break new ground and bring development forward. The human race has an inherent power and lust to explore and push borders, but also to connect and bring people together. Transport of people and goods has through history been a key factor to develop societies and increase collaboration between people and regions. Today, in the era of globalization, efficient transport systems are still vital for further development. Often, ideas of bold projects, like long bridges or tunnels, have been raised long before those projects are realized and actually built. This shows that visions must gradually be transformed into feasible business cases and sustainable political solutions. In some cases also technological development is necessary to make visions come true. Isambard Kingdom Brunel, indeed a visionary engineer, completed the oldest underwater tunnel in the world when the Thames Tunnel in London was opened in 1843. This tunnel is still in operation and now part of London’s rail transport system. Another milestone for the tunnelling industry was passed when the 54 km long Seikan tunnel in Japan was opened in 1988 after more than 15 years of construction. This tunnel is presently the world’s longest railway tunnel. Together with the 50.5 km long Channel tunnel between the UK and France, which has the longest undersea portion 37.9 km, they constitute examples of pioneering engineering projects that bring the industry forward. In 2016, the Gotthard Base Tunnel will be opened and then becomes the longest railway tunnel in the world with its 57.1 km. The trend is obvious that tunnels throughout the world are getting longer and longer. The Brenner Basis Tunnel presently under construction will yet again break the record being 64 km long. Presently, a number of even longer tunnels are planned and under design, some of these also have very long subsea portions, e.g. Bohai Straight Tunnel (123 km), Irish Sea Tunnel (around 100 km) and the Helsinki – Tallin fixed link (approximately 90 km). Northern Europe sees an increasing demand on efficient transport corridors to meet the growth of freight transportation between the Scandinavian Peninsula and central-Eastern Europe. Sustainable solutions will be required, and a shift from road/maritime transports to rail is imperative. Consequently, this paper describes yet another visionary project, a fixed railway link between Sweden and Germany, the Shortcut, to enhance traffic between these regions and to make it greener. It is true that this project still requires some work from politicians, economists and engineers to be realized, however, building a 100 km long tunnel under the Baltic Sea may become reality sooner than we think."

Jan 1, 2016

By A. R. Bell

Rio Algom Limited are currently undergoing a major expansion of their mining operations in the Elliot Lake area. To date this has involved the increase of output at the Quirke Mine from 4080 to 6350 tonnes per mill day (4500 to 7000 tons), the rehabilitation of the Panel Mine to produce at the rate of 2990 tonnes per mill day (3300 tons) by 1980, and the rehabilitation of the Stanleigh Mine to produce 4540 tonnes per mill day (5000 tons) by 1984. In addition, the planning for the rehabilitation of the Milliken Mine to produce 4990 tonnes per mill day (5500 tons) is now underway. This major expansion is taking place at a time of increasing awareness of occupational health matters and has involved very high capital expenditures and detailed planning related to the ventilation system to endeavour the provision of an acceptable environment. The paper discusses the ventilation systems, established and proposed, and relates them to historical and current data on mine air contaminants.

Jan 1, 1980

By Jim Buckley, Ryan Sibley, Scott G. Giltner, Thomas Pallua, Joe Schrank, Robert Cidlik

Because of variation in rock type and site conditions, it is important to create site-specific prediction models for peak particle velocity (PPV) and understand instrumentation mounting locations to better interpret the readings provided following blasting operations. The Atlanta Airport is expanding the section of underground tunnels for its Plane Train people mover, and drill and blast operations were determined to be the suitable method of excavation for the project. Extensive work was done to begin creating prediction models and determining levels of concern based on readings from various types of instrumentation. This paper analyzes the effect of close quarters construction blast vibrations and observed frequency spectrum on existing structures with data from 22 different seismographs mounted in various locations and ground conditions.

Dec 1, 2022

By Barrie C. Butt

The opportunity for an exploration geologist to follow a successful exploration project through the feasibility, financing, construction, development and exploitation phase is rare. In addition, it is not often that the exploration geologist can be present during the mining of a deposit to explain why certain actions were taken or interpretations made and to find out how these interpretations turned out in actuality. At the Woodsreef chrysotile asbestos mine in New South Wales, Australia, mining has been in progress for six years and the writer has been intimately associated with the project during the five years of exploration and the six years of exploitation. The industry is possibly aware of the fact that the Woodsreef Mine has had major production problems, the majority of which have stemmed from the unique characteristics of the ore body and of the fibre. Because of these unique features, a large volume of research has been undertaken by Woodsreef and by other scientific organisations in Australia, England and Canada on the Woodsreef fibre. The answers to some of the problems have negated some semi-sacred concepts of asbestos ore milling and led to the development of new techniques, such as the adoption of microscopic fibre counts as a routine procedure; the modification of accepted evaluation procedures; the development of new machines for dedusting fibres, and to the recognition of a fibre with a unique milling behaviour pattern and, possibly, properties. The problems experienced can be divided broadly into those associated with the geology and those associated with the physical properties of the fibre. It is possible that the same features may manifest themselves in other deposits around the world, and if they can be recognised during the exploration stages a feasibility evaluation may be just that little closer to the actual.

Jan 1, 1978

By Allen Latham

It started' in 1936 when some Dutch adventurers wanted to scale the highest mountain in the South Pacific. Quite by accident, they discovered the Ertsberg, a contact deposit of magnetite laced with chalcopyrite, in a high mountain valley where it had been gouged at by glaciers and finally left as a solitary pillar for its discovery by a geologist who lent purpose to the expedition, Dr. J.J. Dozy. By the-.time a report was published describing the deposit, war had hit the Netherlands. Perhaps again by accident, the report was uncovered in 1959 by the East Borneo Company. At this point, Freeport entered the scene through its vice president for exploration, Forbes Wilson. During the course of a meeting on laterite prospects, the Ertsberg was introduced and he put the wheels into motion for Freeport to join in its exploration. You might, at this point, ask yourself whether you or your company would have taken on a venture to look at a reportedly large high grade copper outcrop in New Guinea, an unexplored land known best for its inhospitable climate, terrain and head-hunters. I heard the chief executive of one large mining company comment sometime back that neither he nor his company would have gotten involved. I won't attempt to describe the trials of the initial exploration expedition that passed through dense-man grove swamps, tropical jungle and across jagged mountains a distance of some 200 miles to get to the Ertsberg in 1960. It should be chronicled by its participants - Forbes Wilson, Del Flint, and John Bowenkamp. Needless to say, the participants relish the experience but wouldn't be among those volunteering for a return engagement. As a result, the Ertsberg changed from a reported outcrop to a mineral deposit containing an estimated 13 million tons with systematic surface sampling indicating a copper grade of over four percent. Moreover, the deposit extended to an indeterminate depth with the possibility of doubling or tripling. reserves well within reason.

Jan 1, 1971

By W. L. Dare

Land use planning is not a new concept in the United States but the emphasis has changed drastically since the early 1960's. Under the old interpretation we tried to expand our frontiers and develop our land, but as society has become more affluent and mobile the demand has grown to preserve those parts remaining undeveloped. There is something of a paradox inherent in this change of emphasis. While affluence has motivated our support to preserve the quality of the natural environment, industrial development is needed to support the affluence. Because we cannot accomplish all of each, sound planning and compromise will be necessary since it is unlikely that, the American people will want to surrender much of their life-style or their awakening environmental concern. Any industrial society, whether a goal reached or an aim yet ahead, is built largely on the use of mineral raw materials and energy, the physical base of nearly all activities and products. The standard of living which is important to us all is growing more dependent upon these minerals, metals, and energy fuels. Although reduction in consumption of raw materials may be acceptable to those at a certain economic level of a society, those who have not reached that level cannot be expected to accept a lowering of their present or anticipated standard of living.

Jan 1, 1974

By M. A. A. de Klaver

Functional Description Figure 1 is a typical flowsheet for a system for solid fuel addition to filter cake. Solid fuel, coal, coal breeze, or charcoal, is fed from a,stockpile to a surge hopper. The solid fuel is metered into a grinding mill. The fuel is dried and ground in a grinding mill. The on-size particles are removed from the mill by air sweeping. The ground solid fuel is separated from the air stream by a cyclone and stored in a surge hopper. The ground solid fuel is then pneumatically conveyed to a small hopper in the balling area. The fuel is proportioned into the filter cake just prior to mixing. An efficient mixer is very important to have a successful operation. The exact flowsheet would depend on a number of factors including what fuel is used, how the fuel is received, and the cnaracteristics of the fuel as received. Availability of floor space in the plant may also affect the flowsheet. For example, drying air may be supplied from the pellet furnace if the grinding mill can be located near the grate, or the pneumatic conveying system and a surge hopper may be eliminated by placing the grinding mill adjacent .to the mixing area. Also, for a multiple line plant, a ball mill rather than a roller mill may be more suitable.

Jan 1, 1980

By Russell Barr

Operational excellence is generally known as a management system integrated across critical functions that is geared towards continually improving operational performance. Functional areas such as health, environment and safety, quality and human resources are the focus of many corporate-wide operational excellence programs. Operational excellence also focuses on improving areas such as customer orientation, employee empowerment as well as process, and systems optimization. It is widely viewed as critical to sustaining business performance improvement. Although it is difficult to find a universally accepted definition, or even common foundation in many respects, operational excellence remains a popular term in the business world. Many organizations have developed their own version of organization excellence, influenced by such individual factors, other similar institutions or even third-party service providers. A mining organization is no different from other organizations in that adopting and implementing effective operational excellence programs can dramatically improve business execution and performance across regional or global interests. This paper brings together various perspectives of operational excellence and reconciles them for a useful composite for the mining industry. While most agree that operational excellence should include normal functions in a manufacturing operation such as production, maintenance and engineering and processes such as quality, environmental and continuous improvement, many other factors for operational excellence seem to vary from perspective to perspective. Thus, programs that manufacturers engage in may seem the same, but may, in fact, be different in key areas. This may affect organizational performance in tangible ways. Management must buy into the company?s definition of operational excellence and be dedicated to achieving it. A review of many of the existing definitions of operational excellence, explicit or embedded as part of a program, seems to yield the following common factors: ? It should help organizations better execute their processes and services. ? It should be geared towards improving quality ? It requires that the various operations should be aligned with the overall enterprise strategy. ? It should be geared towards continuous improvement. A composite of operational excellence definitions suggest that it is: ? Geared towards helping the organization achieve sustained profitability; ? tied to strategic alignment and business objectives; ? tied to solid investment strategies; ? integrated as part of the culture, process, time plan and performance; ? a relevant performance measurement system; ? extended to include all aspects of the supply chain (including external suppliers); ? integrated with health, safety and environmental (HSE) aspects. And, while the pursuit of operational excellence intuitively suggests that businesses should improve, it is very difficult to achieve given the difficult challenges facing companies today. Mining businesses face numerous pressures to perform in a global marketplace such as demand, energy cost, variable cost and pricing fluctuations as well as infrastructure challenges to further confound the environment. Companies generally must look to the following:

Jan 1, 2009

By R. E. Lindstrom

The mineral bastnasite is utilized to describe alternate processes for the extraction and separation of the rare-earth elements by solvent extraction. The rare earths can be acid-leached directly or fused with NaOH before acid leaching. Cerium, the major constituent, can be recovered by fractional precipitation, fractional leaching, or solvent extraction with tri-nbutyl phosphate. The latter process is capable of producing 99.5-percent pure CeO2 at 98+ percent recovery. Lanthanum is subsequently recovered by fractional precipitation or solvent extraction with a nitrogen-based extractant. A 20-stage mixer-settler operation with a primary amine extractant results in a 95-percent pure La203 fraction at 96 percent recovery. Europium is amenable to extraction from most of the remaining rare earths with an organophosphate extractant. Selective stripping of the europium, followed by reductive precipitation, produces high-purity Eu203. Another possibility for europium purification involves the differential extraction of europium with an amine followed by a sub- sequent reducing strip. Separation of the remaining elements is more difficult but can be accomplished with amine or quaternary ammonium extracts. Typical separation factors achieved are 3. 8 for praseodymium-neodymium and 10. 5 for neodymium-samarium.

Jan 1, 1967

By W. Petruk

Mineral liberations that would be obtained by grinding an ore to a specific size can be predicted by analyzing unbroken ore pieces, and mineral liberations in ground ores and mill products can be determined directly by image analysis. Predictions of mineral liberations are made by measuring size distributions and textures of mineral grains by image analysis, and using liberation models. Ground ores and mill products are analyzed to determine the proportion of mineral that is liberated, and the data are used to evaluate mineral behaviour during mineral beneficiation. The liberation data for minerals in a suite of mill products from a circuit are processed by a materials balancing technique to calculate recoveries of minerals in different types of particles throughout the circuit. The liberation-materials balance data define mineral recoveries; define the behaviour of an ore in a concentrator, pilot plant or bench test; and indicate whether recovery improvements are possible and/or feasible.

Jan 1, 1991

By W. C. Hirt

Selective flocculation was used to produce superclean zinc concentrate with minimized silica contamination. Research was carried out on a flotation concentrate from the Jersey Miniere Zinc Company (JMZ) in Gordonsville, Tennessee. The material was first dispersed with sodium silicate and then causticized tapioca starch was used to selectively flocculate the sphalerite, leaving the silica in suspension. This technique has been applied commercially to iron ore beneficiation but has never been used for processing zinc. The feed material assayed 0.45% Si02. Use of 0.56 kg/tonne (1.13 lb/st) of sodium silicate and 0.070 kg/tonne (0.141 lb/st) of causticized tapioca starch resulted in 98.2% zinc recovery in a purified zinc concentrate assaying 66.0% Zn and 0.24% silica. The present target level for silica contamination in JMZ zinc concentrates is 0.3% Si02. This work has shown that selective flocculation offers a potential method for cleaning flotation concentrates, particularly where low silica products are required.

Jan 1, 1993

By D. L. Moellenberg

Under various state laws enacted mostly within the last 20 years, reclamation requirements and standards for hard-rock mining operations have been established virtually everywhere in the western United States. Unlike the uniform and detailed coal mine reclamation requirements under the federal Surface Mining Control and Reclamation Act ( "SMCRA" ) and state programs mode led after SMCRA, the various state law hard-rock mine reclamation requirements are based upon a variety of objectives, and therefore are subject to varying standards from state to state. While the diversity of reclamation requirements complicates the determination of what reclamation measures will be required at any particular mine, there are valid reasons for this diversity. There are dozens of different commodities mined in the United States, and mining methods are different for each commodity. Local natural conditions such as climate, precipitation, geology, hydrology, and biology vary widely across the county. Site-specific conditions also affect mining and reclamation methods. Also, factors such as economics, land use, and environmental protection issues receive different priorities in different states and communities within those states. State reclamation requirements in general provide the flexibility to consider site-specific circumstances, allowing operators to design and engineer the best reclamation measures for each mining site. To the mine developer or manager, reclamation requirements must be translated into design, operational, and closure measures for mine planning. Each of these measures must then be assigned additional costs to be factored into the economic decisions for a particular mining operation. On a broader level, reclamation costs must be factored into decisions such as where to invest in exploration and mine development. The purpose of this paper is to provide a summary of the state non-coal mine reclamation requirements in twelve western states. This summary comparison may be useful as a starting point in considering how local reclamation requirements will impact potential mining costs.

Jan 1, 1994

By Y. J. Wang

Editor's Note: Y.J. Wang's paper appeared in the September Technical Papers section. There were some inadvertent editorial errors in it. So we are reprinting it here. Abstract - This paper examines the ventilation network problem from a view point of solving a system of B equations in B unknowns, where B is the number o f branches in the network. Based on Kirchhoff s current and voltage laws, the solution to the general ventilation network problem must satisfy B network equations. In this paper, the air quantities and control-device pressures are chosen as variables and are grouped into B dependent variables (unknowns) and B independent variables, resulting in a system of B equations in B unknowns. Based on whether their variables are dependent or independent, the network branches are classified into f our types: five d, non-fixed, p-fixed, and q fixed. The ventilation network problem may include all four types of branches. There are .some conditions under which the problem as defined in this manner does not have a unique solution. To have a unique solution, the Jocabian matrix of the equations m us! he nonsingular. It then follows that: • the number of branches with independent air quantities must be less than or equal to the number of chords with respect to a spanning tree; •the subnetwork of branches with independent air quantities must not contain any cutset; and •the suhnetwork of branches with dependent control-device pressures must not contain any cutset. These three conditions must be met regardless of the values for the variables. In addition to the problem formulation, a solution procedure applying the Newton (or Newton-Raphson) method is outlined and illustrated with an example problem.

Jan 1, 1991

By C. Sun

Due to unfavorable geological condition, excessive deformation of mine drifts occurred in a large underground copper and nickel mine. In searching for a solution, a comprehensive underground monitoring program was implemented and the opening convergence and the surrounding rock deformation were monitored. A large number of field data were collected and thoroughly analyzed. The convergence and deformation as function of time and depth were determined and a rock stability index was proposed. Based on the deformation-time and deformation-depth relations, critical deformation times and locations were identified and defined as characteristic values to be used for mine opening and support designs. The characteristic values are critical in the application of two-step supporting system, and the determination of support parameters. The application of the method developed in this study has demonstrated that this practical approach in support design and installation is effective. With the two-step supporting system, a long-term drift stability can be achieved in the mine.

Jan 1, 1998

By P. Massacci

The modelling of phenomena by nonlinear dynamic Systems Theory representations require the specification and identification of suitable models of the phenomenon and the availability of good optimization algorithms to determine the optimal controls. Stochastic disturbances and difficulties of monitoring the process lead invariably, otherwise, to suboptimal performance. It will be shown that an algorithm can be formulated which will simultaneously identify and optimize such a system. The properties of the algorithm will be derived and its convergence to an optimal control proved. Some results of actual applications will be presented and it will be shown how this approach generalizes easily to optimal control of the actual processing system. These results generalize those of optimal learning and input conditioning.

Jan 1, 1991

By Frank C. Stevens

Many changes have taken place in the "World Cement Market" since Joseph Aspdin discovered portland cement in the early 1800's. At the turn of the century, production of cement world wide was a few million tons; today, it is over one billion tons. By 1995, world production is estimated to reach 1.2 billion tons. Cement processing has changed from inefficient, small vertical kilns to large efficient, precalcining kilns, and large automated crushing, blending and grinding systems. Consequently the cost of production has declined in real terms, resulting in significant economic benefits to the general public. In addition, quality and uniformity of cement have increased, strengths have increased, and at least 25% fewer pounds of cement are needed for each cubic yard of concrete. Today, cement moves thousands of miles on the inland rivers and great lakes of the U. S., across Siberia and across the oceans of the world. The volume of cement moving more than a few hundred miles is almost 100 million tons, or 10% of world production. Today, on a per ton basis, it costs no more to move 40,000 tons of cement to the United States from the Western Pacific rim or from Europe than it does to truck cement 200 miles. For example, cement shipped by water from Spain costs $5.00 to $7.00 per ton compared to cement shipped by truck 200 miles at $16.00 per ton. This low cost water transportation has been a major factor for the increased movement of cement between countries. Table 1, Cement Production Summary-World, gives a global picture of production, export and import tonnages in recent years. Figure 1 is a graph showing CEMENT PRODUCTION SUMMARY WORLD WIDE.

Jan 1, 1987

By Kwadwo Osseo‑Asare, Isehaq Al‑Nafai

The hydrometallurgical processing of bastnasite is a well-known process that is used to extract rare earth metals. However, more accurate measures are required to enhance the efficiency of extracting and recycling rare earths. In this work, Pourbaix (Eh–pH) diagrams for La-, Nd-, and Pr-(F)-(CO3)-(SO4)-(Cl)-(NO3)-(C2O4)-H2O systems were theoretically derived to investigate the stability relations during the hydrometallurgical processing of bastnasite. The diagrams for RE-H2O systems show similar trends to the original ones drown by Pourbaix. The stability domains of RE carbonates were presented by RE-CO3-H2O systems with pH range of 4.5–11. In contrast, the diagrams for RE fluorides showed a large stability region of insoluble REF3 (pH ~ − 1.7–12). The decomposition behaviors of REFCO3 were studied by constructing Eh–pH diagrams for RE-F-CO3-H2O system. The stability regions of bastnasite species extend from nearly neutral to basic media (pH ~ 6.5–12). The acid treatment (using H2SO4, HCl, and HNO3) of bastnasite was investigated by constructing Eh–pH diagrams for REF- CO3-(SO4)-(Cl)-(NO3)-H2O systems. According to these systems, REFCO3 can be decomposed at pH ~ 6.5 when treated with H2SO4 and at pH ~ 1.7 when treated with HCl and HNO3 acids. On the other hand, the alkaline treatment of REFCO3 converts it to RE(OH)3 at pH ~ 11. The recovery of rare earths ions was studied with the aid of RE-C2O4-H2O systems which shows a wide stability region for RE oxalates in pH range of − 2–11. This theoretical approach explained the aqueous relations in the hydrometallurgical processing of bastnasite ore and it can improve the practical hydrometallurgical processing of such ores.

Feb 9, 2024