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By John E. Appleby

Grupo Acera, HYLSA originated in 1942 when Hojalata y Lamina began operations to supply steel strip for the Cuauhtémoc Brewery, the parent company. Production began in April, 1943 with growth accelerated because of World War II. By 1948 the company was producing its own steel from electric furnaces charged with scrap iron. Further expansion was hampered by the fluctuations in availability, price and quality of scrap iron. As a result, a search was made for a suitable process to enable HYLSA to satisfy its need for a reliable source of feed for its steel-making facilities. Their relatively low iron requirements at the time did not justify the very high capital investments required using the conventional blast furnace method. Processes which by-passed the blast furnaces were very much in their infancy and were not commercially tested. HYLSA then undertook an investigation of the direct reduction processes, knowing full well that much larger companies in other countries had investigated several processes but their work had not established a trend toward direct reduction or any particular process. However, after much effort and persistence HYLSA arrived at a process which suited their conditions. By using Mexican iron ore and natural gas they developed the now well-known H. y L. Process to produce sponge iron. Concurrent with the start of investigations which led to the H. y L. Process, HYLSA began an exploration program for a suitable source of iron ore. Thus in 1951, Cia. Minera Las Encinas, S.A. was formed, culminating in the development of the ore bodies near Pihuamo in the State of Jalisco. Mining commenced and ore was

Jan 1, 1971

By W. G. Pariseau

This paper is concerned with the problem of calculating ground movement that occurs as a consequence of mining. Solution to this problem is straight forward in principle but rather complex in practice. The complexities of the problem arise from the ever present constraints of technology and economics. However, the identity of these constraints is often obscured by a faulty understanding of the fundamentals of the problem and a lack of appreciation of current computational capabilities and costs. As a consequence much time and effort are sometimes wasted on gathering information that is of little direct value to ground control programs while important input data are neglected. This paper therefore reviews the essentials of the process of formulating the ground movement problem. Emphasis is upon application to longwall mining, although much of the discussion applies to other mining methods as well. In many instances, the hardrock term stope could be substituted for longwall panel because the fundamentals of the problem are independent of the excavation dimensions and numerical values of rock properties. The latter affect the outcome of a calculation, of course, but not the underlying formulation. Only the major features of the problem are discussed in this brief review. The objective of the discussion is the generation of a reliable basis for developing a technically sound ground control strategy. Any rational ground control strategy must be consistent with basic physical laws. For example, under static conditions, equations of equilibrium must be satisfied. Operational, that is, tactical, details may vary widely with local conditions, but the basic approach must be based on physical laws. The alternative empirical route is intrinsically unreliable and unnecessary as well. Empirical descriptions of ground motion caused by mining including recent statistical curve fits to specialized data sets (for example, surface subsidence data) as well as antiquated "theories" of ground pressure and so forth, however dignified with mathematical formulas, are hardly worthy of the label "theory". Extrapolation of statistical data is always accompanied by rapidly diverging confidence limits, while empirical equations simply lack predictive capability under circumstances even slightly different from those of the original development. For example, applications of surface subsidence curves generated empirically in the United Kingdom to coal mines in the United States generally result in considerably greater subsidence and wider subsidence troughs than actually observed. Locally, empirical criteria for specific ground control actions may be made practical through trial and error, but such tactics are no basis for the development of a general ground control strategy. In this regard, it is worthwhile to recall the traditional scientific distinctions between speculation, hypothesis and law, between the empirical and the proven.

Jan 1, 1982

By Jorgen Elbrond

The calculation of open pit operations' capacities has been the subject of many studies using computer simulations. The common problems of simulation are that if one desires a realistic picture of an operation the programming work becomes long and expensive and that the program requires a large computer and long time to run. The method presented in this paper overcomes these problems by using a straightforward calculation procedure. It is based on the queuing theory's simple formula for waiting time in a closed circuit and uses a system of correction factors, which reflect the loading, travel, and dumping times' relative variabilities and which have been found by 1) mathematical analysis and 2) simulations of basic circuits. The method includes the main parameters of the operation: numbers, sizes and operational availabilities of trucks, shovels and dumping point, distribution of the production over shovels, trucks' loading, travel (loaded and empty) and dumping times as well as their variabilities, shift's composition. The procedure models: the average duration of a complete truck cycle during stationary and non-stationary periods during the shift as a function of the number of trucks in the circuit, the composition of the average 100% operated shift, the simultaneous probabilities of operationally available shovels and trucks and the distribution of shovels and trucks according to production and cycle times. The procedure can be programmed for a small computer and requires only short computing time, which makes extensive studies of various parameter combinations practical to carry out. The development of the method is an extension of previous work by Morgan and Peterson {1}, who by simulation established the relation between the match factor (which is the ratio between the sum of one loading time pr truck in the circuit and the complete net cycle time) and the shovel's efficiency, and by Hayes, Splaine and Whitaker {2}, who established this relation from a large number of observations in the Nchanga pit in Zambia. The present method establishes this relation by a straightforward calculation procedure. Theoretical solutions to some situations are found in the litterature on the queuing theory. The papers {3},{4} and {5} give solutions to situations, which fall outside those encountered in the shovel-trucks circuit. These solutions together with simulations of in-termediary situations have been used to establish an interpolation procedure for the correction factors to be applied to the waiting time formula in order to cover the situations encountered in practice.

Jan 1, 1977

By G. S. Austin

New Mexico produced 83% of domestic potash and 27% of domestic consumption in 1992. The potash industry of New Mexico produces sylvite (KCI), langbeinite (K2SO4-2Mg(SO4)2), and artificial K2SO4. Average sylvite grade in New Mexico today is about 14%. The average grade of langbeinite is 8-10% Kp. Commercial potash occurs in the middle or McNutt Member of the Salado Formation (Upper Permian Ochoan Series). The 120-m-thick McNutt Member dips about 1° east and contains 11 of 12 potential ore zones in the Salado. The mineralogy and proportion of clay minerals, up to 7% of the ore, influence optimum milling procedures and ore grade cutoff.

Jan 1, 1994

By J. R. Walls

The United States potash industry had its beginning in the early Colonial days. Potash was initially manufactured by leaching of hardwood ashes in large iron pots. Production of potash was recorded as early as 1631 in New Hampshire, and in Maine a few years later. According to the census of 1850, the production of potash was America's most thriving chemical industry and, at that time, 569 plants were reported producing potash from wood ashes. Interest in potash was so great prior to the 1800's that the very first United States patent, signed by George Washing- ton, was granted for the production of potash on July 31, 1790. A new era for the production of potash began when potash was discovered by the analysis from a brine well in 1839 near Stassfurt, Germany while exploring for salt. The predominant use of potash at that time was in the chemical industry rather than agriculture. The discovery, by Justice von Liebig in about 1858, that potash salt contributed greatly to the essential plant food in soil opened up an enormous potential market for a suitable potash material.

Jan 1, 1985

By Ernest Hucke

This paper will cover basic pneumatic and electronic sensors, transducers, transmitters and their application in the Mining Industry.

Jan 1, 1965

By Ihsan Berk Tulu, Mustafa Can Suner

The synthetic rock mass (SRM) approach and discrete fracture network (DFN) model, generated from the field surveys, are novel methodologies to study fracture rock mass behavior. In this paper, SRM and DFN methodologies were used to understand the influence of natural fractures on the mechanical response and failure mechanisms of stone mine pillars. First, a multi-stage up-scaling procedure with the homogenization process is established. Later, a stochastic sampling process on the SRM model to have further insight on the stone mine pillar mechanics is performed. Two-dimensional Universal Distinct Element Code (UDEC) is utilized to represent intact rock with the Voronoi-Trigon discretized blocks and to capture fractured rock mass behavior. The laboratory-size limestone mine rock specimens are systematically up-scaled to the average width of the field-size stone mine pillars. Then, the DFN model, generated from field data, is sampled to construct the SRM of the field-size pillars. By doing so, the effect of discrete discontinuities on pillar stability is studied by assessing the pillar strengths and failure mechanisms in various width-to-height ratios.

Jul 8, 2022

By Angus Maxwell, Jacob Grasmick

As the tunneling industry continues to adopt Tunnel 4.0, digital twins of the tunnel construction site are becoming standard requirements for tunneling projects. However, the benefits of these remain unproven to many practitioners. The paper discusses the various implementations of digitalization and describes efforts to combine all data types to analyze the relationships between influences, predictions and performance in a single digital platform. This includes data pertaining to investigations, design, construction, monitoring and post-construction asset performance and management. Based on 16 years of global tunneling projects the paper aims to quantify the tangible and intangible benefits of such systems. Using a number of real examples, the paper describes where opportunities were taken and where they went unrealized. Challenges and considerations for both procuring and developing these digital twins are also discussed.

Jun 13, 2021

By William R. Bush

This paper is a presentation of findings based upon an econometric model of the world zinc industry. The model was developed as a simple but useful aid for long-run forecasting and planning purposes. A structure was developed for both simulating real zinc price effects on production and consumption, and for forecasting long-run annual zinc prices and supply/ demand levels. Moreover, a methodology is provided to incorporate the effects of: (1) historic technological advances in zinc supply, and (2) the development of the competitive plastics industry. Finally, reduced form equations are used to generate ex post forecasts to evaluate the model's performance.

Jan 1, 1979

By B. W. Stunkard

Hibbing Taconite Company is located by the cities of Hibbing and chisholm near the center of the Mesabi Range, approximately 169 km (105 miles) from the Canadian Border. The plant site is equidistant from these two communities, about 6.4 km (4 miles) from each. A 169 km (105 mile) railroad connects us with the port of Superior, Wisconsin, where the pellet production is loaded into lake carriers for lower lakes destinations. Immediately to the south of the mine area is the world famous Hull- Rust-Mahoning Mine which produced more than 700 000 000 million tons of red ore between the years 1893 and 1973.

Jan 1, 1979

By W. Hennig

Efforts to define sustainability indicators are continuing in the mineral extracting industry and sector research institutions. Comprehensive ‘sets’ of economic, ecological and social sustainability indicators for the minerals industry are a necessary precondition for rationale-based negotiations with stakeholders from society. These tools alone, however, will not suffice in a delicately balanced economy-ecology -social well-being equilibrium with ever shifting valuation of different variables. Individual interests and emotions and also ideologically motivated positions of diverse stakeholders are gaining momentum. The minerals industry therefore has to develop beyond the rational pro-arguments for mining in the form of sustainability indicators also proactively its ‘soft skills’ to deal with expectations, fears and outright anti-mining bias, if it wants to retain the ‘social licence’ to continue.

Jan 1, 2005

By A. Moharana

A massive slide at Bingham Canyon wiped out a side of the pit and covered the main haul road in and out of the pit. All pre-slide mine designs and schedules were no longer valid. New designs and schedules needed to be developed quickly to provide management with information regarding the immediate post-slide production potential and the time needed to ramp back up to full production. At the time of the slide, an effort was already underway to convert Bingham?s in-house Medium Term Scheduling Process to MineSight®?s Schedule Optimizer (MSSO). One of the main reasons for doing this was to reduce the time needed to produce Medium Term Schedules at Bingham, which involves a complex shovel-based scheduling approach with shovel productivities based on shovel type and the types of mining cuts to which the shovel is assigned over each planning period. The objective of the schedule was to maximize shovel usage, satisfy mill feed requirements of four SAG mills with variable milling rates, and have flexibility in setting truck constraints. This paper will describe how the new MSSO-based mine scheduling process met the challenge of producing new schedules for Bingham in a minimal amount of time.

Feb 23, 2014

By J. C. Danza Errico

The bauxite deposits on the Pocos de Caldas Plateau in the state of Minas Gerais, Brazil, were formed by the differential weathering and leaching of alcaline rocks in a ring structure. Their action on steep topography formed heterogeneous ore posture and chemical grades. Variographic analysis of several of these deposits show nested structures that are probably related to ore genesis. Kriged ore reserves estimation are presented with emphasis on the data pro cessing method that was employed. Programs were written in APL. Its intrinsic use of matrices contributed to faster programming and less computer time. In many cases looping was eliminated. The high resolution graphic resourses of APL. workspace facilitated programming of variogram analysis, fitting, and regularization. APL sub-routines are presented for variogram calculation and kriging.

Jan 1, 1986

By Rameshwar Sah, PK GHORUI, LR SINGH, SIVALINGARAJU BARISETTY, SHYAM YADAV

Fly ash is a by-product generated by the combustion of coal in thermal power plants. Its disposal is a major environmental concern for these power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, a substantial quantity remains unutilized. Bentonite is commonly used as binder in the micropelletization of process waste to attain the mechanical strength required for handling and transportation. The present paper deals with the partial replacement of bentonite with fly ash in the micropelletization process without affecting the quality of the micropellets. The mechanisms of both the binders are discussed. The bonding of particles by bentonite is a physical mechanism, while fly-ash bonding is a chemical mechanism. Silica and alumina are the major constituents present in fly ash along with lime. In the presence of water, the alumino-silicates and unhydrated lime present in fly ash undergo a pozzolanic reaction and form cementitious bonds, which hold the particles together. Use of fly ash as alternative binder for bentonite has cost benefits besides providing a better utilization option for fly ash.

By Charles V. Riley

While the late 1960's are known as the years of the public recognition of impending environmental crises, the 1970's will be known as the decade of public concern for improving the quality of that environment. One of the present major environmental concerns is the temporary disturbance resulting from coal surface or open cast mining. To realize that this concern will continue in the future, one need only observe the daily news media. Increasing energy demands in the U.S., a doubling of electrical power consumption each decade during the present century, and the projected needs for the remainder of the century are indica¬tions that coal surface mining as a major extractive industry will continue. Coal and lignite, prime energy resources and extremely abundant in these United States, in the face of seemingly limited gas, oil and uranium reserves, are both destined for expanded future use. Presently some extremely serious techno-logical and environmental problems are associated with the develop¬ment and use of nuclear power. It is true that the extraction and use of coal as an energy fuel poses disruptive problems for the environment, but the solutions to many of the problems are known or can be solved within a reasonable time framework. Certainly our national well-being and continued survival, as a free nation within the world community, automatically dictate the continued use of the coal resource for energy. Concurrently, those engaged in coal surface mining, with the temporary disturbance of the land and water resources, must also realistically conclude that public concern for maintaining and improving the quality of the environment will not diminish. Although as ecological, economic, social and aesthetic elements

Jan 1, 1972

By R. H. King

This paper describes the results of an underground coal mine trial installation of a shielded trailing cable. The cable was a three conductor, round, type SHC-GC, and was installed on a shuttle car in a conventional room and pillar mining section. The purpose of presenting the information is to prepare mine operators for proposed legislation that will require shielding on low-voltage trailing cables. Specifically, machine modifications are required to cable reels, packing glands, and couplers. Cable splicing is not as complex as expected but additional materials are needed in the kit and splice training is necessary. Even though shielding will cause some problems for the mine operator, it can reduce the hazard of electrical shock to mine workers. This paper will present information that mine operators can use to solve most of the problems that will be encountered if they are required to install shielded cables. The in-mine evaluation was funded by the U.S. Bureau of Mines.

Jan 1, 1980

By R. T. Torrie, J. R. Mernagh, D. B. Chambers

l, INTRODUCTION Uranium mine and mill workers are exposed to external gamma and beta radiation fields from radioactive ore. In the past the average uranium content of ores mined in the United States and Canada ranged from about 0.1% to 1.0% U308 with pockets of much higher grade ore. Holiday (1973) reported that radiation surveys in the U.S. uranium mines found mean gamma "radiation rates ranged from 0.20 to 0.70 mrem/h. Such radiation rates cause relatively insignificant exposures." Others also concluded that the external gamma radiation fields associated with uranium mining did not result in significant worker exposures (Federal Radiation Council, 1967; Simpson, S.D. [et al], 1959) Gamma exposure levels in most modern-day Canadian uranium mines are reported to be low with average annual exposures estimated to be less than 1 rem/a (Frost, S.E. [et al], 1981). However, two developments are taking place which affect the potential significance of external radiation fields in the uranium mining environment. The first development stems from the most recent system of dose limitation developed by the ICRP which is intended to limit the workers' overall risk from exposure to ionizing radiation through the adoption of a sum rule (ICRP 26, 1977) which combines external and internal radiation exposures. In the case of exposure to radon daughters the sum rule will have the effect of reducing the annual exposure limit below the recommended limit by an amount that depends on external radiation and other sources of internal exposure such as the inhalation of ore dust (ICRP 1980). The Atomic Energy Control Board of Canada (AECB) is reviewing this subject and is expected to produce its recommendations shortly. Irrespective of the form of the sum rule eventually adopted by the AECB, it is clear that the net effect of the sum rule will be a collective reduction of the individual dose limits for individual exposure pathways. The second factor is the increasing development of high grade uranium deposits in Northern Saskatchewan. Some of these ore bodies have an average ore grade of 1% to 5% U308 or greater. Since the potential external radiation fields increase in proportion to the ore grade, it is apparent that increased effort in radiation protection planning is required in order to develop safe yet workable methods for mining and milling such ores. This paper is intended to provide information which can be of assistance in the formulation and development of a mining and milling plan. The principal focus of the paper is source identification and the design of radiation protection measures to limit external gamma radiation exposure. The exposure of workers to external beta radiation fields is also discussed. The paper is organized as follows: - Section 2 deals with source characterization. - Section 3 discusses the effects of finite source size and distance (i.e. geometry effects). - Section 4 presents selected data that are useful in evaluating shielding requirements. - Section 5 discusses the potential beta radiation fields. - Section 6 discusses practical data requirements for worker exposure scenarios. - Section 7 presents a variety of work exposure calculations. - Section 8 is a summary of this paper. 2. SOURCE CHARACTERIZATION This section develops the basic formulae for estimating the fluxes and doses from external gamma radiation. The calculation of the radiation flux due to a distributed source (i.e. a linear, area or volume source) as a function of distance assumes that any distributed source can be treated as a summation of point sources. [ ] Uranium ore contains radionuclides from both the decay chains of U-238 and U-235. In this paper the radioactive daughters are assumed to be in secular equilibrium with the uranium parent. (If natural thorium were present in the ore in significant quantities, the gamma rays originating from Th-232 would have to be added to the gamma rays from the uranium series). In all, there are over 50 separate gamma rays (as well as alpha and beta particles) emitted from the U-238 and U-235 radioactive decay series (USHEW 1970). The total

Jan 1, 1981

By Ewald H. Kurt

The story of America's progressing standard of living is the story of machines. The automobile, the airplane and the telephone for example have made our transportation and communication systems what they are today. Even they depend in turn on another machine -- the rock drill. By making it possible to economically mine and quarry minerals in large quantities, this versatile machine supports virtually every American industry relying on the earth for its buried raw materials. And, like all machines, the rock drill's mechanical evolution was stimulated by production demands placed upon it. All percussion drills are mechanized versions of the original drilling unit -- man, Figure - illustrates a double jack team at work before the turn of the century. The man with the sledge hammer is the impact device while the man sitting is the rotation mechanism and feed motor. The first drifter drills (Figure 2) performed the same function but with increased mechanical efficiency. A piston controlled by a valve produced impact. A built-in ratcheting mechanism provided rotation and a hand-cranked screw provided feed thrust. As the industrial revolution proceeded into the twentieth century, the demand for raw materials stimulated refinements of all recovery machinery, including rock drills. As drills became heavier and more powerful, a mounting (or carrier) had to be provided to move the drill from hole to hole. This resulted in the development of the wagon drill (Figure 3). Propelled by muscle power, the wagon drill was for years the standard tool of the surface drilling industry (Figure 4). As drills penetrated faster and as labor increased in cost, the time consumed in nondrilling peripheral operations had to be

Jan 1, 1977

By H. W. Breathitt

World demand for phosphate rock has increased significantly in the past fifteen years. Prior to the early 1960's, most of the world production was obtained from Florida, North Africa, and Kola. As the 1960's arrived, new mines in North Florida and Eastern North Carolina, as well as expanded production in the Western United States, .increased domestic production. Many new mines overseas have also become significant. This includes countries such as Senegal, Togo, Israel, Spanish Sahara, and Jordan. Limited production, often as by-products, has been noted in South Africa, Brazil, and other countries. In recent years, and even recent months, we have learned of many new areas being considered as potential sources of phosphate rock. This includes Australia, Saudi Arabia, Mexico, Colombia, and Brazil. Many other developing countries have discoveries and are considering their new deposits, often with difficult beneficiation problems, as potential sources of phosphate. These factors all relate to expanded world, population and the demand for more fertilizer products to produce food. In this paper, four areas of the world with different types of phosphate deposits are briefly reviewed to contrast the ore beneficiation problems to Florida procedures--long considered the "standard" of the industry, at least for most of the United States' domestic production. Agrico has three large operating mines in Florida with total production capacity exceeding seven million tons per year. Here, pebble phosphate (+14 mesh material) is produced without the use of flotation, whereas all of the material finer than 14 mesh is subjected to flotation beneficiation to upgrade into high grade concentrates.

Jan 1, 1977

By J. W. Cooksley

Pyrometasomatic zones are a type of replacement deposit, normally in a carbonate rock unit, which consists of a zoned, coarse-grained, generally iron-rich mixture of calcium and magnesium silicates. These zones or rock masses are also called ?skarn,? and ?tactite?. They are formed as a result of the interaction of a shallow intrusion of magma with a carbonate or calcareous host rock and are considered to be of hydrothermal origin. Three environments of pyrometasomatic deposits are depicted in Figure 1. Of course, the interaction takes place at high temperatures. Pyrometasomatic zones are categorized as calcic or magnesian, depending on whether the intrusive interacts with a limestone or a dolomite. Common pyrometasomatic zone minerals are garnet, epidote, quartz, calcite, wollastonite, actinolite, hedenbergite and diopside. Pyrometasomatic zones are of considerable economic importance because they contain ore deposits of tungsten, molybdenum, copper, lead, zinc and iron. According to Rose and Burt (1979), the chronological sequence in the formation of a ?typical? pyrometasomatic deposit is as follows: 1. Shallow intrusion of magma at 900-700°C into carbonate sediments.

Jan 1, 1981