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By Jr. Smith

Silver-gold ratios were studied at the Tayoltita epithermal vein deposit using channel sample, channel sample line, stope, ore body and vein sample populations. The ratios are highly variable among individual channel samples (25:1 to greater than 500:1) with both high and low values randomly distributed within ore bodies and veins. Whole vein ratios for the fourteen most important ore producing structures range from 44:1 to 105:1, and show zonal distribution relative to two small granitic stocks, low values closest to the intrusives. The zoned nature of the deposit suggests that the stocks, apophyses of an underlying batholith of Late Eocene age, were the heat engines which powered the hydrothermal system responsible for ore deposition.

Jan 1, 1978

By R. R. Bhappu

The metallurgical processing industry is in the midst of a hydrometallurgical revolution with mining companies looking for low cost, energy efficient and environmentally friendly technologies for processing sulfide ores and concentrates. The Intec Copper Process is one of the most advanced of these technologies and has the potential to greatly change the way copper concentrates are treated in the future. Specifically, the Intec process has the ability to be built on a small scale and at mine sites while being much more economic than conventional smelting. Intec Copper has constructed a I tonne of copper per day demonstration plant in Sydney, Australia designed to verify metallurgical and operational performance. This paper will describe the process in more detail and provide preliminary results of the process based on the plant's performance. It will also compare the Intec Copper Process with a few of the competing technologies and evaluate the relative economic merits of Intec.

Jan 1, 1999

By Arthur P. Nelson

In opening, I want to thank the program committee and members of the Society of Mining Engineers of AIME for the opportunity to speak to you. Various chapters of AIME this past year have expressed interest in the Federal Metal and Nonmetallic Mine Safety Act. We want to see that interest continue, because the reason for the legislation was the safety and health of the industry's workforce. The Department of the Interior was directed by the Congress to administer the provisions of the Act and is therefore held directly accountable for the success or failure of its intent. We intend to see it succeed. Among other things, the Act does provide for education and training under Section 15. This provision has been implemented and is expanding. However, the responsibility of my office is inspection and enforcement and that is my subject today.

Jan 1, 1973

By Ronald L. Wiegel

In the 2000 page Handbook of Mineral Dressing by A. F. Taggart, the subject of material or metallurgical balances is covered in only six pages of eve-straining type. Although Taggart's work was compiled before 1945, and there has been significant progress since then in most areas of mineral processing, the practicing metallurgist's approach to metallurgical balances remains exactly the same as described in those six pages. There are several portions of Taggart's text appropriate to introduce the subject of this paper which I would like to quote: "Milling Calculations. Computations of per¬formance in milling are complicated by the fact that it is a continuous rather than a batch operation, that the quantities of solid materials handled are large and usually mixed with water, hence difficult or impos¬sible to weigh. Fortunately it is possible to determine many facts concerning perfor¬mance without knowing weights, if the value of various constituents is known in some common unit, e.g., the content of some par¬ticular metal or mineral, or of water, or some ingredient soluble therein, or of par¬ticles of a particular size or falling within some particular size range, or the like."

Jan 1, 1979

By JIACHENG XIE, Juanli Li, Wenyong Du, Tao Cui, Mengyao Dong, Pengfei Huo

The operation of intelligent coal mining in complex geological environment is still unable to realize automation. In order to realize the autonomous cutting of fully mechanized mining equipment and improve coal production, a mining and transportation equipment dynamic advancement path planning method based on spatial kinematics coordinate deduction prediction and real-time correction prediction of coal-rock state identification of equipment cutting current index are proposed. Firstly, the spatial motion law of the mining and transportation equipment is analyzed, and the mathematical model of the spatial motion of the mining and transportation equipment is established. The relationship between the adjustment of the shearer rocker arm and the pose change of the scraper conveyor is determined, and the coordinate deduction model of the spatial advancement position of the equipment is determined, which provides a theoretical basis for the advancement path planning of the mining and transportation equipment. Then, on the basis of the mathematical model construction, combined with real geological data and equipment information, the three-dimensional dynamic planning of the advancement path of the mining and transportation equipment is carried out from the two dimensions of the horizontal advancement direction and the shearer walking direction. At the same time, the relationship between the cutting current index of shearer and the state recognition of coal-rock mass is analyzed, and the coal-rock mass state identification of cutting current and the adjustment of rocker arm model is constructed, and the real-time dynamic correction of three-dimensional path is carried out, so that the planned path can better adapt to the sudden change of real geological environment. Then, using the unity3d virtual reality technology, a simulation system for the horizontal advancement path planning of the virtual mining and transportation equipment is constructed, which simulates the real advancement operation process of the mining and transportation equipment and conducts advancement training. Finally, the dynamic advancement scheme update prediction based on the existing actual cutting but ahead of the actual cutting is realized in the virtual scene, and the optimal scheme is transmitted into the existing prediction cutting system to guide the actual physical equipment mining. The path planning method can control the coordinate position error of the advancing cutting path within 15 mm, which provides ideas for the research on the advancing path planning of fully mechanized equipment.

Nov 22, 2022

By J. H. Gasper

A cost analysis for two alternative contour mining methods is performed to compare their results. The methods evaluated are: 1) Front-End Loader/Truck Haulback and 2) Scraper Haulback. Before performing these analyses, output requirements and equipment needs are found based on integrating geometric limitations with material properties. The final geometric design establishes limits on clearances, congestion problems and grades (with associated running surface materials). All calculations are kept practical, with assumptions clearly stated. The cost analysis is a unique, easily utilized compilation of several different approaches incorporating cost engineering principles. The strengths of each are welded into a cohesive entity once again aimed at practical application. The results are presented in tabular form.

Jan 1, 1992

By K. L. Ludeke

For many reasons it appears that deep-rooted, perennial shrubs offer potential for improved stabilization and provide maintenance-free vegetative cover to harsh sites where perennial grasses have not been successful. The very fact that a drought-adapted shrub has a massive root system that can use moisture from a greater volume of mineral waste soil materials suggests that long-range arid environment resource development may be greatly enhanced by utilization of desirable forage shrubs. An effort is underway to assemble information and plant materials of promising species from many arid regions of the world. Surprisingly, many of the better plants for arid sites are quite high in protein content, and with proper management, breeding, and selection may prove to be very desirable livestock feed. Advancements in arid-land solid waste stabilization hold favorable promise for many industries that mine and mill in arid regions for effective reclamation of disturbed areas. Particularly exciting is the possibility of establishment of high density maintenance-free vegetative cover of climax vegetation that reclaims the disturbed area back to its original land use. Because of high shrub productivity, stabilization potential, nutritional quality, and reclamation success, greater use should be made of shrubs in disturbed land reclamation associated with mining and milling operations in harsh arid environments.

Jan 1, 1984

By C. F. Giermak

Over a considerable period of time great interest has been shown in selective dry concentration of fine ferromagnetic particles, although it is only recently that new permanent magnetic materials have been made available to permit building of such permanent magnetic separators. It is well known that the conventional drum separator does' not efficiently separate fine materials. The centrifugal force on any drum acts in accordance with the particle size and gravity, which may beat varying magnitude-.opposite to the magnetic force, especially when the material is not closely sized. The Magnetic-Mechanical Separator (MMS) is designed for the concentration of fine, unsized magnetic materials where the percentage composition of magnetics to nonmagnetics, or the nature and texture of the materials, is such that its unique agitation and shake-out action with no centrifugal force provides greater efficiency than is obtainable by conventional magnetic separation equipment. This machine consists of a complete double belt conveyor unit with a premagnetizing Axial Pole Agitating Pulley at the feeding end of the lower conveyor belt and a special agitating concentrator magnet above the lower belt of the upper conveyor.

Jan 1, 1965

By William Detty

An architect representing the Atlanta office of the Brick Institute of America periodically presents a slide lecture to interested groups entitled "The First 10,000 Years of Brick". The title signifies the fact that brick, man's oldest manufactured building material, has been around for quite some time and will continue to be utilized by architects and builders in the foreseeable future. This is not to say that the brick industry can rest on its laurels and ignore the competition presented by newer more innovative products. The industry will have to be equally inovative and market oriented in order to maintain its market share of the predicted construction boom between now and the year 2000. The implication is made, however, that brick can be produced under rudimentary conditions and that the desire to use the product has been long standing. In addition, history has sham that there has been plentiful clay available to produce the product. This paper is an attempt to assess the climate in which the brick industry will operate during the next 26 years. An analysis of regulatory conditions affecting the manufacture of the product will be followed by an assessment of the materials environment in which the industry will be operating. These factors are then reconciled with a projected demand for the product to determine the ability of the industry to satisfy future demand for brick. From a mineral point of view this paper will address itself generally to the availability of and demand for clay. However, other than a brief overview of the uses of other specific types of clay, it will concentrate on the clays utilized in the production of structural clay products, specifically brick.

Jan 1, 1974

By Jonathan K. Hrica, Brianna M. Eiter

The ability to identify hazards during a workplace examination is a critical skill for mineworkers to have in order to maintain a safe workplace. While research suggests that being able to successfully recognize hazards requires a complex set of competencies, it is unclear which competencies are most critical to adequately perform a workplace examination. This paper presents a hazard recognition competencies framework as an explanation of the competencies that affect mineworker hazard recognition. To better understand how the industry is selecting and preparing workplace examiners, researchers fromthe National Institute for Occupational Safety and Health (NIOSH) interviewed nine health and safety (H&S) professionals at surface stone, sand, and gravel mine sites throughout the USA. A primary purpose of these interviews was to verify the competencies included in the hazard recognition competencies framework and to understand why these competencies are critical. Finally, the results of this study are presented within the context of current NIOSH research findings related to hazard recognition.

Jul 27, 2020

By Walter B. Hester

All persons and communities that have experienced strong-motion earthquakes are convinced of the importance and complexity of earthquake problems thatmust be solved in order to reduce the personal hazards and property losses to a reasonable minimum. It is also clear that absolute elimination of all risks is impossible. Reduction of existing hazards and precautionary measures which will minimize chances for disaster can be accomplished by realistic appraisal of the effects of recent earth- quakes on modern structures and installations. Localities that have reason to expect so-called strong- motion earthquakes can anticipate these effects by taking appropriate steps. Valid earthquake information can only be obtained from earthquakes. Each earthquake contributes to the body of knowledge by additional facts and by clarification of previous observations. Rational interpretation of the data followed by practical application of the conclusions can contribute greatly to the safety of persons and property. The general public expects the architectural and engineering profession to accept this obligation and render this service. Most earthquake hazards are man-made and arise from the imperfections of the works of man and his failure to anticipate the consequences when the natural characteristics of his environment are ignored. If it is not given to man to prevent such natural phenomena as earthquakes, it is sometimes within his power to control their destructive effects and to reduce to a minimum the toll of life and human suffering.

Jan 1, 1958

By Madhu G. Ranade

A statistically designed pot grate- kiln test program was conducted to determine the agglomeration process variables necessary for increasing the low temperature disintegration resistance (LTD) and reducibility (R40) of magnetite-based Empire acid pellets. The ASTM tumble index and compression strength were to be maintained at an acceptable level. Six process variables, bentonite addition level, preheat time and temperature, firing time and temperature, and cooling rate, were investigated within the constraints of the Empire plant. The bentonite addition level and firing temperature had the largest effect on pellet properties. The results of this program were verified during a pl ant trial. The target firing temperature at the Empire Plant has been decreased for increasing the LTD and R40 of commercially produced Empire pellets

Jan 1, 1985

By D. E. Cameron

The Cannon mine, located in north-central Washington is mining gold hosted in silicified Eocene-age arkosic sediments arrayed along a regional strike-slip fault system. Branches of the Eagle Creek fault have broken the Chumstick Formation into blocks and wedges, and have caused intense deformation of stratigraphy in the mine. Mineralization at the Cannon mine (B-Reef) and O-Reef (L-O mine) is a bulk silicification with high grade cross-cutting veins containing principally electrum, silver sulfosalts and pyrite in a gangue of quartz, adularia and calcite. Orebodies have very irregular shapes, but tend to follow stratigraphy and high-angle pre-mineral fault breccias and splays developed adjacent to the major faults. Both B-Reef and O-Reef occur at significant bends in the regional trend of major fault strands. Mean gold grades decrease upward from near sea level to the 300 m elevation at the Cannon mine. A new discovery, the A-Reef is hosted by a moderately dipping structure which is at a low angle to bedding. Fluid inclusion studies of B-Reef ore zones indicate dilute ore-bearing fluids boiled at temperatures between 185 and 2850 C at a depth of 1 km. Many ore zones are bounded by sheared mudstone and claystone and a much broader halo of argillic alteration comprising illite, smectite and sericite. Trace and major element analysis by ICP-ES for 33 elements, LECO for S, Hg by CVAA and gold by AA-FA shows dispersion patterns hundreds of meters outward from the known orebodies in the Cannon mine. Geometric mean comparisons, hierarchical R-mode cluster analysis and single element spatial plots show that Hg, As, Sb, S and K/Al compose a suite of elements which are significantly dispersed away from, and increase toward mineralization. Ba, Ca, Na, Mn, V and Zr decrease toward mineralization. The suite is more selective than gold with respect to known mineralization within the exploration area.

Jan 1, 1992

By Cesar Carrasco, Heath Arvidson, Mark Forster

Block models built to represent the geology and rock characteristics of mineral deposits represent huge complex data sets, which form the basis of strategic and business planning, and public reporting of Mineral Resources and Mineral Reserves. Recent advances in cloud computing and database technology developed for the Internet of Things offer a different way of working with these critical data sets. Enabling a cloud based, open data structure with high performance data analytics capability presents a compelling improvement in governance and a democratization of ore body knowledge that can lead to automation use cases that support the digitalization of mining.

Jun 25, 2023

By L. G. Austin

The model originally proposed by Austin, et al., has been modified in the light of further investigation of the breakage laws in SAG milling. The model uses a fully-mixed reactor for short L/D mills and calculates the breakage of small particles by the nipping action of balls and pebbles. The autogenous self-breakage of larger lumps is treated as an effective means of fast breaking rock and much slower breaking rock. Experiments show that fast autogenous breakage can be treated as a first-order breakage with an overall specific breakage rate which incorporates fracture and chipping. Similarly, slow breakage incorporates fracture and abrasion. Autogenous breakage is cushioned by the accumulation of fine material. Simulation results are compared to results from tests in a 2 m diameter continuous pilot-scale SAG mill. Future work is discussed.

Jan 1, 1985

By C. C. Clark, D. J. Benton, J. B. Seymour, L. A. Martin

"The U.S. National Institute for Occupational Safety and Health (NIOSH) is conducting research on jackleg use and related accidents in underground metal mines. This paper provides an analysis and overview of jackleg drill usage, accidents, operational characteristics and alternatives, based on information from injury reports, legacy research, stakeholder input and published literature. The results indicate that jackleg drills are involved in more groundfall accidents in underground metal mines than any other drill, and jackleg-drill-related injuries are most prevalent at the face in the course of installing initial ground support. Practical mechanized alternatives to jackleg drills for drilling and bolting under incomplete support in narrow underground openings have not yet been realized. Small, versatile mechanized bolting equipment needs to be developed to address jackleg-drill-related accidents and improve safety at mines where jackleg drills are being used. IntroductionJackleg drill is a generic name for a handheld, rotary, percussion rock drill equipped with an attached reaction leg to provide stability and thrust (Fig. 1). All of the drill and leg controls are located near the operator’s handle at the rear of the head portion of the drill. Jackleg drills are classified according to the bore size of their pneumatic pistons, which normally range from 6.03 to 8.26 cm (2.375 to 3.25 in.) (Kurt, 1982; Clark, 2012). Jackleg drills typically weigh 46.7 kg (103 lb), but the weight can approach 54.4 kg (120 lb) after being fitted for operation with drill steel and air and water hoses (McKibbin and Clark, 2001). In underground mines, jackleg drills are commonly used to drill 3.8-cm (1.5-in.) diameter holes up to 1.83 m (6 ft) deep in rock."

Aug 1, 2016

By D. E. Healy

In 1989, an autogenous grinding task force was formed to study potential autogenous grinding circuits to replace the existing semi-autogenous grinding (SAG) at the National Steel Pellet Plant in Keewatin, MN. Pilot plant test work, performed by the Hanna Research Center (HRC), indicated that fully autogenous grinding with pebble extraction and crushing could be incorporated into the existing circuits. In 1990, one of the existing 10 grinding mills was converted for an in-plant test incorporating pebble crushing. Full-scale test work were conducted in 1990 and 1991. They verified the pilot plant projections with primary mill throughputs from the fully autogenous circuit using pebble crushing being greater than throughput of the existing SAG mill circuits. The plant produces 5 Mt/a (4.9 million ltpy) of iron ore pellets from 17.6 Mt (17.3 million It) of crude taconite. Crude ore is single-stage crushed by gyratory crushers. Primary grinding is performed by 10 semi-autogenous wet grinding mills. Secondary grinding is performed by five ball mills. Induration is with an Allis Chalmers grate-kiln pelletizing system. The primary grinding circuit consists of 108.2-m-diam x 5.5-m long (27 ft-diam x 18-ft) SAG mills. The mills are charged with 127 mm-diam (5 in.diam) steel grinding balls at from 3% to 5% by volume. Ball consumption rate is about 0.55 kg/t (1.25 lbs/lt) of crude ore feed to the mill. Each SAG mill is powered by two 2.6 MW (3500 hp) motors drawing 5450 kW (7300 hp) at 76% of critical speed. The mills are grate discharge with 16 mm (0.6 in.) slotted grate openings when new. The mill discharge is sized on a trommel screen having 4.5 mm (0.2 in.) openings. The plus 4.5 mm (+0.2 in.) oversize material is returned to the discharge end of the mill by a reverse screw auger located in the center of the trommel. The -4.5 mm (-0.2 in.) trommel screen undersize is pumped to magnetic cobbers.

Jan 1, 1992

By Brian H. Kaye

Efficient design of grinding circuits for efficient production of ultrafine material requires rapid feedback of information concerning the fineness of material leaving the grinding device. Generating this information requires efficient sampling and adequate rapid characterization of the material leaving the grinding machinery. Recent developments-in electrooptic inspection of dry end wet material leaving a grinding device are critically reviewed. New methods for characterizing ultrafines are discussed. A rapid operating automated cybernetic (intelligent) permeability device for automatic control of grinding circuits using Blaine index and other fineness indices is described.

Jan 1, 1983

By Douglas G. Brookins

Clay mineralogic studies of ore versus barren rocks in the Grants mineral belt show that some combination of chlorite (rosette form), illite, mixed layer illite-montmorillonite, (- Mg-montmorillonite) are penecontemporaneous with uranium minerals in trend ore; these same clay minerals plus kaolinite are related to the roll type ore near the main redox front of the Grants mineral belt. Clay minerals from barren rocks are characterized by a greater abundance of Na-montmorillonite, kaolinite, and face-to-edge form chlorite. Chlorites from ore zones contain much more vanadium than do chlorites from barren rocks. Trend ore probably formed from southeasterly flowing waters following paleochannels in the Late Jurassic. These deposits are found almost entirely in reduced rocks, and organic carbon may have been an important reductant to remove U-V-Se-Mo from solution as carbonate from ore zones contains some organic carbon based on stable iso¬tope studies. Uplift, remobilization and reprecipitation of some of the trend ore resulted in the formation of redistributed ore, some of which possesses a roll type geometry. Mineralization for the roll type ore was apparently controlled by sulfide-sulfate equilibria at or near the main redox front in the Grants mineral belt. Trend and roll type ore possess different assemblages of clay minerals and different trace element abundances. Laramide faults cut both trend and some roll type ore. Stack ore is found in Laramide fault zones. Limited oxygen isotopic data from clay minerals in two mines at Ambrosia Lake in reduced rocks indicate probable preservation of ancient, formational waters and no evidence for infiltration by young meteoric waters. This information, plus the pre-Laramide faults, suggest, but do not unequivocally prove, that the main redox front has been relatively stable since its formation, probably some time in the Cretaceous. Younger encroachment of the redox front in post-Laramide is proposed by others, however, and the problem is unresolved. Uranium for the deposits was most likely carried in solution as an oxyion, probably as (UO2(CO3)2.2H2O)2- or (UO2(HPO4)2)2-, although organic transport cannot be entirely ruled out. Oxyions of vanadium, selenium, molybdenum and possibly arsenic and antimony, are interpreted from Eh-pH diagrams to have been segregated and transported with U6+ soluble species and precipitated when a chemically reducing environment was reached. The rare earth elements are also enriched in ore zones, but it is not clear if they were transported with the U-V-Se-Mo-(As)-(Sb) suite or derived from a more local source.

Jan 1, 1980

By Neil H. Bostick

This research, sponsored at Stanford Research Institute by the Grand Junction Operations Office of the U.S, Atomic Energy Commission, was an outgrowth of the concern that presently-known ore reserves may be inadequate to meet the projected demands of nuclear power reactors. The original program at SRI was to design a comprehensive geological information system and use it to store and analyze the very great quantity of data needed to estimate uranium ore reserves. Study of the problem showed that it could be solved only by use of modern electronic data processing techniques, so such a comprehensive system was designed and tested. The system test was satisfactory, but input lead time and total expense were shown to be too great for the system to be practicable for the AEC under present circumstances. Thus, based on results of the earlier research, a specialized and simplified procedure for predicting approximate uranium ore reserves was devised. The prediction is based on general geology of specific area cells of the earth, in order to provide complete volume coverage; the strata in these ores are evaluated for uranium ore favorability on the basis of a few selected criteria in order to allow rapid data input. Since the bulk of U.S. reserves are in clastic host rocks only such strata are considered in this work. This paper describes the structure and some details of the resource system and how it was tested in rn area of the western United States.

Jan 1, 1969