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By Bee R. Waples

The Alimak Raise Method, using the Alimak Climber, has proven to be a new, fast, economical method of driving raises at the Iron King Branch of Shat-tuck Denn Mining Corporation, Humboldt, Arizona. In order to fully understand the advantages of the Alimak Raise Climber, it is necessary first to describe the basic machine; second, a complete cycle of a raise round; and third, the comparative speed and economy afforded the Iron King operation by using this new method of raise driving: The raise climber consists of a drilling platform that is raised and lowered by two 6.2 HP compressed air motors that drive, through roller chains and sprockets, three worm gears connected in series. These worm gears drive pinions which grip the guide rail rack. The worm gems are fitted with spring-loaded couplings so that a small rock or grit in the rack is passed over without disturbing the mesh between the rack and the other pinions.

Jan 1, 1961

By E. D. Stephenson

As part of the British Steel Corporation?s development plan during the 1970?s, it was decided to concentrate its bulk steelmaking processes based on the BOS at 4 major Works with access to deepwater ore terminals, for the supply of high-grade imported ores. These 4 sites were at: - 1. Rarenscraig Works in Scotland where the ore terminal would be hilt at Hunterston on the west coast some 50 miles away. Bavenscraig was already an integrated Works but suffered from having to discharge ore 27 Glasgow tenxinus on the River Clyde, which could only accommodate vessels up to 25,000 tonnes. In the future, ore was to be unloaded at Runterston and shipped by a rail-link into Ravenscraig, The new ore terminal would have the potential to unload vessels up to 300,000 tonnes. - 2. Port Talbot Works in south Vales where the existing harbour was developed to discharge large ore carriers. This again was an existing Integrated Works and the benefits of the new harbour also applied to Llanwern Works which was another integrated Works some 50 dies to the east, which would now receive ore from Port Talbot.

Jan 1, 1980

By Elnaz Saminfar, Jae Bateman, Eric Westergren, Mark Trim

This paper presents a case study of two major Australian infrastructure projects that used digital engineering to facilitate design delivery: WestConnex Project (Rozelle Interchange), and Sydney Metro West (Eastern Tunnelling Package). The paper presents project overviews and building information modeling (BIM) execution and focuses on modeling techniques, software utilization, data management strategies and how the digital models helped the design-build team mitigate impacts to schedule by identifying clashes between disciplines before the execution of work. Finally, it demonstrates the positive and transformative impact of digital engineering on the design and construction of large underground infrastructure projects and highlights its role in asset management throughout the project lifecycle.

Jun 23, 2024

By S. Partney

Waste clay ponds are a necessary part of the phosphate rock beneficiation process. They are large, averaging a square mile in size; unsightly, in that they protrude 20 to 50 feet (6 -15 meters) above natural grade; stabilization and reclamation is slow; and they have had a history of catastrophic failure. The State of Florida has never published a specific rule regarding the configuration or height of these ponds, but has enforced numerous policies along these lines. The current rules are given and interpreted, along with the reasoning for current policy. In addition, an overview of the history of the policies, and an attempt at explaining the reasons for the changes that have occurred is given. The industry has been forced to make major monetary decisions, having effect for decades on mine economics, in a constantly changing regulatory environment. The Bureau of Mine Reclamation is confident that a direction of regulation has been solidified, but changes are still to be anticipated.

Jan 1, 1998

By Rongjie Kong, Shiwei Wang, Guomin Wei

Owing to the selective oxidation and uneven combustion that occur on the surface of carbon anode, some carbon particles detach and form carbon residue, which is defined as spent anode slag (SAS). The highly graphitized and toxic impurities such as fluorite ( CaF2), corundum (α-Al2O3), and cryolite ( NaAl11O17) are crucial components of SAS resource but are difficult to separate from graphite. This study developed a method of using water-soluble (emulsified) kerosene to separate the carbon particles from the toxic impurities in the SAS resource. The flotation purification approach of utilizing conventional kerosene was experimentally investigated and compared with that of using water-soluble kerosene. The results showed that with the use of emulsified kerosene, the maximum combustible matter recovery of the carbon particles was 89.86% while that of using traditional kerosene was 80.30%. The emulsified kerosene was comprehensively examined by various instruments to clarify its adsorption mechanism on the carbon particle surfaces. Because of the superior dispersibility of emulsified kerosene, it effectively envelops carbon particles with a smooth surface, oxygen-containing functional groups, and hydrophilic C–F bonds, thereby increasing the surface hydrophobicity and flotation responses of targeted carbon particles.

Feb 6, 2024

By Fabrizio Fara

The Ship Canal Water Quality Project (SCWQP) includes a 2.7-mile long, 18'-10" internal diameter tunnel which is located inWest Seattle. Tunneling in urban areas and soft ground conditions (Till and Till-like soils in Seattle) is associated with the risk of settlements, especially in presence of groundwater above the alignment. The Designer foresaw the use of soil improvement (jet grouting) outside of the launch shaft to mitigate the risk of flowing ground and to provide a redundant sealing. The Contractor proposed and ultimately successfully executed a different approach by using a “Steel Bell System” or Pressurized Can as described in this paper.

Jun 13, 2023

By J. A. Marts, R. C. Gilmore, Jr. Bogin, S. A. Saki, J. F. Brune, J. W. Grubb

The main purpose of mine ventilation design is to provide sufficient quantity and quality of air to the workers and to dilute methane and other contaminants. It is generally perceived that the additional air along the longwall face will improve methane dilution on the face and in the tailgate. However, computational fluid dynamics (CFD) modeling efforts at the Colorado School of Mines (CSM) under a National Institute for Occupational Safety and Health (NIOSH) funded research project have found that higher flow velocities along the longwall face are shown to increase the pressure differential between the gob and longwall face allowing more methane to be entrained in the active face and tailgate (TG) area, thereby negating the dilution effect. The increased face ventilation causes an increase in pressure along the headgate side which allows more oxygen to ingress into the gob area, thereby increasing the amount of oxygen available to form explosive methane air mixtures in the gob and to support spontaneous combustion of the coal. Two things are happening at two different locations along the longwall face, increase in pressure as the flow enters the active area cause an increase in pressure which forces more oxygen into the gob, but as the flow is developed along the longwall face, the higher velocities causes greater pressure drop allowing methane to enter the active face further downstream from the headgate (HG) towards the tailgate side. In this paper, a parametric study will be presented to discuss the effect that varying the face air quantity has on methane concentrations in the tailgate and formation of explosive gas zones (EGZs) in the gob. Counter to conventional wisdom, it appears that increased longwall face air quantities may increase the explosion hazard as they result in increased EGZ volumes in the gob, along with increased methane quantities in the tailgate return.

Jan 1, 2015

By A. Vien

A major thrust in Industrial automation over the past few years has been the exploration and incorporation of higher level (supervisory and optimizing) control strategies aimed at more fully exploiting the existing control system infrastructure. There is little doubt that this is worthwhile pursuit, however, one must not lose sight of the maintenance and development requirements of the basic control system. Statistics on loop performance indicate that this too is an area of considerable potential. In this paper the authors look at some of the less elegant, but arguably equally important issues in mineral processing plant control. The focus is on controller structures, loop tuning, sampling, filtering, and some of the other principal components of the regulatory control foundations. In many cases significant improvements In control performance can be achieved by getting back to the basics.

Jan 1, 1998

By Mahesh C. Jha

Cyanidation has established itself as the main process for extracting gold from ores in this century. However, many ores exhibit refractoriness to the conventional cyanidation process. The main cause of the refractoriness is generally the presence of carbon, tellurium, and sulfides, particularly those of antimony, arsenic, and iron. The problem is usually solved by either modifying the cyanidation conditions or providing an oxidation pretreatment. This paper presents results from studies that help in understanding the causes of refractoriness of various gold ores. This is followed by a discussion of many processes that have been developed to solve the problem such as intensive cyanidation, pressure cyanidation, carbon-in-leach cyanidation, and pretreatment processes such as roasting, chemical oxidation, autoclave oxidation, and bacterial oxidation.

Jan 1, 1986

By Enrique Jelvez, Pierre Nancel-Penard

The traditional way of generating open-pit mine production schedules has several limitations. This work addresses the design and production-scheduling problem by considering minimum operational space requirements under a Direct Block Scheduling approach to generate extraction sequences that satisfy the operational space required. For this, traditional formulations were extended by including a new set of constraints that generate operating spaces for mining equipment to move and extract material. Then, a heuristic algorithm produces close to optimal practical pushbacks. This proposal was applied in a case study, and the results show its ability to generate practical production schedules without sacrificing expected return, obtaining differences in terms of Net Present Value (NPV) lower than 1% when compared to the traditional approach.

Jun 25, 2023

By Rameshwar Sah, Bharath Kumar Shanmugam, Govinda Raj Mandela, Marutiram Kaza, Harsha Vardhan, Harish Hanumanthappa

Iron ores obtained from different sources differ in their chemical and physical properties. These variations make the process of grinding a difficult task. The work carried out in this context focuses on three different samples of iron ore, viz., high silica high alumina, low silica high alumina, and low silica low alumina. The grinding process for all the three iron ores is carried out individually in Bond’s ball mill and the total retention time taken by each iron ore sample is calculated. The present investigation focuses on utilizing the calculated retention time of the iron ore as a standard grinding reference time to the laboratory ball mill for optimizing the grinding time of each ore. The desired P80 (150 μm) with an acceptable range of hematite liberation (> 75%) was obtained in the laboratory ball mill after reducing 6 min from the total retention time taken in the Bond ball mill.

By J. R. Koehler

Mining practices at the Sunnyside Mines, Sunnyside Coal Company, Sunnyside, UT, have been documented by U.S. Bureau of Mines researchers to preserve the extensive history of yield pillar-based longwall gateroad system evolution on the property. An overview of the historical mining conditions, practices, and innovations that resulted in the evolution of the two-entry yield pillar gateroad system currently employed at Sunnyside was developed from interviews of 30 long-time Sunnyside employees. Employing yielding chain pillars at Sunnyside virtually eliminates tailgate pillar bumps and contributes to reducing face bumps. Limiting the overall width of the gateroad system benefits bump control and especially, roof and floor stability.

Jan 1, 1994

By A. E. Isaacson

Bureau of Mines researchers developed and tested equipment to measure corrosion rates on a commercial-scale mill. Bench-scale experiments were designed for duplicating ore grinding conditions closely enough that realistic rate determinations can be made in laboratory tests. Rates measured in a laboratory system compared favorably with those measured in the field. Cast steel was found to have corrosion rates in a copper mill and laboratory test cell of 22 and 21 mpy, respectively. Corrosion was found to account for less than 5 pct of the total grinding media wear in the operations studied.

Jan 1, 1987

By Robert E. Barry

For new coal-fired power plants, federal regulations require that emissions of sulfur dioxide be limited to 1.2 pounds for every million BTU'S burned. This is equivalent to coal with a sulfur content of roughly 0.7 percent for Eastern bituminous coals and roughly 0.6 percent for Western sub-bituminous coals. The states and their political subdivisions are free to apply more stringent standards and to develop implementation plans covering existing and new units. Most Western-sub-bituminous coals contain less than 1% sulfur and hence their use, in many cases, will allow a utility to meet the regulations. However, there are problems in using such coals in furnaces designed for Eastern bituminous coals, and furthermore it will take many years to open mines and provide transportation facilities to utilities which are now burning coals with a higher sulfur content. Moreover, pending federal legislation would outlaw strip mining on land to which the federal government owns the mining rights. Those utilities who, for one reason or another, intend to continue burning Eastern bituminous coals with sulfur contents in excess of 1 percent are faced with removing SO2 from the stack gases. The alternative of utilizing coal gasification where the sulfur is removed prior to burning in a power plant is still in the early stages of development. Therefore, a large number of processes are under development for SO2 control.

Jan 1, 1974

By F. Kitzinger

The possibility of increasing the efficiency of mineral processing plants by means of computer control has prompted metallurgists to examine their flowsheets more critically in order to develop practical control strategies. Control schemes in use to date generally rely on the automation of traditional and previously manually regulated control loops, for instance the addition of reagents to maintain a constant assay or a constant pH. This approach is predicated on the availability of well-established primary sensors such as pH electrodes or on-stream analyzers. Noranda Research Centre, in cooperation with Noranda Group concentrators, has developed a froth level monitor and a pulp density meter susceptible of application in this type of control. Although some of the basic principles on which they are based have been known for some time, their incorporation into the design of reliable, direct-reading instruments which can be interfaced with a computer, is be-lieved to be novel*.

Jan 1, 1977

By A. Robison, V. T. McLemore

"The San Juan Basin, New Mexico contains many heavy mineral beach-placer sandstone deposits of Cretaceous age. Beach-placer sandstone deposits are concentrations of heavy minerals that formed by mechanical concentrations (i.e. settling) of heavy minerals on beaches or in longshore bars in a marginal-marine environment. They have high concentrations of several elements, such as Ti, Zr, rare earth elements (REE), Sc, Y, U, Th, Nb, Ta and Fe. These elements are becoming increasingly more important to industry, because they are used in the manufacture of devices our society uses every day, i.e. cell phones, computers, and alternative energy devices, like solar panels. It is unlikely that any of the beach-placer sandstone deposits in the San Juan Basin will be mined in the near future because of small tonnage, low grades, high iron content, and distance to processing plants and markets. However, as the demand for some of these elements increases because of increased demand and short supplies, the dollar value per ton of ore rises, enhancing deposit economics. Current studies at the New Mexico Bureau of Geology and Mineral Resources are focused on the Apache Mesa (formerly Stinking Lake) deposit near Dulce, New Mexico. INTRODUCTION Beach-placer sandstone deposits are accumulations of heavy, resistant minerals (i.e. high specific gravity) that form on upper regions of beaches or in long-shore bars in a marginal-marine environment. They form by mechanical concentration (i.e. settling) of heavy minerals by the action of waves, currents, and winds (Fig. 1; Bryan et al., 2007). Modern examples are found along the Atlantic Coast, USA (Koch, 1986; Carpenter and Carpenter, 1991), southeastern Australia (Roy, 1999), and Andhra Pradesh, India (Rao et al., 2008), where they are mined for titanium, zircon, and monazite (a Ce-bearing rare earth, REE, mineral). Detrital heavy minerals comprise approximately 50-60% of these sandstones and typically consist of titanite, zircon, magnetite, ilmenite, monazite, apatite, rutile, xenotime, garnet, and allanite, among other minerals. Most of these minerals have a high specific gravity exceeding 4 and are dark colored, giving the sandstones a dark color, resulting in them being called black sandstones. Although beach-placer sandstone deposits are found in strata of all ages; the deposits in the San Juan Basin in New Mexico are restricted to Late Cretaceous rocks belonging to the Gallup, Dalton, Point Lookout, and Pictured Cliffs Sandstones (Fig. 2; Table 1; Chenoweth, 1957; Houston and Murphy, 1970, 1977). The beach-placer sandstones are black, dark gray, to olive-brown, resistant to erosion, and radioactive due to radioactive zircon, monazite, apatite, and thorium minerals. Anomalously high concentrations of Ti, Fe, Nb, Th, U, Zr, Sc, Y, and REE are characteristic of these deposits. Similar Upper Cretaceous heavy mineral, beach-placer sandstone deposits are found throughout Montana, Wyoming, Utah, Arizona, and Colorado (Dow and Batty, 1961; Houston and Murphy, 1970, 1977; Zech et al., 1994)."

Jan 1, 2016

By Greg Struble

The Homestake Gold Mine is one of the deepest and most extensively developed hardrock mines in North America. The mine is divided into five divisions which produce a total of 1.7 million metric tons of ore per year. In the past, labor intensive mining methods such as open cut-and-fill, shrinkage, and timber stoping were utilized. In recent years there has been an extensive change to the more productive methods including Vertical Crater Retreat and Mechanized Cut-and-Fill. Also, the percentage of production from the lower divisions below the 4850 level is increasing while upper level reserves are beginning to decline. Combined, these factors have strained the ventilation resources to the limit. By early 1984 it became clear that future production trends would require a detailed study of future ventilation resources. By November of 1984 the Ventilation Department completed a study to project these future requirements. This paper will detail the first phase of a scheduled two phase upgrade: the installation of a new surface fan.

Jan 1, 1987

By Mauricio Brücher, Juan Camus

This article deals with open pit mine planning and a computer technology known as Direct Block Scheduling, or “DBS”. This is an emerging technology for modeling mine exploitation strategies using mixed-integer linear programming. This technique has proved to yield stronger economic results compared to the Lerchs-Grossmann (“LG”) algorithm currently used at the beginning of the mine planning process. The article briefly describes the shortcomings of current practice; then, this delves into the superior results obtained by DBS technology compared to current practice. Finally, the article argues that results achieve so far by DBS could be enhanced even further. To do this, the framework to apply this emerging technology, which is also used in current practice, should be modified to better exploit the capabilities of DBS technology. To better understand this change, an illustrated case study is presented at the end of the article.

Jun 25, 2023

By R. H. Goodman

The development of techniques for separating minerals based on differences in their specific gravities is reviewed and their present applications in process technology outlined. Special emphasis is placed on the development, in Australia, of new models of the spiral concentrator. The mechanics of separation of spiral separators are stated, including the effects of operating parameters, Some of the traditional areas of spiral application are described, together with examples of new applications such as treatment of fine alluvials and tailings, separation of liberated minerals at coarse sizes and fine coal recovery.

Jan 1, 1984

By Muhammad Azeem Raza, Muhammad Zaka Emad, Muhammad Usman Tahir, Saqib Ahmad Saki, Muhammad Usman Khan

Shotcrete is a key initial rock support component used in underground mining and civil projects. The strength of shotcrete plays a vital role in providing and deciding the support adequacy. The strength of shotcrete is evaluated by its uniaxial compressive strength (UCS) test that is usually conducted on extracted core samples. Shotcrete cores are commonly extracted from the test panels along the direction of its application; thus, its strength perpendicular to the direction of application is often neglected. The true bearing strength of shotcrete is thereby ignored despite the fact that higher stresses act normal to the direction of its application. Although the anisotropic behavior of shotcrete is well reported, no study has reported extensive testing of this scale and nature. This study reports extensive testing of shotcrete cores extracted from tunnels of a mega hydroelectric project in Pakistan. The study reports 7- and 28-days strength tests of shotcrete cores. The research also investigates the anisotropic behavior of steel fiber reinforced shotcrete and suggests that shotcrete exhibits higher strength perpendicular to the direction of its application.

Dec 26, 2022