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By W. L. Hollinshead

For more effective and cost saving production in tunnels, the machinery used on construction sites will be equipped with guidance systems combined with working procedure management systems. This paper describes sensors for these systems and various system configurations. A project is described which uses a computerized guidance system on an underground mining machine for guidance and profile control.

Jan 1, 1999

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 U. K. Custred

In 1973, the United States production of marketable phosphate rock set a record in excess of 42 million tons. This production rate is expected to continue to increase, due to the growing international requirement for fertilizer, at a rate exceeding 5% per year well into 1977. This trend contrasts sharply with the reduced phosphate rock production levels of the 1966 - 1971 period. The natural consequence of this growing phosphate rock market is an evaluation of the variety of means whereby plant capacity can be most effectively increased. One approach toward increased plant production capacity is through large capacity flotation cells provided they can be successfully applied to the recovery of the relatively coarse product which is characteristic of the phosphate rock feed. This paper will summarize the results of a nine month evaluation test program, conducted at the Haynesworth Mine at Bradley, Florida in which the flotation circuit "specific capacity" (tons feed/ft.2 floor space) and "specific input power" (Hp/ton feed) were determined, and the feasibility of achieving economically acceptable concentrate grade and recovery levels was demonstrated, using large, high capacity, flotation cells.

Jan 1, 1974

By J. F. Fitzpatrick

This paper examines the cost elements associated with changes to gold mining practice over the last decade that result from the changes in environmental regulation and the heightened governmental and public awareness of environmental issues. The main experience base is Pegasus Gold Corporation's flagship mine, Zortman/Landusky, located in the Little Rocky Mountains of Phillips County, Montana. This operation was among the first mines that were permitted under the 1974 Montana Metal Mining Reclamation Act. In 1974, the Montana Metal Mine Reclamation Act was enacted, creating a permit system for metal and industrial mineral mines for the state of Montana. The act established the content of mine permit applications and defined parameters for the reclamation of mining disturbances. The Act can be viewed as implementing legislation for Article 9, Section 2, of Montana's Constitution, which provides that "all lands disturbed by the taking of natural resources shall be reclaimed." Pegasus Gold Corporation's Zortman/Landusky mine was among the first mines permitted under the new Act. In 1978, the initial permit applications were submitted for Zortman and Landusky, and a full Environmental Impact Statement was prepared by the Montana Department of State Lands; permits were issued in 1979. When opened later that year, the anticipated mine life for the combined Landusky and Zortman operations was approximately 18 years, based upon a proven and probable ore reserve of 43.2 million tons. Zortman/Landusky was the first large-scale heap leach gold mine in the United States. Its distinguishing feature was, and remains, a remarkably low ore grade, now .016 oz/ton. The ore is economic because it requires neither crushing nor agglomerating to leach effectively. Approximately two years after the initiation of the state's regulatory process, the Federal Land Policy Management Act (FLPMA) was enacted, establishing a mine regulatory framework for lands under the administration of the Bureau of Land Management.

Jan 1, 1992

By N. J. Themelis

Autogenous grinding, broadly defined as the self-comminution of ore in a cylindrical tumbling mill without using auxiliary grinding media, was first applied in the early thirties in the so-called Hadsel mills (Figure 1) mainly used in gold mines on the U.S. West Coast. A number of these mills were built in sizes of 20 to 24 ft. in diameter and five-six feet in length but were later abandoned because of operating and maintenance problems. Further development of autogenous grinding led to the Hardinge wet grinding mill (Figure 2), the Aerofall dry grinding mill and others. A tabulation of all known autogenous and semi-autogenous installations around the world was sent recently to the authors by Hr. G. J. Kushner of the Koppers Mineral Processing Division. In the size range of 24 to 32-ft. in diameter, it lists a total of thirty mills used in the processing of copper ores. An additional 120 units are listed in the same size range for the processing of iron ores and other minerals. The largest mills in existence are 36-ft. dia X 15-ft. long mills in Minnesota, powered by 12,000 hp. motors and used in taconite beneficiation. It is indicative of the phenomenal growth of this technology that none of the above one hundred and fifty mills was in operation prior to 1964.

Jan 1, 1978

By R. J. Grace

Carbon in the form of coke is used as a reactant in various chemical and metallurgical processes, The high cost of by-product coke along with its periodic lack of availability and high investment necessary for additional by-product recovery facilities indicate the need for a low-cost production unit based on a new procedure for coke manufacture, Traveling-grate coking-stokers were developed by Shawinigan Chemicals Ltd. to produce coke required for carbide manufacture, They were adapted to kilns so that the hot volatile gases could be used for lime burning, Their operation has been described in various patent disclosures (1, 2, 3), and their application to rotary lime burning kilns has been described by Andersen (4). Details of the process and plants have also been published by Kurt Baum (5,6).

Jan 1, 1958

By Pawan Bharadwaj, Wim Mulder, Thomas Tscharner, Guy Drijkoningen, Rob Jenneskens

"The Earth’s properties, composition and structure ahead of a tunnel boring machine (TBM) should be mapped for hazard assessment during excavation. We study the use of seismic-exploration techniques for this purpose. We focus on a seismic system for soft soils, where shear waves are better and easier to interpret than compressional waves, as has been shown over the last decade. The system is intended to be deployed on the machine’s cutter head, with a few seismic sources and sufficiently many seismic sensors to tackle spatial variability and noise characteristics. An important property of the newly developed system is its ability to process data with very little human interaction. Images need to be available in near real time, without human interactions slowing down the imaging process. This can be achieved by employing Full Waveform Inversion, which minimizes the difference between modeled and observed data. Because this method may suffer from local minima in the cost function if the data lack low-frequency information, we employ a dedicated seismic source that can generate sufficiently low frequencies for the relevant length scales. With data acquired in a number of field settings that mimic realistic TBM configurations, we show that the designed seismic system can successfully look ahead of the TBM and offers a valuable capability to support decision-making during tunnel excavation. INTRODUCTION While excavating a tunnel with a Tunnel Boring Machine (TBM), the geology and the ground conditions along the planned tunnel trajectory need to be investigated in order to safely and efficiently carry out the underground operations. This entails detecting the occurrence of boulders, foundations, pipes and faults, necessary to prevent hazards and time-consuming delays in the tunnel boring operations. In order to facilitate ground prediction ahead of a TBM, techniques as used in seismic exploration can be deployed. Two components common to seismic-exploration techniques are data acquisition and processing, the latter including inversion. We will discuss each of these for the application to tunnel excavation with TBM, in particular for soft soils."

Jan 1, 2016

By T. H. Parker

The Guasare Coal Project is located a short distance from Lake Maracaibo, in the Northwestern region of Venezuela. In 1987, Carbones del Guasare, a joint venture comprised of Carbozulia, ACC Venezuela, a subsidiary of ARCO, and AGIPCoal of ENI Group, Italy, was formed to develop the Guasare coal reserves for world markets. Drilling with the Venezuelan state of Zulia has indicated a coal resource of over 6 billion metric tons. Further exploration has delineated the Guasare deposit as an area particularly suited for cost-effective surface mining. The calculated mineable reserves of this area (300 million metric tons) and the coal quality characteristics are based on extensive core drilling programs.

Jan 1, 1989

By William Gleason

"Speakers and attendees of the 2016 Cutting Edge Conference could not be faulted for keeping one eye on the presentations taking place at the Hyatt Regency at LAX in Los Angeles, CA on Nov. 7 and 8 and another on the results of the historic election in the United States that took place on Nov 8. While there was certainly interest in the presidential campaign, there was also a great deal of interest in Measure M on the California ballot. Measure M, which passed easily, is a half-cent sales tax increase that will fund the most ambitious transit expansion in Los Angeles County history.In the coming years, the ballot measure will transform a traffic-choked region by funding the construction of nearly a dozen new rail lines with an estimated $120 billion raised in four decades. Among the projects that could come to fruition are a twin-rail tunnels project through the Sepulveda Pass and new connections in the city.During the update on West Coast projects, Bill Hansmire summed things up with a slide asking “How much work is there on the West Coast,” and his answer was “Billions.”From Seattle, WA south to Los Angeles, there is already a lot of work for tunneling and underground construction experts, and Measure M ensures that there will be plenty of work for decades to come.Currently, The Los Angeles County Metropolitan Transportation Authority (Metro) has three rail projects underway that were funded by Measure R in 2008 — the Regional Connector, the Purple Line subway extension and the Crenshaw/LAX Line that are designed to alleviate the traffic pressure with an eye to more solutions.Measure M is the fourth sales tax increase to fund transportation in L.A. County, bringing the base sales tax rate to 9.25 percent. In some cities, which already levy their own sales tax, the rate would be higher, The Los Angeles Times reported.About 35 percent of the revenue will fund major new transit projects, such as the subway under the Sepulveda Pass, extension of the Gold Line to Claremont, extension of the Crenshaw Line to West Hollywood and acceleration of the Purple Line Subway construction along Wilshire Boulevard to finish in 2024, 10 years earlier than scheduled.About 17 percent would fund a dozen highway improvement projects, such as widening parts of I-5 in the Antelope Valley and southeastern county, adding bus lanes to the Sepulveda Pass section of the 405 freeway and adding truck-only lanes to a section of the 710 freeway."

Dec 1, 2016

By D. F. Strong

Most Newfoundland. mineral deposits can be clearly classified as within rocks formed either as accreting plate margins (ophiolitic pyrite-chalcopyrite massive sulfides such as Betts Cove, Whalesback, York Harbour, chromite at Lewis Hills, and asbestos at Baie Verte), at consuming plate margins (Kuroko-type polymetallic massive sulfides such as Buchans and Pilleys Island, porphyry-type Mo-Cu at Rencontre, fluorite at St. Lawrence), or within plates (zinc deposits at Daniels Harbour, sedimentary iron ores at Wabana, manganese in Conception Bay.) As these metallogenic patterns can be convincingly extrapolated southward into the Appalachians and northward to the Caledonides, they provide an important means of eliminating and selecting areas for particular exploration targets. Sonic criteria are described for the recognition of these environments of differing economic potential.

Jan 1, 1973

By D. Williamson

In the post war years metals analysts and statisticians have generally tracked the demand for metals in line with changes in OECD industrial production (IP) growth rates because, undoubtedly, the correlation between IP growth and metal demand was reasonable. However the correlation was exaggerated. During times of expanding IP growth metal demand increased at a faster proportional rate than IP growth. This was probably due to industry restocking in anticipation of growing demand at the start of each economic cycle. Conversely, metal demand would slacken at a greater rate than would be suggested by negative IP growth as industry destocked in order to reduce costs. Nonetheless, overall, a reasonable correlation between IP growth, over the longer term, and metal demand could be painted. Yet, although this correlation has stood well since the last world war it has been based on the fact that the bulk of the world's IP growth stemmed from the industrialized countries of the western world, latterly including Japan. The so called "developing world" was of little consequence, whilst countries of the Soviet Union and Communist Bloc were deemed to be closed, self-contained entities which, for each metal, would either be net exporters or importers. These quantities would be used by analysts to calculate the overall supply/demand equation for the western world only and to deduce whether a commodity was in shortage or surplus. It is now believed that this method of projecting total world supply and demand for raw materials is outdated and takes little account of the worldwide political changes which have occurred since the collapse of communism and the revitalization of China, albeit under a notional communist government. It is no longer appropriate to assess global balances for raw materials on the basis of three economic blocs namely, western world, developing world and communist bloc. Rather, global balances need to be projected on a global basis. In this regard, since the collapse of communism and the removal of many other totalitarian regimes, capitalist forces are at work and are attempting to satisfy, with some considerable success, the expectations of the great mass of the world's poorer people. Such people, usually located in Asia, Africa and Latin America have aspired to the same standard of living as people living in western Europe, North America and Japan. Now, with free market forces at work their aspirations will start to be met. Consequently, the demand for metals and other raw materials will now rise at a much faster rate than at any other time in the world's history. Not only will the production of raw materials have to keep pace with rising IP in the developed world but will also have to keep pace with the demands associated with the rising expectations of rapidly increasing populations in the developing world, as well as from within the old communist bloc countries. This paper sets out to argue the case that metal demand could well increase at a rate faster than the world's mining companies, governments and financiers can deliver.

Jan 1, 1997

When a company like Lonmin, the third largest platinum producer in the world, is mining one of the most precious metals in the world, time is money. Every piece of equipment is expected to be in top shape because every minute of downtime can add up to lost profit. Two different types of platinum ore are mined and processed by Lonmin, namely Merensky and UG2. Merensky has a grade of 3.5 g/t (0.1 oz/st) and UG2 has a grade of 4.5 g/t (0.13 oz/st). The mine also produces platinum group metals (PGM), which consist of platinum, osmium, palladium, rhodium, iridium and ruthenium. Although South Africa has more than 80 percent of the world?s PGM reserves, these minerals are very scarce. Lonmin is considered a low-cost producer of these minerals, generating 21.5 t (694,000 oz) of platinum and 18.6 t (600,000 oz) of PGMs in 2012. So when the company?s Karee K3 concentrator plant in Rustenburg, North West Province, South Africa, was experiencing high operating costs on the transfer points, a solution was needed.

Jan 1, 2012

By J. Philip Bromberg

Any effectuation of a viable program of air pollution control will' require a basic understanding of the chemistry of atmospheric processes, the fate and migration of SO2, and the ultimate health effects of the sulfur oxides themselves. The migration and ultimate fate of Sop discharged into the atmosphere will be discussed with particular emphasis on the various conflicting views and how these relate to our present emission control regulations. Our present lack of knowledge is a severe detriment, and consideration will be given to those particular areas where future research may best be directed to provide the answers to a number of perplexing questions.

Jan 1, 1976

By Julian W. Feiss

Before undertaking to present to you a current analysis of copper, I would like to preface my remarks with a few observations that in themselves have a bearing upon commodity reviews in general. Having sat through a large number of such reviews since first joining the A. I. M. E. nearly forty years ago, I have no illusions about the hazards of the undertaking. If a speaker presents a statistical summary of commodity economics for the last year, most of his audience, having already read at least four commodity summaries on the identical subject, either get up and walk out or fall asleep. Should the latter happen, and were the listener to tumble from his chair and break his neck, obviously the speaker is liable. The subject matter seldom lends itself to histrionics on the part of the speaker so dangers of heart attack in the audience are not too great. Therefore the speaker, in order to retain listener interest, resorts to prophecy. Such venture was undertaken long ago by weather soothsayers, the "harouspex" of Ancient Rome, who generally cut up a sacrificial sheep and after staring at the entrails made their predictions which I understand had a batting average somewhat better than those undertaken on Wall Street based upon Dow Jones averages. Not being a licensed harouspex I cannot undertake predictions. I shall, however, fall back upon the experts.

Jan 1, 1965

By John E. Dreier

The Pachuca-Real Del Monte district, Hidalgo, Mexico (Figure 1) has produced roughly 1,500,000,000 oz Ag., 6,000,000 oz Au. and minor Pb., Zn, and Cu from about 100,000,000 tons of ore since discovery early in the 16th century. Production has come from epithermal vein deposits that have been up to 8 km in length, 650 m in vertical extent and 45 m in width but which averaged 200-400 m in length and vertical extent and 2-4 m in width. Ore deposits occur through-out an area about 12 km E-W by 10 km N-S (Figure 2) and between the elevations of 2000 and 2800 m above sea level. The deposits occur as shoots in the veins and terminate laterally where the veins narrow, upward where the veins pinch out and downward where the veins decrease in silver con-tent to below the cut-off grade; the veins are known to extend 500 m below the bottoms of the ore bodies and probably extend to much greater depths. The district lies wholly within a mid-to-late Tertiary volcanic rock sequence that is made up principally of andesite and dacite lava flows and flow-breccias. Although the bottom of the sequence is not exposed in the district, stratigraphic constructions indicate the volcanic rocks to have an aggregate thickness of 2000 to 2500 m. Structurally, the area is characterized by gentil warping and normal faulting of the volcanic rocks. Pre-ore modifications to the volcanic rock sequence consisted mainly of faulting along west-trending, south-dipping normal faults and north-trending high-angle faults.

Jan 1, 1978

By Colin Irwin, Adrian Naranjo-Castillo, Christopher Petta, Eric Zarobila

The Shoreline Consolidation Sewer is a CSO control project in Cleveland, Ohio that requires the installation of 5,000 feet of 72-inch inside diameter pipe using microtunneling methods. After award, the contractor submitted a value engineering proposal to eliminate two deep shafts and install the tunnel in two drives instead of four. In an example of successful collaboration, owner, contractor, and engineer worked together during the initial construction stages to modify the design and update the contract documents. This paper examines the importance of exible requirements in contract documents and a collaborative environment between all parties to successfully deliver a project.

Jun 23, 2024

By C. L. Emery

The geology and early history of the discovery of potash in Saskatchewan as described by Heber Cole (1) and R. V. Thompkins (2) has dealt with the distribution of the salt beds and their potash content. From the many bore holes through the Prairie Evaporites the outlines and contours of the series have been well established. The thickest section of the salt beds lies to the north of the "barren" area and forms a belt running easterly to a point west of Yorkton. The "barren" area is a region where the salt has been redissolved and the strata have slumped down, to fill the voids. This area is of interest from the standpoint of rock mechanics. The potash-rich beds extend both east and west of the region. mentioned and the top of the Prairie Evaporite is at a depth below 3200 feet from the surface near Saskatoon and dips southerly at an average rate of about five feet to ten feet per mile.

Jan 1, 1966

In late November 2010, a Laotian landmark was achieved for the country?s first tunnel boring machine - (TBM) driven tunnel. Italian contractor CMC di Ravenna celebrated the breakthrough of a 7.6-m- (25.1-ft-) diameter Robbins single shield TBM for a hydroelectric tunnel on the Nam Theun River. The Theun Hinboun expansion project and 5.5 km (3.4 miles) headrace tunnel will bring much needed power in-creases to Laos and Thailand. . ?Since this is the country?s first machine, it has awakened people?s curiosity and interest. We had experienced Italian and Chinese crew members, but we also trained many Lao workers during the course of the project, as this was something they had not seen before,? said Luca Barbàra, Far East Manager for CMC di Ravenna. The machine broke through on Nov. 21 into an exit shaft close to the intake structure on the river. The machine is now being disassembled and removed - CMC hopes to use it on upcoming projects in the region. Due to the current rainy season and relative low level of the tunnel, the last 100 m (330 ft) up to the intake structure will be completed using drill-and-blast after the waters recede below the tunnel invert.

Jan 1, 2011

By Mike Ghassemi

It is clear that precise overground and under-ground mapping is an important factor for all designers. Due to rapid changes in underground construction, tunnel designers are increasingly in need of updating project information. This article explains the latest techniques for detecting under-ground utilities as well as underground mapping. Global Positioning System (GPS) is a very ac-curate and popular navigation and mapping system that has been used extensively above ground, but is not used for underground mapping as signals are not strong enough to pass through ground or water. Most underground techniques were developed for military applications during the first and second world wars. Later, the techniques became public. For example, ground penetrating radar was developed for the military in 1970 to be used for locating tunnels under the demilitarized zone between North and South Korea. Later, the same technique was used for detecting unexploded ordinance such as plastic land mines.

Jan 1, 2011

By Arif Emre Dursun

The aim of this study is to present hazard classifications of location, type and causes of accidents in the Turkish coal-extracting industry using the analytic hierarchy process (AHP). In this study, fatal mine accidents were analyzed by pairwise comparison and weighting, and the most important hazards were identified by determining the effective main and sub-criteria among location, type and causes of accidents. For this purpose, first-, second- and third-level hazards consisting of location, type and causes of accident were determined by using the data of fatal mine accidents in underground and openpit coal mining in Turkey between 2010 and 2020.

May 1, 2024