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By T. J. Lynch

A new class of polymeric dispersants for industrial minerals has been synthesized and evaluated. Currently available dispersants give initial low viscosities at high mineral loadings, however slurry viscosities can rapidly double or triple on standing over the first several days. The new dispersants give low initial viscosities that are more stable and maintain a lower viscosity for at least one month. The new dispersants are made possible by controlling the polymer molecular weight distributions during their manufacture such that essentially all of the dispersant is adsorbed onto the mineral surface, preventing depletion flocculation.

Jan 1, 2012

By Charles A. Bankston, John C. Rowley, Robert J. Hanold, Joseph W. Neudecker

The basic concepts and processes of soil and rock melting as applied to excavation technology are reviewed. The electrically heated, small diameter prototype penetrator development sequence is presented. Emphasis is placed on the different methods of handling the fluid rock and soil melts and their significance in providing new solutions in hole support and debris handling problems. The refractory materials requirements, penetrator life and electrical heater technology are presented. Consolidating penetrators, which form stable glass-lined holes in low density rocks and soils, require no debris removal and will find applications in horizontal holes for utilities, cables, and pipeline installations. Extruding penetrators are being developed to make holes in dense, hard rocks. Melt is conditioned into a variety of debris forms, i.e., glass rods, pellets or rock wool, selected to match appropriate debris handling systems. Unique use in drilling into very hot rock or magma for geothermal exploration or production wells is projected. Some of the results of laboratory and field tests of these devices are compared with theoretically derived operating performance. Coring-consolidating penetrators for geological sampling in alluvium are projected to larger diameter self-propelled and guided coring devices for prospecting along proposed tunnel alignments. Application to the melting of annular shafts for pipeline support piles in difficult conditions such as permafrost has been scoped. Conceptual design studies of large diameter tunneling equipment have indicated the system contributions and economic aspects of rock melting relative to material comminution, wall and roof support and materials handling.

Jan 1, 1974

By M. Maier

Geographic Information Systems (GIS) has evolved into a powerful tool for analyzing spatial and attribute data in many industries including mining. Modern field data collection techniques add another dimension to the use of data in the field and enhance the utilization of GIS for mining applications. This discussion will review how field data is collected and how office data and maps can be taken into the field to be analyzed and verified using pen-based computers and differentially corrected GPS.

Jan 1, 2001

By John S. Carman

Our industry is in trouble. Real trouble. It has never been an easy, secure business. But to-day it is engulfed in revolutionary currents. No longer can there be reliance upon the checks and balances of market forces. Supply and demand largely dictated the economics of business enterprise in simpler days. To-day politics, in particular nationalism become increasingly dominant. And as governments expand and put out tentacles of interference in the direction of the mining industry, far too little understanding is evidenced as to how that industry works. Then there is something which is relatively new -stagflation. As the prices of minerals falls, the capital investment required for new extractive facilities soars at rates which far outdistance those which are cited by governments to indicate the magnitude of inflation. To illustrate; 1) In 1971 it was calculated that $355 million would be required to bring the Cuajone property in Peru into production. Five years later that stage was reached at a cost of $680 million. 2) With the Caridad mine in Mexico, estimated capital investment doubled between 1971 and 1976. 3) The requirements calculated for Cerro Colorado in Panama have risen in two years from $560 to $800. 4) The budget of $240 million for Sar Chesmeh in Iran in 1971 had become $500 million by 1976.

Jan 1, 1977

By Albert Hofstra, Joel Leventhal

The gray, dark gray and black colors of the sediments and the presence of pyrite in the Carlin, Jerritt Canyon, Horse Canyon, Betze, and Gold Acres sediment-hosted disseminated gold (SHDG) deposits indicate that these rocks are not oxidized with respect to carbon and iron sulfide. Both ore and non-ore host rocks generally are dark colored. Analyses for noncarbonate carbon (usually called organic carbon) in samples from SHDG deposits and related unmineralized rocks indicate that these rocks contain from a few tenths to a few percent carbon. We use the term noncarbonate carbon because, strictly speaking, organic carbon denotes carbon that is bound to hydrogen. However, the carbon present in SHDG deposits and related rocks has very little hydrogen chemically bound to it. Rocks with less than 2% organic carbon are usually gray in color. The dark colors in our samples are due to the relatively high temperatures that these rocks have experienced relative to organic matter maturation. We confirm the results of Nelson et al. (1982) that previous reports (for example, Radtke and Scheiner, 1970) were incorrect in reporting significant amounts of humic acids, extractable hydrocarbons (bitumen) or "carbonaceous" material. We believe these reports had problems with contamination or misdirected emphasis. Our samples consisted of unweathered rocks, collected mainly from mine cuts (benches, trenches, cores) and put into glass containers or wrapped in aluminum foil to avoid contamination. Only a few samples were collected from natural outcrops. We were careful to avoid samples in proximity to blast holes that were packed with ammonium nitrate and diesel fuel ("ANFO"). Contamination by ANFO may explain some of the previous reports of hydrocarbons, pyrobitumens, humic acids and anomalous nitrogen. When we were collecting samples, it was apparent that in addition to lithologic and color differences, the surface appearance of the rocks was distinguishable: "preg robbing" material that had a sooty surface; "graphitic" rock with a shiny surface; and more ordinary rocks that had a flat gray or black appearance. [Preg robbing is a term for ores that adsorb gold from the milling circuit; the graphitic material had not been x-rayed to actually identify graphite.] We hoped that laboratory study of these samples would show some fundamental differences that we could relate to ore genesis. Even though these sample types appeared different in the field, we could not distinguish any differences in thermal maturity (see below). Normal petroleum/organic geochemical laboratory procedures (solvent extraction, Rock-eval, pyrolysis-gas chromatography) failed to yield much information because the carbon was over-mature relative to oil and gas generation. Rock-eval results show less than 20 (± 20) mg of pyrolizable hydrocarbons per gram organic carbon (and an indeterminate Tmax) indicating that the organic matter in these deposits is burned-out relative to petroleum generation [with an H/C (atomic) ratio of less than 0.41. Because of the non-definitive results from standard organic geochemical methods, x-ray diffraction (XRD) and Raman spectroscopy were used to characterize the carbon. Prior to XRD, samples were treated with HCl and HF acids (1) to remove quartz that has a peak near 26° [20] at the position of the 002 peak of graphite and (2) to concentrate the carbon to a level detectable by XRD. The residue was put on a colodion mount and analyzed by XRD. The XRD analyses yielded a broad peak at 26° [20]. The shape of this peak indicates that the carbon is more thermally mature than anthracite rank coal but less mature than crystallized graphite. Based on XRD results from the literature (Landis, 1971) that are calibrated to metamorphic facies, results from our samples correspond to pumpellyite-actinolite to lowermost greenschist facies conditions, probably

Jan 1, 1990

The Functional Performance Equation for ball milling circuits allows us to isolate the circuit classification system efficiency (CSE) from the mill?s grinding performance. The factors which affect circuit CSE are reviewed, with emphasis on water usage at the classifiers. It is shown that manipulation of such water usage can be carried out to improve plant grinding circuit efficiency, at times by more than 30 percent.

Jan 1, 2009

By R. C. Burtan

Long before recorded history, man began to dig into the earth's crust in a never ending search for useful materials. It is well known that more than half of the earth's crust is composed of silicon dioxide (SiO2), also known as silica. Silica and silica-containing material have a great many uses in modern society. This material, however, is potentially an extreme health hazard. Silicosis: Not a New Disease Centuries before the Christian Era, Hippocrates wrote of a lung disease common to those who mined in hard rock. He was obviously describing silicosis. It is also apparent from ancient writings that the Egyptians were aware of this malady. Dioscorides also wrote on this subject in the fifth century B.C. It is undoubtedly the oldest and best studied of the occupational lung diseases. Silicosis was certainly described by Agricola in his De Re Metallica published in 1556. Here he described lung disease among hard-rock miners. The original document was written in Latin and then translated in 1912 by Hoover and Hoover. One of these translators was Herbert L. Hoover, a former US president who once made his living as a mining engineer. More recently, there are numerous references in medical literature in the 19th and 20th centuries relating silica exposure to silicosis. There are specific references to mining in hard rock, as well as to sandblasting and a host of other industrial exposures. In 1919, Winslow described standards for measuring the efficiency of exhaust systems in polishing shops using sandblasting. These standards were equally applicable in the mining industry. As early as 1920, Winslow explored the efficiency of certain devices used to protect sand-blasters against the dust hazard. These devices were equally applicable in the hard-rock mining industry. The medical community recognized the silica health hazard in the early 1900s. Middleton described the illness in the British Medical Journal in 1929. He noted the danger to health at that time. D. Hunter mentions in his book, The Diseases of Occupations (1969), the monumental work of Merryweather in 1936, in which he surveyed the silicosis risk in Great Britain. He showed statistically that the average employment length of sandblasters who ultimately died of silicosis was 10.3 years, compared to 40.1 years for all fatal cases, irrespective of occupation. Sandblasting and hard-rock mining and drilling, obviously, are very hazardous occupations. Weil and Zisking of Tulane University wrote in 1975 that "it was known as early as 1935 that the course of silicosis is much more rapid in sandblasters than in miners or foundry workers. This can be explained by the fact that sandblasters are exposed to an almost pure siliceous dust containing high concentrations of respirable particles within the range of 1 to 3 micron size." Protecting the Worker The medical community recognized in the early 1900s the need for proper protective equipment for all of those who worked with siliceous materials. Middleton, writing in 1929, said: "The worker is then protected by a close fitting helmet with an air feed, much as in the case of an underwater diver. In spite of these precautions, cases of silicosis among sandblasters are being met with today. It is a matter for serious consideration whether a substitute, such as steel or iron grit, could not be used to replace the siliceous grit as the abrading material." C. E. A. Winslow, a professor of public health at Yale School of Medicine, and others wrote of the need to protect sandblasters by

Jan 7, 1984

By A. M. Radigan, W. G. Prast

M.S. Azun The authors' paper did not explain the facts and reasons why state companies are established and what their role is in international industrial mineral trading. Also, I do not agree with the conclusion implying that the main goal for state companies is to capitilize natural resources. Almost all state companies are founded by certain laws and their activities are arranged by state regulations. Their only aim is to operate mineral deposits for their people and to protect the rights of the people. Although some ore deposits, such as nonstrategic or small, may be exploited by privately owned companies, the state has the right to control the operation and production. Activities of state companies may or may not be widened because of the character of the deposits and the importance of the mineral market involved. For some countries, although governments may occasionally change hands, the policy of the mineral trading system is not affected by this change. There is no doubt that any government desires to make more earnings to increase GNP, when it is involved in operating and trading mines. It wants to produce and sell the finished products, instead of unprocessed ones, if possible. When it is known that some mineral deposits are relatively rare, such as Turkish boron deposits, the government can nationalize the mines to control production and affect the market. If there is an abundance of a certain mineral in the market, the government can cut production and set a floor price, such as Canadian potash. Also, when production of a specific mineral is unique, such as Turkish chromite, the price of such mineral may be set by correspondant government. One may add that if some governments with their state companies produce a certain mineral in a larger amount, they may decide to establish a cartel to protect their production and price. These are the facts followed by government-owned state companies and partially government-owned companies. The reason being charge of many deposits by the state companies is always the same: "protect" the mineral rights of the people.

Jan 2, 1984

By Dale S. Hursh, William A. Brooks

Introduction US dependence on external energy sources is dangerous because of unstable political situations existing in key energy exporting countries. So, recent national energy policies call for increased reliance on domestic energy sources. Coal ranks as the most feasible domestic energy source due to its abundant reserves and continental distribution. But to efficiently extract these coal reserves, huge sums of capital funds are needed. Due to the depressed economy, lenders of capital funds are forced to be more stringent with loan applications. This results in fewer loans granted. In many cases, it is uncertain if funding can be obtained. Furthermore, the greatest level of domestic mine financing is expected to be in the coal sector. Demand for capital in the domestic coal industry is anticipated to increase 80% by 1990. The Chase Manhattan Bank in New York warns that these future needs cannot be met by the present capital markets. This article analyzes the current and expected situations of the capital markets available to the domestic coal industry, including: • current and expected future types of financing used in the domestic coal industry; • problems the domestic coal industry may encounter as it seeks capital; and • the future availability of capital funds as concluded from analysis of the first two items. Background Information Regardless of industry, all projects or ventures can be divided into four basic stages: generation; evaluation; selection; and execution. Within the mining industry, one can break down these stages to draw a clear picture of mine development, as shown in Fig. 1. Each successive stage has a corresponding risk level. This risk level defines the type of financing available to the mine operator. Mining Venture Risks A coal mining venture can be characterized by its unique blend of technical and financial risk. As the mine moves through different development stages, varying proportions of each of these risks are encountered. It is these risks that the lender evaluates to determine project suitability. For a coal mining venture, the major complexities generally occur with the technical risk. These include: • quantifying the coal reserves: • assessing the feasibility of the mining method; and • evaluating the design of the wash plant. The reserve risk is gauged by the amount of measured, mineable, and saleable reserves. The greater the latter amounts, the lower the risk. Secure title to the reserves plus title for any surface areas required are also of concern to the banker. Feasibility of the mining method and evaluation of the wash plant design should verify that the project can be completed according to the engineered spec-

Jan 9, 1982

A knowledge of airway friction factor (K-factor) is necessary to designing mine ventilation systems for least cost and optimum effectiveness. The friction factor used must be accurate and reliable to estimate correctly roadway resistances and pressure sources for required flows. Though the resistance to flow offered by mine airways has been an object of study over the last half century, no accurate relation has yet been established from which the prediction of the resistance of a projected airway can be made. In Kentucky, only limited and incomplete data on local K-factors are available. Therefore, there is a need for field investigations to determine these values in-situ for existing mining conditions. The author describes a study concerning K-factor that was carried out in ten coal mines, located in eastern and western Kentucky. The results of these investigations are presented in both tabular and graphical form.

Jan 1, 1991

By Chester M. F. Peters

INTRODUCTION There has been considerable discussion in recent years of the strained relations between owners, engineers and contractors caused by the rapid increase in costly litigation in underground excavation due to construction claims. These time consuming claims are not to the best interests of the industry. It has been a conclusion of some of the concerned parties that there could be a substantial reduction in these claims if a mutual respect for each other's roles could be maintained along with a practical contractual arrangement for sharing the risks of the unforeseen costs inherent in the business. This paper will touch on the overall problem of these relationships, but confine the major discussion to the role of geology in claims and, in particular, changed conditions claims, since they form the base for the bulk of those involving geology. Geologists can make a major contribution to the reduction of these claims if their particular abilities are recognized and used properly. CLAIMS AND GEOLOGICAL RISKS The tunnel contractor is strictly bound by the contract he signs, and the risks he assumes thereby must be priced. The most important variable factor on which he must base his price is the geologic data provided and his interpretation of it. If this data does not give a clear picture of the conditions, making it impossible to price

Jan 1, 1974

By A. K. Mukherjee

The roles of pulsating mechanisms such as the amplitude and frequency of the jig cycle are well established in jigging. Also well established are the roles of the size ratio and the volume fraction of the feed. In iron ore beneficiation plants, these process parameters are optimized to achieve the highest efficiency. However, the role of one of the more important feed characteristics, the liberation characteristic of the feed, has not been studied in detail. Evaluation of the liberation characteristics is difficult because the required washability test is not viable for iron ore feed. In this paper, a new method is proposed in which the liberation characteristics are measured through a separation efficiency value. In the new evaluation method, jigging parameters such as amplitude and frequency of the jig cycle are optimized from the fundamental understanding of the process dynamics and feed characteristics such as size distribution. Then, feeds with different liberation characteristics are tested to evaluate the liberation characteristics of feed in jigging.

Jan 1, 2008

By William M. Gleason

Hard times continued to plague the industry when the calendar rolled over to 2000. During 1999, the United States economy had grown vigorously, capping the longest economic expansion in United States history. However, the mining industry was not so fortunate. Commodity prices remained in a slump in the “new-economy” that was fueled by excitement and speculation about the power of the Internet during the infancy of the Information Age. Much of the investment money that once went to mining and exploration was now headed to the world of virtual gold mines. SME President Donald E. Ranta implemented new technology into his plans for SME. His two major goals were new membership growth and to foster the establishment of the comprehensive Internet presence for the Society’s technical information. His strategic priorities included enhancing the quality and quantity of publications, programs, meetings and short courses. “The Internet is the vehicle that will advance the priorities,” he said.

Jan 1, 2007

By M. J. Farrell

Mining is a significant emitter of greenhouse gases and is the focus of increasing attention from green groups and regulators. Miners need to know their own carbon emissions and how they compare with the rest of the industry. Miners and mining companies need to know where they fit in the emissions curve. Who is in the bottom quartile? This article updates data from minecost.com which detail the specific carbon dioxide emissions for over 200 mines producing 90% or more of western world copper, zinc, lead and nickel in 2009. This data shows the potential impact on mine economics of proposed carbon taxation regimes and emissions trading schemes proposed at COP 15 in Copenhagen during December.

Jan 1, 2010

By D. B. Sikka, R. B. Bhappu

Porphyry-type copper-molybdenum (Cu-Mo) deposits typically occur in the Phanerozoic rocks and have been well-documented. During the past two decades, a number of porphyry-type Cu-Mo deposits that range in age from 1055 Ma to 2970 Ma have been identified in the Precambrian rocks of Australia, Canada, China, Finland, India. Namibia and Zambia. The Malanjkhand porphyry copper deposit M.P., India is estimated to contain 789 Mt (870 million st) averaging 0.83% copper (mill headgrade); 0.004% molybdenum; 0.2 g/t (0.006 oz/st) gold; 6 g/t (0.175 oz/st) silver and a cap of 7.5 Mt (8.2 million st) of oxide ore averaging 0.8% copper. The economic potential of the expanded copper mining milling, smelting and refining complex is expected to yield cathode copper 118.6 kt (130,700 st); molybdic oxide 830 t (914 st); gold 1.9 t (61,732 oz); silver 46.6 t (1.5 million oz); sulfuric acid 240 kt (264,500 st), copper from leach dumps 11.5 kt (12,600 st); nickel 24 t (26,400 st); cobalt 84 t (92,600 st); bismuth 16 t (17.6 st); selenium 48 t (53 st), tellurium 4.8 t (5.3 st).

Jan 1, 1995

By John E. Shively, Tracy K. Lundin, Francis Fong

The Superconducting Super Collider (SSC) features two 20 TeV counter rotating proton beams which will be housed in 87 km (54 miles) of tunnel. Four additional lower energy particle accelerators will be housed in 26 km (16 miles) of tunnel and underground structures. Physics experiments will be conducted in two underground detector halls approximately 67 m (220 feet) deep with footprints measuring about 30 m (100 feet) by 100 m (330 feet). Definition and design of underground facilities is advanced with construction of approximately one-third of the SSC program underway. This paper presents an overview and status of the SSC project.

Jan 1, 1993

By Carlton M. Ray, William P. Levy, Thomas Lindberg

"The District of Columbia Water and Sewer Authority (DC Water) is implementing its $2.6 billion DC Clean Rivers Project to reduce combined sewer overflows to the District’s receiving waterbodies and mitigate chronic sewer flooding in District neighborhoods. The First Street Tunnel project is a major component of the DC Clean Rivers Project, designed to mitigate sewer flooding and basement backups in the District’s historic and densely populated Bloomingdale neighborhood. Bloomingdale has been historically affected by sewer flooding and was severely impacted by four storms in the summer of 2012 that caused significant damage to homes, the environment and public property. As a result, DC Water accelerated the design and construction of the First Street Tunnel in order to mitigate the effect storms have on the undersized sewers serving the neighborhood. The infrastructure designed to mitigate flooding, including the tunnel, are located within the highly urbanized neighborhood – with some structures being less than ten feet from residents front door steps. The success of a large public works project of this magnitude and in this unique location depends on a well informed and supportive public. With the local community impacted by flooding but concerned about heavy construction impacts, this paper details the components of a successful public outreach plan and lessons learned throughout the design and construction process. Early identification of community mitigation, working cooperatively with stakeholders and frequent dissemination of accurate information required the project team to establish a culture of problem solving collaboration with the community. BACKGROUND Chronic Flooding in the Northeast Boundary Sewershed The Northeast Boundary sewershed, in which the Bloomingdale neighborhood is located, is served primarily by a combined sewer system and has a long history of chronic flooding problems during moderate to severe storm events. The sewer system that serves the Northeast Boundary drainage area was constructed by the Federal Government in the late 1800's when developed areas of the District terminated at what is now Florida Avenue. Since construction of the system, population within the sewershed area has grown at an exponential rate. In meeting the growing needs of the population, the District experienced development that transformed previously low-density rural areas into new communities. Impervious areas have increased drastically since the sewer system was constructed and consequently, the existing sewer system does not have the capacity to convey storms with return frequencies beyond the 2-year storm without flooding. As a result of the capacity limitations, many of the low-lying areas have become chronic flooding areas due to the surcharging of sewers."

Jan 1, 2016

By D. Jepsen

Land access and tenure certainty for exploration and mine development is absolutely critical to the foundation of a healthy, sustainable and environmentally-sound mineral exploration and mining sector. Without certainty, mineral exploration will be severely eroded, resulting in reduced possibility of discovering and developing new mines. The development of positive relationships based on a shared commitment of understanding, mutual respect and trust by First Nations and the mineral sector can provide this increased business certainty and social and economic benefits for local First Nations. As a sector, we face many challenges in regard to building relationships with First Nations. The root solution to addressing these challenges lies in recognizing and understanding the unique cultural differences that exist between indigenous people and the business community. From the Canadian perspective, the First Nations culture differs vastly from non-Aboriginal culture. It is equally as imperative that cultural differences be acknowledged and respected at home as they are when seeking business opportunities in other countries. The traditional “business” approaches and relationships that one understands and incorporates with one’s contractors, legal counsel, investors and Board are generally not be the best approach for the introductory and subsequent meetings with indigenous peoples. This paper is written from the perspective of my experiences accumulated over the past ten years, first as Manager of Aboriginal Affairs for one of the largest forest companies in British Columbia and now, as President and CEO of the Association for Mineral Exploration BC (AME BC). My opinions are not necessarily endorsed by AME BC. Before the gritty issues of consultation and benefit sharing are dealt with, it is worthwhile to clear up the confusion surrounding terminology. “Indigenous Peoples” is used in a global context; “Aboriginal Peoples” is used in the Canadian context therefore includes Métis, Inuit and First Nations Peoples. The term “First Nations”, in the context of British Columbia, perhaps has its roots in the fact that treaties have largely not been settled. Therefore it is important to reaffirm that British Columbia was not discovered. First Nations have resided in British Columbia since time immemorial.

Jan 1, 2007

By James W. Marold

Tunnel and shaft plugs have been designed to assist in construction of new and rehabilitation of existing tunnels and shafts. Tunnel plugs have been used to provide construction access for side by side tunnels, separation of raw and treated water, and to allow operation of one tunnel during construction of a nearby tunnel. Shaft plugs have been used to seal up surface openings to tunnels and to prevent seepage of water to the surface through adjacent tunnels or shafts. The design construction details of tunnel and shaft plugs are provided. Typical examples of tunnel and shaft plugs are provided.

Jan 1, 2008

By Richard Weinstein, Richard Snoby

There are many advantages to upgrading coal with dry jigging technology. The most obvious is the lack of process water, which eliminates the need for fines dewatering and slurry confinement. Dry jigging eliminates the clean coal moisture penalty associated with wet processing. Particulate emissions are virtually nonexistent due to inclusions of fabric dust collectors on all modern dry jig plants. Because of the environmentally friendly nature of dry jig plants, installation permits are often measured in days, not months. There has also been a fundamental advance in dry jigging efficiency. All of these advantages have renewed the coal industry’s interest in dry jigging. But air jigging is not right for every application. There are limitations due to particle size, particle shape, moisture and near gravity content. This article explores the evolution of dry jigging. It reviews parameters important for determining the suitability of dry jigging. It also compares historical performance data as measured by imperfection, against results from modern dry jigging technology. The article also presents data from modern dry jig installations.

Jan 1, 2007