Search Documents

By K. Kohli

A case study involving a historic structure undermined by longwall mining is presented in this paper. The location of this study is in South Western-Pennsylvania; USA. The structure is 150-years old and subsided 4.5 feet. This paper discusses the mitigation measures taken to reduce the subsidence damage and its effectiveness.

Jan 1, 2002

By P. Massacci, F. La Marca, G. Bonifazi

Certain deposits of incoherent materials which are near the surface and exploitable by open-pit mining may be characterized in real time before they are mined through an analysis of ground-surface imagery. If the slice to be stripped is not overly thick, in fact, surface texture and color properties may be extrapolated to its entire thickness. Image analysis techniques to process ground surface images acquired in situ(or in the laboratory shortly after their acquisition) which yield pattern vectors representative of RGB color component distributions and HSB texture parameters have been developed. The techniques were applied to a mineral sandy ore deposit containing three different lithotypes. Geostatistical analyses showed that the data used to characterize the lithotypes were reliable. The correct recognition of the lithotypes was carried out using a multi-barycenter classification algorithm. Such in situ image-analysis procedures open the way to the proper selection of the ore to be mined, or the proper way for run of mine (r.o.m).processing, or the appropriate blend to be processed before or at the same time as the mining process itself is enacted.

Jan 1, 1999

By Thomas Schwind, Pamela S. Moran

For short tunnels, a reinforced cast-in-place lining is not economical and shotcreteis a logical substitution. In the past, reinforced shotcrete linings have been constructed with lattice girders and welded wire fabric. For the Russia Wharf Tunnel in Boston, MA, the Contractor, with the help of the Dr. G. Sauer Corporation offered the MBTA a VECP to substitute the reinforced cast-in-place concrete lining with a steel fiber reinforced shotcrete lining. The challenge was to adequately model the ductility of the steel fiber reinforced shotcrete and to test the shotcrete prior to and during construction to assure quality control. To our knowledge, this type of numerical simulation has not been used on any other tunnels in the US.

Jan 1, 2005

"What is your assessment of the minerals business?My experience with mining has been primarily in the coal sector until about 10 years ago, when I also became heavily involved in the aggregates and industrial minerals sectors. I have also had peripheral involvement through family and partners in the gold sector, with just enough exposure to gold to become fascinated. In 1994, I visited Ghana and considered the possibility of taking an expat assignment at a surface gold mine that had just been started.It is not news that the coal sector in this country has suffered tremendously in recent years. Especially hard hit is the central Appalachian region, where a number of factors combined have had a devastating effect on production, jobs and the economy. These factors include federal regulations affecting coal production and use, higher production costs and decreasing market share of Appalachian coal by the switch from lower sulfur coal in favor of lowercost, higher sulfur coal from the Illinois Basin, as utilities have installed scrubbers to comply with Phase II of the 1990 Clean Air Act Amendments. Nationally, the lower cost of natural gas has been a huge factor affecting coal use. In Kentucky, for example, which exports to other states around 70 percent of its coal, those markets are disappearing, as utilities close coal units in favor of natural gas. This is a structural change in the electricity market, and one that will become more pronounced as federal greenhouse gas regulations are implemented.We often hear the phrase, "the war on coal." While there are certainly a number of market factors affecting coal production and use, this phrase captures a different element that is all too real. The attacks have come from environmental activist groups for many years; from some in the media and, in the last few years, from a White House administration that believes strongly in alternatives to coal. Then, there really is an alternative to coal in the form of the previously untapped unconventional gas reserves that allowed utilities to move away from coal.Coal mining will continue in this country. In fact, it appears that our production is holding fairly steady at about a billion tons a year. And predictions that I have seen indicate this will continue for the next few years. What impact the Environmental Protection Agency’s Clean Power Plan will have beyond 2020 is another question.What do you feel is the future of the minerals industry - near term and longer term?Our society depends on the future of minerals in this country being strong. Near term, we are going through some of the typical cycles. Having also been involved in aggregates during the last few years, the business follows government infrastructure projects, such as highway construction and public and private sector development. Those sectors are heavily dependent upon government spending and a strong economy. Increased spending in those sectors, which appears to be on the horizon, should provide additional market shares for aggregates."

Jan 1, 2014

By N. Iverson, E. Haft, V. T. McLemore, M. Woodard, E. Owen

Present and emerging technologies are renewing interest in domestic rare earth elements (REE) production. REE deposits throughout the North American Cordilleran alkaline-igneous belt are being re-examined for their economic potential. In New Mexico, the mineral deposits found in this belt are associated with Eocene–Oligocene alkaline to calc-alkaline igneous rocks. Four areas in New Mexico have been examined for their REE potential. The chondrite-normalized REE patterns are similar for all four districts, even though different REE minerals are found. Crandallite, xenotime, bastnäsite and brookite are found in fluorite veins and carbonatites at Laughlin Peak. Bastnäsite was extracted during fluorite processing from 1954-1980 from the Gallinas Mountains, where samples as high as 8% total REE are found in fluorite veins. Other REE minerals include agardite, parasite, xenotime, and monazite. Allanite, thorite and as much as 8133 ppm total REE are found in fluorite veins in the Capitan Mountains. In the Cornudas Mountains, exploration along the outer edge of the Wind Mountain nepheline syenite laccolith and within phonolite dikes, plugs, skarns and carbonate-replacement deposits in Chess Draw contain as much as 3110 ppm TREE, hosted in eudialyte, monazite, bastnäsite, and calciocatapleiite.

Feb 1, 2023

By W. James Marold

The New Croton Aqueduct (NCA) was the first major water supply tunnel for New York City. The 50-km (31-mi) long tunnel has 33 open shafts 6 m (20 ft) to 121 m (397 ft) deep. The tunnel and shafts are lined with brick and mortar, with cast iron lining and pressure covers in six pressurized shafts. Details of the 1895 construction are provided and compared to modern construction techniques. The paper provides rehabilitation techniques for the shafts and pressure covers, including grouting, epoxy lining, temporary bulkhead design and installation and placement of tremie concrete 98 m (320ft) below the water level in a 122 m (400ft)deep shaft using a Remote Operated Vehicle (ROV) to monitor the placement.

Jan 1, 2008

By James Westfield

I welcome this opportunity to appear before you and to review briefly the various health and safety services of the Bureau of Mines available to the mining industry, other than coal, and also to tell of our plans for extending these services to improve safety and health conditions. The Bureau's health and safety activities are basically services by which we attempt to develop and disseminate information on improved techniques in mine accident prevention and promote mine safety education in the mineral industries. Unfortunately, some mining companies, particularly some of the smaller operations, seem to be unfamiliar with these services, The Bureau of Mines is charged by law with the responsibility for inspecting coal mines; other services to the coal mining industry and are provided only on request, Safety inspections and other services that we offer are provided for noncoal mining industries solely upon request.

Jan 1, 1958

By C. R. Stephan

Explosion-resistant seals in underground coal mines isolate the environment within the sealed area from the active workings of the mine. The current United States Title 30 Code of Federal Regulations (CFR) requires these seals to be constructed of solid concrete blocks. The CFR also allows for alternative methods or materials to be used to create a seal if they can withstand a static horizontal pressure of 138 kpa (20 psi), provided the method of installation and the material used is approved in the ventilation plan. The purpose of this report is to identify those explosion- resistant seals that have been tested and meet or exceed all the requirements of the CFR.

Feb 24, 1997

By Feng Liu

"With seven new applications for plans of work for exploration in the international Seabed Area approved by the Council during its twentieth session of the International Seabed Authority, 26 total approvals have been made by the Council up to date. Among them, three contracts were made with COMRA. On 8 August 2014, China Minmetals Corporation submitted another application to the Authority for approval of a plan of work for exploration for polymetallic nodules in the Area, which is also sponsored by the Government of the People’s Republic of China.China is one of the main contributors to the international seabed regime. The Presentation will describe China’s activities in the Area, such as exploration, technology development, environmental protection and policy making.JIAOLONG is a submersible with capacity of 7000 meters. JIAOLONG’s sea trials were carefully made in 4 years, from 2009 through 2012 and it successfully dove to a depth of 7062m in June 2012 at Mariana trench. A so called "Test Application Phase" started thereafter, and is planned to last for 3-4 years. Two cruises and 4 legs have already been made since then. A wide-range of findings were obtained during dives in South China Sea, and in COMRA’s Exploration Contract Areas for polymetallic nodules and cobalt-rich ferromanganese crusts. This presentation will reveal the colorful findings."

Sep 1, 2014

By T. P. Meloy

Traditionally the mineral and mining engineers have characterized particles by sieving and-settling. Within the last decade, with the advent of the scanning microscope, entirely new experimental and theoretical approachesl-10/have been taken to minutely define the particle surface. This approach depends upon a hypothesis which takes advantage of the recent developments in automatic micro-scopes which can acquire large amounts of information in a short time and the new computational techniques which rapidly reduce the information to meaningful, practical data. Historically sieving and settling are the oldest sizing techniques known. Sieving by square screens, shown on Figure l-A is a common, current practice for sizing particles both in the laboratory and in production. A woven cloth is used which usually has square openings. The size particle that will pass through the opening dependent on a complex relationship of its morphology. As can be seen in Figure l-A, neither the width nor the height of the particle is determined by sieving. From square screens one and only one parameter characterizing the particle size is obtained, that parameter is the radius of the sphere that will just pass through the given sieve opening. A variation of square mesh screen is the slot screens, shown in Figure 1-B. Here another measure more closely associated with the height of the particle is obtained. Once again, one and only one parameter is associated with the particles' shape.

Jan 1, 1977

By Marcelo de Oliveira, Antoine Allanore, Dennis P. Chen, Davide Ciceri

Potassium fertilizers (potash) are mined in a handful of countries in the Northern Hemisphere. Potash is either expensive or unavailable to the farmers of the Southern Hemisphere. Alkaline alteration of K-feldspar rock (ultrapotassic syenite) in autoclave in the presence of Ca2+ generates a mixture of K-bearing calcium-aluminum-silicate-hydrate (C-A-S-H) minerals that potentially can be used as an alternative local fertilizer. This work investigates the effect of processing temperature (200 °C, 220 °C, and 230 °C) and time (from 0.5 to 3.0 h) on pH, mineralogy, and elemental availability of the C-A-S-H mineral mixture. Increasing temperature results in an increased conversion of K-feldspar and increased content of both the mineral tobermorite (Ca5Si6O16(OH)2·4H2O) and amorphous phase in the resulting C-A-S-H mixture; increasing time results in an increased conversion of α-dicalcium silicate hydrate into tobermorite. The amount of K leached from the mixture is relatively constant across all processing conditions. Hydrothermal alteration in autoclave of K-feldspar-bearing rocks such as ultrapotassic syenite permits the synthesis of a potential potassium fertilizer which alkalinity and mineralogy can be tailored according to soil requirements.

May 22, 2020

By Paul Richardson

This paper will review several projects completed during the period from 1976 through 1984 which have been carried out utilizing big hole drilling concepts. The projects discussed will be from various industries to demonstrate the extent that big hole drilling methods are being used along with the current state of development. There will be a discussion of projects planned for the future where big hole drilling methods are the only technology being considered. Also included in the discussions will be an overview of the most recently completed heavy oil recovery project. During the next decade, big hole drilling methods will be used more and more in all industries where underground access is required. The safety, speed and economics associated with shaft sinking using drilling methods are becoming more and more recognized and the technology is rapidly becoming an accepted shaft sinking method.

Jan 1, 1985

By George Joseph Malina

Contractor chose and Owner allowed concrete to be placed using the arch first principle while excavating the 35'-3" O.D. rock tunnel. The contract included excavating and lining 26,000 L.F. of rock tunnel to 33'-I.D. Concrete was placed at a rate of 90LF per working day using a movable bridge to allow batching, mixing and pumping of concrete adjacent to the tunnel form.

Jan 1, 1981

By M. I. Al-Wakeel

Nile sediment was collected as a waste from one of the water treatment plants in Cairo, and subjected to petrographical investigation and granulometric, chemical, and mineralogical analyses. It was expected to find diatomite in that sediment but it was a surprise to find that the diatomite content amounted to about 52.01% by volume in addition to quartz, orthoclase and clay minerals. The latter are represented by montmorillonite and illite minerals. The sediment is light gray in color, soft and has low density and high surface area, such density and surface area generally decrease with temperature. The sediment absorbs 317% of its weight in water. The diatomite skeletons are the main factor responsible for its high porosity producing microporosity and low density, and these particles are concentrated in the very fine silt size fraction (11x2µm). The common diatoms in such sediment include Cyclotella ocellata Pant, and Melosira granulata (Ehr.) Ralfs. It seems that this Nile diatomaceous sediment has many advantages over the fossil diatomite, such as Fayium diatomite in Egypt, with the absence of carbonate minerals that require grinding and calcination those cause destruction of the cellular structure and energy consumption. This Nile diatomaceous sediment can be processed using sequential classification to obtain diatomite concentrate of 88.8% grade at 90.6% recovery, and a middling product of 19.4% grade and 5.8% recovery. The suggested flow sheet is quite simple to produce diatomite product for different industries at a low cost. The unusual particulate structure and chemical inertness make diatomite an ideal mineral to be used as functional filler in a wide range of industries, and as catalyst carriers and insulating material. Key words: Egypt, Nile sediment, Diatomite, Beneficiation, Sedimentation, Classification.

Jan 1, 2008

By Nord L. Gale

Lead, zinc, copper, silver, cadmium and many other heavy metals which are potentially hazardous if released into the environment in wastewater discharges have been of considerable concern to governmental agencies, industry and the general public. In response to this concern, an interdisciplinary research team at the University of Missouri has been funded by the National Science Foundation-RANN program to study trace contaminants associated with the production of lead for the past eight years. Seven modern mines in close proximity to two lead smelters in the forested Ozarks of Southeast Missouri are the largest source of lead in the world and in 1976 alone produced 504,095 short tons of lead, 82% of the United States total production. This new and rapid industrial development in a sparsely populated. rural forest region has offered a unique opportunity for studying the impact of trace metals and for developing improved techniques to control detrimental effects. Research on the wastewater discharges and two methods of biological and recycle control are discussed in this paper. Although the two mine-mill complexes investigated in this study have many similarities, the differences between the two are substantive and warrant separate examination.

Jan 1, 1977

By M. D. Flavel

Research programs conducted by Allis-Chalmers Corporation are showing that the most efficient energy use in crushers is achieved when the forces applied to particles undergoing breakage are increased. Laboratory bench scale tests have been developed to confirm this phenomena, which was first observed in the field using HYDROCOME crushers with automatic setting controls. A new testing machine is described and methods of maximizing such benefits are postulated. FOREWORD Allis-Chalmers Corporation was founded in Milwaukee, Wisconsin, in 1847 as the E. P. Allis Company, which had an initial interest in manufacturing components in the grinding of flour. As such, its roots were started in reducing material size, which is covered by the generic term, comminution.

Jan 1, 1981

By S. N. Gurulaxmi, Veerendra Singh

The abstract discusses the increasing consumption of manganese ores and the need to utilize low-grade ores and rejects. The study focuses on developing a low-cost process using a cupola furnace to recover manganese values from these resources. The process involves smelting ore blends to produce high MnO slag and pig iron. The study investigates various factors to improve iron reduction and separation from MnO-bearing slag. The results show that the process can produce slag with MnO > 35% and Fe(t) < 5% using low-grade Mn ores. The process also achieves Fe reduction between 50 and 70%. The cupola furnace offers advantages like low cost and ease of operation, making it suitable for processing low-grade ores and rejects to produce synthetic MnO-enriched products for various industries.

Apr 1, 2022

By D. R. Wilburn

This summary of international mineral exploration activities for the year 2010 draws upon available information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analyses of exploration activities performed by the mineral industry. Three sources of information are reported and analyzed in this annual review of international exploration for the year 2010: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia; 2) regional and site-specific exploration activities that took place in 2010, as compiled by the USGS, and 3) regional events including economic, social and political conditions that affected exploration activities. These were derived from published sources and unpublished discussions with USGS and industry specialists.

Jan 1, 2011

By H. Sevim

In this paper, the research effort in simulating the operation of underground coarse-coal hydrotransport systems (UCCHS) is summarized. The equipment of the system to be simulated is already optimally selected by using an analytical optimization model. The purpose of the simulation model is to test the performance of the system and to obtain the distribution of the operating parameters such as water and power consumption, amount of slurry delivered to the preparation plant, etc. Knowledge of the distribution of these parameters is essential for the efficiency of the design and the operation of the system.

Jan 1, 1985

By Steve Kral

It seems that mining has been in the doldrums for awhile. Except for gold, metals prices remain depressed. And economic conditions in the United States and around the globe have put governments in a financial bind. This affects new building and infra-structure repairs, which, in turn, have a major impact the building materials industry. Add to that the severe environmental and regulatory restrictions placed on the mining industry in developing new mines and expanding existing ones. It’s enough to make a mining engineer/geologist/metallurgist go sell real estate. So why do those employed in the mining industry stay in the business and remain optimistic? Many of them will say that they have been through down cycles before and know that an upswing is in the offing. They also know that society will always need the commodities they produce. And they love the challenge. The challenge in mining’s case is producing commodities as cheaply as possible, in an environmentally sound manner and improving the quality of life in the communities where they work.

Jan 1, 2003