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By Nate Ober, Heath Rushing

"Mining companies want to be in a position to move quickly and seize a favorable market or to keep their key staff productively busy. One of the problems for these companies is the time required to compensate for unavoidable impacts that the mine will have on the natural environment and to gain environmental permits. All too often, circumstances that were favorable when the project was proposed have become less favorable by the time all the hurdles have been cleared.Accordingly, many mining companies are interested in ways they can inject more predictability into their timelines for gaining environmental permits, shorten those timelines, and be more certain of getting the permits they need to carry out their next project.One increasingly popular way to do this is through a relatively new kind of service — the mitigation bank.Mitigation banks purchase property or easements through property that has been impacted by agricultural, industrial or resource activity. They then turn it around from an environmental point of view. This might include restoring streams and wetlands so that fish and aquatic organisms can survive, and animals have habitat and food to flourish.Appropriate native species of plants including trees and shrubs are planted, and steps may be taken to introduce wildlife to the new habitat. In some cases, a special focus is placed on creating habitat for rare and endangered species of plants or animals.The property is inspected by regulatory authorities, coordinated through an interagency review team (IRT). If the property is determined to be effective as natural habitat, the mitigation bank is then issued credits that it can then sell to development projects that are creating an unavoidable permitted environmental impact elsewhere. A mining company, for example, would buy credits to offset the aquatic impacts due to construction of a mine, access roads and other infrastructure — as required by the Section 404 Clean Water Act permit that governs those unavoidable aquatic impacts. The mitigation bank used for offset must have an IRT-approved service area that includes the location of the impacts."

Jan 11, 2017

By John R. Bogert

The title of this session is "Wall Street Looks at the Mining Industry," and I am going to attempt to answer the question: Shouldn't Mining Stocks Sell at Higher Price Levels? Or, What Does Wall Street See When Looking at the Mining Industry? Well, it sees a capital intensive business, a technical industry, and a growing industry becoming more vertically integrated. But, at the same time, Wall Street sees a cyclical industry, a fragmented industry of erratic earnings, spotty public relations, a feast-or-famine business where the public usually does not differentiate between coal mining or metal mining, and does not appreciate either the risks or the rewards. As a result, mining stocks generally sell at relatively low price learnings ratios in comparison to other industrial groups. This PIE ratio, the current market price of the capital stock divided by annual earnings per share, is probably the most popular index of a stock's value. The average of the price/ earnings ratios of the 30 stocks comprising the Dow Jones Industrial Average is over 14. This diverse group of stocks is widely regarded as being a cross-section and representative of the industrial companies listed on the New York Stock Exchange. However, in comparison to 14, Asarco and Kennecott shares are currently available for about 8 times annual earnings. Even discounting earnings from South America, the stock of these two companies sells at only 10 times earnings. Of course, Peruvian politics is currently preventing Cerro shares from selling above 6 times earnings, and Chilean politics keeps Anaconda shares at a PIE multiple of 7. However, even in better times, these companies rarely sell above 10 times earnings. American Metal Climax and Newmont sell at only 11 times earnings as does Phelps Dodge and St. Joseph Lead. Few mining companies then have what can be considered a high PIE ratio-a figure higher than

Jan 1, 1970

By J. F. Cornelsen

Wheel loaders are currently being used in many mining applications for a variety of reasons. While they sometimes provide the lowest loading cost, a primary advantage of the wheel loader versus other loading systems is the increased versatility and mobility inherent in a wheeled vehicle. The advent of large wheel loaders with much greater digging capability enhanced wheel loader usage in severe loading applications. To match these severe conditions, machines offered today were designed to work in these rocky conditions. Soon after the introduction of large wheel loaders into rocky conditions, however, it became apparent to many users that tire costs could at times account for up to 50% of total hourly operating costs on large wheel loaders. In some applications, tire costs alone pushed wheel loader economics beyond the economic feasibility for these jobs, prohibiting their use. In an effort to combat high tire costs, several attempts have been made to put fast moving steel around the tires to provide a strong interface between vehicle and ground. Some earlier attempts involved wrapping tracks around tires. Mechanical difficulties with these systems limited their customer acceptance. Subsequently, the development of protective tire chains came into favor. While tire chains offered added protection to the tires, the cost and maintenance of the chains remains a problem in 1972, the Dystred arrangement was announced for usage on a 6 cu yd wheel loader from Caterpillar Tractor Co. (See Figure 1). The Dystred offered the advantages of greatly increased tread life over conventional tires, as well as resistance to tread puncture in most situations. The arrangement basically employed a track system similar to that used on track type loaders. Pin and bushing wear often caused high hourly operating costs and excessive machine downtime. In addition, the connection of shoes through the use of links, pins, and bushings forced a limitation on too speed of the vehicle.

Jan 1, 1976

By R. Q. Honaker

Dense medium processes are used to clean over 50% of the coal that is fed into preparation plant facilities worldwide. The dense medium is formed using ultrafine magnetite which is recovered after the cleaning step using drain-and-rinse screens and magnetic separators. Despite the high efficiency of the recovery system, magnetite losses of around 0.5 to 1.0 kg/ton are common. Considering the recent escalation of magnetite to around $300/ton, an alternative source of magnetic material from coal combustion bottom ash has been investigated. A relatively low cost recovery system has been developed. Dense-medium tests using the bottom ash magnetics revealed a high level of efficiency as indicated by probable error values around 0.03 over the range of medium densities investigated. The results from both the recovery and coal cleaning efforts will be discussed in detail.

Jan 1, 2009

By E. Lovera

Social attention to environmental aspects, steadily increasing in European Countries, has been leading to a stricter regulation of many productive activities. Among them, mining and quarrying sectors have been often censured for their potential and real impacts on land and environment. Referring to dimension stone exploitation (also the terms ornamental stone or natural stone are here used as synonymous), quarries are often concentrated in extractive basins, where the resource is localized with suitable quality and quantity: this fact has sometimes raised critical environmental situations. Nevertheless, dimension stone quarrying represents in Europe a traditional and important economical activity, source of wealth and employment. Moreover, many natural stones take on a ?cultural? value and may be considered as ?classic?, as they have been exploited since antiquity and are element of the architectural heritage of many Countries. The sector relevance demands the research of a sustainable balance between social-economical needs and environmental protection. Actually, very restrictive environmental protection policies have led to severe limitations to quarrying activity, but the results do not seem to be completely positive in terms of sustainability: on the one hand, closing-down stone quarrying activities imposes a shrinkage in local, social and economical development; on the other, quarrying activity is pushed towards developing Countries, environmentally un-protected, simply moving and putting off to next future the problem. The challenge of the sustainable development of quarrying sector ? recently explored in the European Commission?s communication ?Promoting sustainable development in the EU non energy extractive industry? (COM-2000-265) ? should be achieved through a positive link between theoretical statements and practical effects: sustainability indicators may be an effective instrument to assess and monitor the environmental performance of the industry. The paper refers to the development of specific ecological criteria and indicators, which can be useful to measure and predict the eco-efficiency of a dimension stone quarry, finally pointing out where improvement efforts have to be focused.

Jan 1, 2003

By John M. Ackerman

In the spring of 1988, Freeport-McMoRan Resource Partners Ltd. Partnership, IMC Fertilizer Inc. and Homestake Mining Co., as joint venturers, were awarded the sulphur lease for Main Pass Block 299, lease number OCS-G 91372. This was one of 11 leases awarded to the joint venturers. Following the initial discovery wells in December 1988, delineation drilling confirmed proven sulphur reserves of 68 Mt (67 million long tons). Proven, recoverable oil and gas reserves are 6.2 Mm3 (39.4 million bbl) and 1114 Mm3 (7.2 billion cu ft), respectively. Development of the sulphur mine was given approval as a fast-track project in 1989. The oil and gas reserves were acquired from the original hydrocarbon lessee in 1990 and were also given fast-track status. Fast-track for these projects meant design and engineering would not be complete before construction began. Joint venture The Main Pass Joint Venture is one of 13 joint ventures formed between Freeport and three other companies - IMC Fertilizer, Inc., Felmont Oil Corp., a wholly owned subsidiary of Homestake Mining Co., and Texasgulf Minerals and Metals Co. Felmont has since changed its name to Homestake Sulphur Co. Texasgulf assigned its interests to its parent company. Texasgulf did not participate in the Main Pass 299 joint venture. Joint venture negotiations, anticipating a lease sale in mid-1988, began in December of 1987. This joint venture, the first of its kind, was created to acquire offshore leases, explore, develop and mine sulphur. The Interior Department's Minerals Management Service (MMS) announced a lease sale date of Feb. 24, 1988 on the first business day of 1988. This greatly accelerated the joint venture negotiations. Of the 13 leases the joint ventures bid on, 11 were awarded. Freeport holds its interest in all the leases through its ownership interest in Freeport-McMoRan Resource Partners, Ltd. Partnership. Resource Partners is the operator on all of the leases.

Jan 1, 1992

By Jonathan M. Pachter

Introduction The Bailey mining complex is located in Greene County, PA, in the Talley Run valley. It includes two Pittsburgh No. 8 seam deep mines (Bailey and Bailey No. 2), a coal preparation plant, and two refuse areas. Clean coal is shipped from the complex by way of a 24-km (15-mile) rail spur. It con¬nects to the Monongahela Railroad in Waynesburg, PA. In early 1981, Consolidation Coal Co. (Consol) began a permitting effort aimed at building the mine. Construction began in Dec. 1981, less than six months after the first application submittal. Clean coal was produced by the Bailey preparation plant in Sept. 1984. Several factors allowed quick permitting at Bailey. Effective project planning, including early formulation of a project planning team, and identification of red flag issues helped. So did innovative responses to environmental questions, and development of environmentally sound project designs. Forming a project planning team Consol management decided that Bailey mine construction had to begin in late 1981. A project permitting team was immediately formed to see that this goal was achieved. Team members included a project manager and personnel from Consol's engineering, environmental, and operating departments. Communications among all team members was crucial in obtaining the various state and Federal environmental permits. All project permitting team members participated in weekly meetings during application preparation. Discussions at these meetings ranged from recent public contacts, to application content, to environmental design considerations. Establishing a project manager was critical to the team's success. The project manager was responsible for seeing that permit acquisition, facility construction, and operation of the mining complex proceeded on schedule. The project manager had the final word, mediated disagreements, and frequently served as project spokesman to the public. Identifying red flag issues Red flag issues are those environmental factors with the most potential for delaying the schedule or stopping the project. The first red flag issue identified was organized local opposition. This opposition had completely derailed a US Soil Conservation Service proposal to build a multipurpose dam on Enlow Fork, a short distance

Jan 9, 1985

By N. E. Norman

A great deal of effort has been put forth in recent years to arrive at accurate projections of the demands for tunnels in this decade. In reviewing the statistics presented by various study groups, it appears that during the decade from 1960-69, there were some 1,335 miles of rock and soft ground construction tunnels excavated throughout the world. These statistics indicate 645 miles of rock tunnel and 689 miles of soft ground tunnel were excavated during the last decade. This is expected to increase to 3,000 miles in the 1970's according to projections made by various authorities in the field of construction tunneling. I point out the above statistics to emphasize two main points: (1) The demands for tunneling in this decade alone are staggering. (2) There is a fairly even distribution in the amount of rock tunneling and soft ground tunneling being excavated. Unfortunately, available statistics do not answer many important questions about tunneling which are of great importance to the contractor and to boring machine designers. For example, how many of the projects completed in the past decade involved both soft ground and rock tunneling? How many projects involved tunneling in conditions where both rock and soft ground were contacted at the same face. While the answers to these questions remain unanswered, I am sure most of you can think of numerous examples of projects where mixed face conditions are prevalent. Many of you are probably familiar with the Austin Crosstown Interceptor which was bid last month in Austin, Texas. Here is a project involving 57,000 feet of tunnel where limestones and clay shales are expected to be traversed. Another project, the Tonner Tunnels No. 1 and No. 2, near Los Angeles, involve some 22,000 feet of tunnel where mixed soil and rock conditions are expected. A large majority of the projected tunnels for this decade are to

Jan 1, 1997

Sweden is beginning to reap the rewards of a process that has transformed a country with a history of metal mining into one of Europe's most vibrant exploration regions. Exploration and mining companies from North America, Europe and Australia have joined local firms in the search of gold, base metals and diamonds. This has been due to changes in Sweden's mining laws in the early 1990s. These changes opened the way for unhindered private sector investment in the country's mineral industry. More than 20,000 km2 (4.9 million acres), mainly in northern Sweden, is now held under granted or applied exploration claims. Exploration permits diamonds, applied or granted covers more than half of Sweden's surface. This is a greater proportion of the country than ever before. Major mining companies and junior explorationists are evaluating a geological potential that bears favorable comparison to other major mining centers. Historically, Sweden's gold re- sources occur in greenstone belts in northernmost Sweden and in association with massive sulfide deposits in the Skellefte district. These are receiving particular attention by exploration companies. In addition, new areas in Sweden are also being explored for gold. This increases the probability that Swedish gold production - already the highest in Europe - will increase in the future (Table 1). Sweden's recorded mining history goes back for much of the last large pool of expertise in exploration, mining, equipment manufacturing and minerals industry research. In addition, the Geological Survey of Sweden provides sup- port for exploration in terms of data archives, processing and publications. Other benefits for exploration companies are Sweden's communications infrastructure, its member- ship in the European Union, bringing access to one of the world's major markets and the high level of educational, technical and language skills held by the country's work- force. And deregulation of the economy and the introduction of competitive corporate tax rates have made Sweden a favorable destination for investment in Europe.

Jan 1, 1997

By Connie Travers, Ann Maest, James Kuipers, David Atkins

The science of predicting future water quality at hardrock mine sites has been practiced for at least the past 30 years. As part of the National Environmental Policy Act (NEPA), mines and other industrial facilities in the United States on federal land are required to estimate impacts to the environment, including direct impacts to water quality and indirect impacts that are later in time but still reasonably foreseeable (Kempton and Atkins, 2000; Bolen, 2002). Facilities on private land in the United States may also be subjected to State or federal processes that may or may not require prediction of potential impacts to water resources. Other countries have followed a similar approach, largely based on the requirements of NEPA. A wide array of scientific approaches has been used to predict water quality that could result from construction, proposed expansion, or other action at an industrial facility. In this study, we review the methods and models used to predict water quality at hardrock mine sites, with an emphasis on uncertainties associated with these techniques. Because water quantity and quality are interrelated, methods and models used to predict water quantity will also be discussed, but the emphasis will be on how these methods relate to water quality. This study brings together technical information on water-quality predictions at mine sites in a single paper, and attempts to present a straight-forward approach to using and evaluating the results of the methods and models used to predict water quality at mine sites. Approaches developed primarily in the United States, Canada, and Australia and applied in these countries and in other parts of the world, especially in the last 10 years, are discussed, and the format of the study is geared toward use by regulators of hardrock mines. The approach and results of this study could also be used by environmental managers at mine sites and community groups, and allows for the creation of a checklist for prediction methodology used at mine sites.

Jan 1, 2005

By Peter Moser, Michael Hitch, Michael Tost, Susanne Feiel

"Impact and Benefit Agreements (IBAs) are intended to be a negotiated agreement between an industrial proponent and a community, local or regional citizens’ organization. Although the elements have grown over the past two decades from a simple agreement to exceedingly complex legal frameworks, the intention remains the same: to outline the roles and responsibilities of the two stakeholders and the natural resource development on their lands beyond environmental assessment. These agreements were born out of comprehensive indigenous land claims and have become the cornerstone of community engagement today in most indigenous nations. In the case of mixed communities, those that have beneficiaries of land claims and those who are not, social acceptance remains uneven and reflective of an unequal distribution of decision-making power (political ecology). This Differential Social License can cause conflict and a breakdown of the societal fabric that binds communities of diverse populations, resulting in inequality, fictitious wealth generation and failure of infrastructure. This paper presents a case study of how the development of Differential Social License developed in the Hamlet of Cambridge Bay, Nunavut as a result of an IBA negotiated between Tahera Diamond Corp. and the Kitikmeot Inuit Organisation in 2004 for the Jericho Diamond Mine.Introduction / Background Social license (social license to operate or SLO) has become an essential part of the social governance ‘toolkit’ demanded by mining stakeholders in today’s world. Stakeholders are now insistent that companies operate more closely under the tenets of sustainable development and provide for an increased level of community participation. Social license is not simply a matter of communicating with a community, to earn its consent for or acceptance of a project. It requires that we engage with the individuals and organisations who ally themselves with communities, or who sometimes side with dissident factions of a community. SLO is a process associated with and informed by political ecology or the recognition that unequal decision-making power exists amongst stakeholders."

Jan 1, 2017

By Viacheslav Lyakhov, Cornelis H. Iestra, Victor I. Beloborodov, Vitaliy Bogdanovich

The results of a study and effective use of flotation for processing of ores with complex mineral composition containing fine-disseminated minerals with high specific density are presented in the paper. The object of research was complex baddeleyite-containing ore from Kovdor deposit (The Kola peninsula, Russia). Baddeleyite is a valuable, rare mineral, natural Zirconium dioxide with 5.8 - 6.0g / cm density, grade content 0.15 - 0.17 and dissemination less than 0.2 mm. The authors carried out a thorough investigation of baddeleyite- containing products selected in different sites of gravity flowsheet. It was determined that due to similar specific weight some sulphide minerals (pyrite, pyrrhotite) come into concentrate together with baddeleyite and, also, minerals of pyrochlores group (hatchettolite). The results obtained revealed the possibility of use the flotation for retreating rough baddeleyite concentrate. he given gravity concentrate has a number of specific features, e. g. high density of its minerals which, in its turn, provides for high speed of sedimentation of solid phase in pulp, and for the presence of large amount of sulphide minerals (up to 10%) having good flotability. With these features being taken into account a technology for flotation of baddeleyite-containing products after their preliminary gravity concentration has been developed (up to 5 - 10% Zirconium dioxide). The technology has three flotation stages. At the first one the reverse flotation of baddeleyite is carried out during which "light" minerals (forsterite. apatite and carbonites) come into froth product and at the second one flotation of sulphide minerals and at the third one direct flotation of baddeleyite is performed from the underflow product. The following reagents were used for flotation: of phosphate type (sodium tripolyphosphate, mono and diethers of alkylphosphpric acid) and sodium xanthate as collector for sulphides. The given set reagents provides for high effectiveness of flotation due to selective of collectors and presence of froth layer with high carrying ability. New flotation technology of recovering of baddeleyite from complex ore was developed and applied at the Kovdor Mining Plant, using AKER flotation machines.

Jan 1, 1995

By David A. Lindsey

The world-famous beryllium deposits at Spor Mountain, northwest of Delta, Utah, are the principal resource of beryllium in the United States. Beryllium metal, beryllium-metal alloys, and beryllium oxide ceramics have a long history of specialty applications. Beryllium is used in X-ray windows, nuclear reactors: and a wide variety of industrial and electronic products. The Spor Mountain deposits are located on the western rim of the Thomas caldera, one of at least three volcanic depressions that subsided during voluminous eruption of rhyolitic ash-flow tuff in early Oligocene time. Beginning in early Miocene time, the caldera rim and its volcanic fill were cut extensively by basin-and-range faults. Basin-and-range faulting was accompanied by local eruption of high-silica rhyolite. High-silica topaz rhyolites at Spor Mountain (21 Ma) and Topaz Mountain (6 to 7 Ma) are especially rich in fluorine and lithophile trace elements such as beryllium. Topaz rhyolite of the Miocene Spor Mountain Formation, or its magma was the source of the Spor Mountain beryllium deposits. At Spor Mountain, deposits of beryllium, as submicroscopic bertrandite, Be4Si207(OH)2, occur in rhyolite tuff beneath flows and domes of topaz rhyolite. The beryllium deposits also contain minor disseminated fluorite, lithium, uranium, and anomalous traces of other lithophile elements. The host tuff, originally composed of glass, zeolite, and abundant clasts of carbonate rock, has been altered to clay and potassium feldspar. Fluorite, quartz, and opal replaced carbonate clasts in the tuff. Beryllium was deposited with fluorite in altered clasts and in the matrix of altered tuff. Fluorspar and uranium deposits are spatially and genetically associated with the beryllium deposits at Spor Mountain. Fluorspar deposits at Spor Mountain occur mostly in breccia pipes. Some fluorspar pipes contain uranium, thought to be dispersed in the structure of fluorite. Secondary uranium minerals are dispersed throughout the tuff that hosts beryllium deposits and comprise lenses of ore-grade uranium at the Yellow Chief mine.

Jan 1, 2001

By Timothy J. Orr, Jami M. Girard

A NIOSH study on occupational deaths between 1980 and 1989 indicated that in the United States, mining had the highest average annual fatality rate (3 1.9 per 100,000 workers) of any other major industry. Since "lack of training" was often cited as the primary cause of accidents, NIOSH has been investigating new methods for effective training. One such method is the use of low- cost, desktop computers to simulate a virtual mining environment. Computer-based training offers several advantages over conventional training because the computer programs provide a three- dimensional environment that allows the trainee to practice using evacuation routes, encounter mining hazards, and view mining operations without being exposed to any real danger. One major focus of the project is mine escapeway multiuser training using desktop virtual reality programs. Researchers have imported mine maps into the software for the purpose of practicing actual evacuation routes and procedures. Various scenarios for evacuation can be practiced in a three-dimensional computer simulation of the mine in a disaster situation, complete with smoke, fire, and other dangers. Depending on the trainee's job description (i.e., foreman, shift boss, beltman, etc.), certain tasks need to be performed in addition to navigating primary and/or secondary escape routes. Each scenario allows for individual or team-based training and provides a means to educate mine workers in hazard recognition and hazard avoidance. Using this program, mine workers can practice evacuating various mine layouts without the danger and expense associated with escapeway training in an actual underground mine. Each scenario can be changed to test the trainee's reaction in a variety of circumstances and run many times so the trainee can practice concepts. This training experience will help reinforce the knowledge acquired during more conventional classroom instruction, and the inherent flexibility of the program allows training materials to be tailored to meet the specific requirements of individual mines.

Jan 1, 2002

By Thomas E. Newman

This paper is a case study using new laser-terrain-mapping technology by EagleScan, Inc., for creating topographic maps. Holnam, Inc., has used this technology to create maps and volumetric calculations of several mines in the United States. The information is superior to conventional methods through accuracy, manpower, time, and cost. Holnam, Inc., was the first cement manufacturer to use the Digital Airborne Topographic Imaging System (DATIS?). The technology uses the DATIS? to produce high-resolution terrain maps and volumetric assessments of any area. DATIS? is a mapping instrument that integrates (1) a Light Detection and Ranging (LIDAR) instrument to measure terrain elevation using laser light, (2) a large-format digital camera, (3) a relative position Global Positioning System (GPS) to measure aircraft position, and (4) an Inertial Measurement Unit (IMU) to measure aircraft attitude. The DATIS? can measure up to 220,000 elevation samples per mil. The system continually collects data on the aircraft's position and measures the time for each laser pulse transmission to return from the ground, giving each sample a GPS reference. The system can operate at night, in overcast sky, and during high-wind conditions and can measure terrain below vegetation cover, unlike standard aerial photography used for traditional surveying and mapping. Surveyed ground-control panels are no longer necessary with this new technology, and only one ground GPS base station located within 60 mi from the aircraft position is required. A computer elevation-point data file is created with the x, y, z coordinates of each laser elevation sample. With this file, CAD engineering programs can create topographic maps that rival products using conventional aerial mapping techniques. Volumetric measurements of stockpiles and pits are also available due to the high density of points collected from an area. This new technology radically changes the turnaround time for map users, giving a product in the format used by today's cartographers. The time line from flight to maps is measured in days instead of weeks.

Jan 1, 1999

By Frank P. Traczyk

INTRODUCTION The process of solid-liquid separation can be an important decision in plant design. It is very important that one must consider not only the most effective means of solids-liquid separation, but also to consider the effects on upstream and downstream processes. A solid-liquid separation is done either to remove the solids £ran the liquids as in copper concentrates or rave a liquid from the solids as in uranium operations. In either case, washing can be an important consideration to clean the solids or recover the liquids. This section will deal with solid- liquid separation other than thermal, sedimntation processes, or hydro cyclones. The three major areas discussed are pressure filters, vacuum filters, and centrifuges that are most cannon in the minerals industry. PRESSURE FILTERS Pressure filters are one common type of solid-liquid dewatering devices. There are my different types of pressure filters that are both continuous and batch operations. They are characterized by using an external pressure to push or force the slurry through porous media to force the liquids out of the solids. Whereas vacuum filters are limited to one amsphere or bar working pressure, some types of pressure filters operate as high as 16 bars pressure. Pressure filters are also effective for hot slurries where a high boiling point can be a problem or precipitation occurs under vacuum. The types of pressure filters most common in the mineral processing industry include plate and frame and recessed plate filters. Some of the new technologies including automatic pres- sure filters and belt presses are also discussed. Plate Frame Filters Plate and frame filters are one of the oldest and most effective means of both dewatering solids and clarifying liquids. Plate and frame filters consist of a skeleton that is used to hang or support alternate plates and frames that are pressed together to form chambers. The filter plates consist of a drainage grid that is covered by sane type of filter media through which a liquid is

Jan 1, 1986

It took me nearly nine months to make the move from Arizona to Berkeley, opening an office and planning our new home. While I was in Warren Dorothy had rented two rooms for my office In the new California Commercial Union Building at 315 Montgomery Street in San Francisco. She made such a good choice that this remained my address for more than 50 years Dorothy had also looked over many lots In Berkeley, and took an option on the one that pleased her the most. It was a beautiful lot, or rather three, as we took three lots to protect our view. The only possible drawback was that it was in a new district and there were only two houses within two blocks. No one could tell how the area would develop but we liked it so much that we bought the lots on the spot and signed a note to guarantee payment. Dorothy's good judgment was shown by the fact that after 50 years we are still glad to be living on the same property, at 168 Southampton Avenue. We arranged a meeting with the distinguished architect Bernard Maybeck-and employed him to design a house for us. Dorothy spent most of her time with Maybeck planning the house and an attached studio for her, and she later wrote an amusing essay on her dealings with Maybeck. They were so successful that even now we could not think of any changes we would have wanted. It took several months to design a house that suited Dorothy and would fit on our hilltop. I was glad to overcome some of Maybeck's scorn for "only an engineer" by showing how, by rotating the studio addition 45º, it would fit the lot without serious excavation. We finally signed a contract with Maybeck, borrowing so much money that it scared us. First Consulting After short jumps to the gold mines in the Secret Pass District near Kingman, Ariz., and to the Espiritu Santo prospect adjoining the rich

Jan 1, 1976

By R. K. Zipf

Recent scientific studies by researchers at the National Institute for Occupational Safety and Health (NIOSH) and the U.S. Army Corps of Engineers (USACE) presented the worst-case explosion pressures that can develop if a methane-air mixture of a certain composition and dimension accumulates and ignites within a sealed area of a mine. The Mine Safety and Health Administration (MSHA) issued its final rule on sealing of abandoned areas which considers potential explosion pressures and the risk of achieving the necessary conditions. The new MSHA seals regulation has increased the pressure design criteria an order of magnitude beyond the old standard of 140 kPa (20 psi) to 800 kPa (120 psi). However, there still are major knowledge gaps pertaining to seals and sealed areas including: (1) the composition of the sealed area atmosphere and how it changes in time and space, (2) explosion pressures that might actually develop within sealed areas, (3) engineering procedures to follow when designing seals and seal installations, and (4) guidelines to manage the atmosphere within sealed areas with monitoring or inertization. NIOSH has initiated a seals research program with collaborators from Safety in Mines Testing and Research Station (SIMTARS) in Australia, West Virginia University (WVU), the Naval Research Laboratory (NRL), and USACE. Highlights of progress so far include: (1) construction of a gas explosion tube at Lake Lynn Laboratory for studying large methane-air explosions, (2) computer simulation of the fluid dynamics of high pressure methane-air explosions, (3) development of seal analysis methods considering construction materials, reinforcement and the seal foundation, and (4) development and testing of innovative seal designs that utilize inexpensive, readily-available rock rubble to resist high explosion pressures. NIOSH researchers aim to provide sound engineering guidelines to better address the new MSHA seal regulations. DISCLAIMER: The findings and conclusions in this report have not been formally disseminated by the National Institute for Occupational Safety and Health and should not be construed to represent any agency determination or policy.

Jan 1, 2009

By C. D. Mann

INTRODUCTION The sublevel stoping mining method is usually applied to a relatively steeply dipping, competent ore body, surrounded by competent wall rock. Ore is produced by drilling and blasting longholes, which can range from 50 mm (2 in.) to 200 mm (7% in.) diam, with lengths up to 90 m (300 ft). Longholes can be inclined in any direction, but the ring or pattern usually forms a plane, and the holes are blasted as a unit. Recently developed mobile drilling and loading machinery, as well as new explosives products, blasting techniques, and cemented sand and rock fill have made sublevel stoping a highly efficient and versatile mining method. When designing a sublevel stoping production sys- tem, it should be kept in mind that production rates from conventional sublevel stopes vary widely through- out the life of the stope. Early production is at a low rate, coming only from the drawpoints near the slot, but increases as new drawpoints are reached by the stope face. As the stope nears completion, again, fewer drawpoints are productive. Enough drawpoints must be available at any time to provide required production. Drawpoint availability should be compared to equipment availability; plan for more drawpoints than are needed at any one time. Accurate, realistic scheduling is essential to smooth production rates. Also, initial recovery of ore in a stope/pillar block is normally from 35% to 50% in sublevel stoping. Planning of pillar recovery, representing the majority of ore tonnage in a production block, must be done during early mine planning. Since much of the development already done for primary stoping (access for drilling, drawpoints, and haulageways), can be used for pillar recovery, early production from pillars is highly desirable. The following description of components of the system is an attempt to highlight some of the most important features and requirements of mechanized sublevel stoping methods. Similar comments would apply to the use of older equipment (column-and-arm drill setups, slushers, etc.) in similar methods. As in any good mining system, maximum economic recovery of the resource in the ground is the primary consideration. STOPE DESIGN CHARACTERISTICS Length and Width The following are some of the factors which affect sublevel open stope length and width dimensions: ore body geometry, principal stress directions, competence of stope back, optimum drill pattern, and drilling drift layout. In new mines initial stope layout design may occur before the ore body is actually intersected by mine workings. Stope dimensioning is a critical decision, and assistance from as many knowledgeable people as possible at this stage is essential. Operators with past experience in similar ore bodies, rock mechanics experts, and others with mine design experience should participate at this stage of stope planning. Height The following are some of the factors which must be considered in determining stope height: competence of stope pillar and stope/fill walls; slenderness ratio of adjacent pillars; ore body dip; ore body thickness; hole depth capability of the drilling machine; fragmentation characteristics of the ore; and level intervals in existing mines. In competent ground, drill-hole length and accuracy are the most important determinants of stoping height. Frequently entire drilling sublevels can be eliminated because of the depth capability of sophisticated drilling equipment, resulting in significant development cost savings. Drawpoint Location and Design Some of the most important considerations of a good drawpoint system are optimum spacing of draw- points, within the constraints of stope dimensions, for uniform drawdown and maximum recovery; excavations designed for stability for the life of the ore block to be drawn-primary stope ore as well as subsequent pillar ore; floor or roadway design including type of surface, reinforcing, grade for water runoff; orientation with respect to the main haulageway, for optimum loader maneuverability and ground stability at the inter- section; and length, to allow articulated front-end loaders to work in a straight configuration. Careful drawpoint design and construction are keys to successful production. Extra care in development, such as smooth wall blasting, rockbolts or grouted rebar, wire mesh, and shotcrete usually will ensure long draw- point life. Human exposure during production loading is of longer duration than during development or production drilling, and consequently preparation of draw- points is easily justified, particularly when pillar ore can be drawn through the same drawpoints. Secondary blasting of boulders can weaken drawpoints, also justifying good ground control techniques. A smooth draw- point floor of poured, reinforced concrete, on a grade of +3% or +4% toward the ore pile facilitates water flow out of the drawpoint, and ease of loader bucket penetration into the muck pile. Slot Raising, Slotting A slot or other space for rock expansion is necessary in conventional sublevel stoping where vertical rings or rows of holes are blasted. The slot can be started at a slot raise driven by conventional raising methods, raise boring, drop raising (predrilling and blasting a raise from the top, using small diameter-less than 200-mm (7%-in.)-holes for relief), or crater blasting (similar to drop raising, but without relief holes). The slot usually extends from the extraction level to the back of the stope. It is normally expanded to full stope width by

Jan 1, 1982

By M. O?Driscoll

The tide has turned. Developments in China that have continued to unfold over the last four years or so have now reached a point where the supply market dynamics of certain industrial minerals have changed significantly. No more is this sea change better exemplified than by the supply market for magnesite, and in particular, its processed derivative grades of dead burned magnesia (DBM), caustic calcined magnesia (CCM), and fused magnesia (FM). But what has compounded the barrage of influencing factors impacting this sector, which include the widespread effects of energy and freight cost increases, has been rising demand from certain end use markets. Clearly, the magnesia market is experiencing bittersweet conditions. But those western producers which have monitored and responded to this market transformation, stand to taste success in the near and medium future. REVOLUTION IN WORLD SUPPLY STATUS In essence, while China, as host to a wealth of magnesite resources in Liaoning province, remains a huge producer of magnesia, its supply dominance on the global magnesia market has been considerably weakened. In future, it will mainly aim to supply domestic, and to some extent east Asian markets. Magnesia consumers outside China are now scrabbling for alternative, ?western? sources of supply. At the same time, magnesia producers outside China that weathered the storm of low cost Chinese DBM and FM imports flooding their regional markets for the last 20 years (and many did not), are busy investing in production capacity increases to meet not just demand from falling Chinese supply, but also demand from end use markets which is picking up. And it is not just a matter of expanding capacity of existing magnesia product lines. In the face of plentiful lower cost DBM and FM substitutes from China over the last couple of decades, many western magnesia producers started to switch their focus to the non-refractory markets (eg. environmental, specialities) which promised lucrative opportunities (and still do) and crucially, a lessening of sales revenue dependence on the DBM refractories market. Now we have the likes of Baymag (Canada), Bommag (Serbia/Turkey), and Kumas (Turkey) not only expanding capacities but seriously considering diversifying into DBM and FM production. Perhaps DSP (Israel), having ceased its famous high purity DBM activity as recently as 2005, might even reconsider a return to the ?other side?. But it?s not all DBM and FM. The CCM and specialities markets are also demanding a response, and so Baymag, DSP, Martin Marietta (USA), Premier Chemicals (USA), Qmag (Australia), MGR (Spain), and Magnifin (Austria) are also stepping up to the market on the non-refractory side. From most accounts, the situation with regard to Chinese supply has been described as one of turmoil, with prices rising, leading to improving opportunities for western producers. The majors are conducting huge expansion programmes, such as Qmag, Magnezit (Russia), and the new look Magnesita (Brazil). Even smaller players such as Causmag (Australia) and Dalmia (India) are looking to increase production. In short, the western magnesia supply sector is witnessing a landmark event in capacity investment and market share penetration as China?s previously dominant role begins to weaken (for a review of western capacity expansions see Industrial Minerals, September 2008, p.28). MERGER & ACQUISITION ACTIVITY Another response of course has been a raft of mergers and acquisitions in order to secure resources and supply outside China. These have included private equity groups taking over Magnesita and Qmag; Imerys entering the FM business through UCM; Peñoles further consolidating the electrical grade FM market by acquiring Minco; Martin Marietta acquiring Morton Salt?s Specialty Magnesia Group; Bomex entering the market through Calmag (now Bommag); LWB acquiring Magnesita; and Magnezit?s pursuit of Slovakian magnesia, with Slovmag aboard while currently wooing SMZ. Interestingly, RHI has gone ?the other way?, and has invested in a state of the art joint venture operation at Dashiqiao, Liaoning, with which it aims to secure high quality feedstock for its Chinese refractory plants. Tata Refractories Ltd has announced intentions to follow suit, and other majors, such as Qmag are known to be interested in seeking options. Naturally, there is now renewed interest from several parties in the idled 50,000 tpa DBM/10,000 CCM Jormag facility, Jordan, and the commercially undeveloped Zhargat project, Saudi Arabia. Elsewhere, there will no doubt be suitors for stakes in SMZ, in Slovakia, and Magnohrom, in Serbia, whose respective ownerships are on the block. THE ?CHINA FACTOR? The ?China factor? has been key to magnesia?s market change, and has significantly influenced prices and availability of material to global markets. Resources & production China hosts the largest share of the world?s magnesite deposits, accounting for 26% or 3,319m. tonnes of predominantly sparry magnesite (followed by North Korea, 24%, and Russia, 22%; Wilson 2008). China accounts for 44% of total world magnesite mined (19m. tonnes in 2007) and 50% of the total world magnesia produced (8.2m. tonnes CCM, DBM, FM; Wilson 2008). Russia follows China at 13% of magnesia supply, illustrating China?s dominance of magnesia production. Apart from one producer in Shandong province, central eastern China, the country?s magnesite resources and production are concentrated around the cities of Haicheng and Dashiqiao in Liaoning province, north-east China. Although there are also producers in the Xiuyan district of south-east Liaoning, the Haicheng-Dashiqiao Magnesite Belt hosts the majority of producers. In total these may number 200-300 of large,

Jan 1, 2009