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By S. Johnson

Introduction The mining of aggregates underground has grown steadily over the last 25 years. Growth has come in both production volume and in the importance this segment of the industry is playing in the continuing supply of construction aggregate. Underground aggregate mines will continue to grow in both number of operations and complexity, as the replacement of zoned reserves in metropolitan areas becomes crucial. This growth will result in a shortage of qualified mine managers, possibly limiting the success of these facilities. The aggregate industry will have to modify current practices in order to meet the growing demand for this specialized skill. Segment Growth Underground mining for aggregates is not a new idea. Martin Marietta has been operating underground mines since 1969, and currently operates 16 underground mines ranging in size from 250,000 tpy to 2,500,000 tpy. These mines represent less than 4% of the total number of operating locations, but contributed 9% of the annual production in 2004. Though they range in size and production capacity, the importance is evident. The 2000 United States Census revealed several trends that are of interest to the aggregate mining industry. For the period 1990-2000 the U.S. population grew by 33 million or 13%. There were nine major metropolitan areas with a population of five million or more. These nine areas accounted for 30% of the total U.S. population. More significant was the fact that the population growth in these nine metro areas was 25% of the growth for the entire country. These statistics tell us that the population is expanding in these major metropolitan areas at a staggering rate. The same thing is happening to some degree in every population center. Population growth increases the demand for local aggregate while reducing the available area to mine that aggregate. The need for an economical supply of aggregate to support community expansion is a problem that will grow as older quarries are mined out and closed. This will be an issue that communities of all sizes will have to deal with. A reliable and cost effective supply of quality aggregate is crucial to support community expansion.

Jan 1, 2006

By Donald P. Richards

Is a shaft the same as a tunnel and can it be approached in the same manner for design and construction? The most obvious difference between a shaft and a tunnel is that of orientation; whereas a tunnel is commonly near horizontal or slightly dipping, a shaft is commonly vertical or steeply inclined. As a result, design and construction methods employed for tunneling, in general, cannot be directly applied to shafts, although some of the basic concepts of behavior are quite similar. Many of the shafts that have been sunk in various parts of the world are owned by private mining companies. Each company has generally accumulated years of experience in shaft sinking and mining techniques pertinent to its particular geographic location. When a new shaft is to be sunk or an existing shaft deepened, the tendency often seems to be to continue to use the methods that have been used successfully in the past.

Jan 1, 1979

By C. R. Stephan

The Mine Safety and Health Administration's (MSHA) Ventilation Division continues to evaluate proposed explosion-resistant seal designs. There are currently eleven specific designs for explosion-resistant seals that are suitable for construction in underground coal mines. Seal construction in operating mines must be equivalent to those constructed in the Experimental Mine during the explosion testing program. Accidental failures of seals have occurred due to explosion pressures below 138 Kpa (20 psi). The possibility exists that the failed seals were not properly constructed. Also, conditions in the vicinity of the seals may change. Water may accumulate against the seals, heave or sag may cause detrimental effects on the seals, and sloughage of the ribs may negate hitching. If seals are not properly installed or maintained, they could fail when subjected to explosion pressures. If seals fail for any reason, the possibility exists for explosion propagation throughout large areas of the mine. There could be catastrophic consequences to an event of this nature. This report will present a limited discussion on the construction of each of these seals and will address related issues.

Jan 1, 2001

By A. A. Schweizer

This paper documents the growth and projects the future of Green Diamond Sand Products. Since1954, Green Diamond, located in Riddle, Oregon, has been producing sand from granulated nickel slag for use in various markets. Through the years, the company has seen several changes from its ownership to its product lines. In 1991, Green Diamond was producing abrasive sand at a rate of about 30,000 tons per year. It was at this time that Green Diamond became part of Glenbrook Nickel Company. Over the next eight years, Green Diamond would quadruple its production to over 140,000 tons while moving into three new markets, as well. Green Diamond is now producing sand for use in the abrasive, foundry, construction, and roofing industries. In 1998, Green Diamond again found itself under new, private ownership. With plans on developing agricultural sand and spent abrasives recycling, the future of Green Diamond appears to be one of further expansion coupled with diversification of its product lines.

Jan 1, 2000

Mining was the first economic activity carried out in Cuba, by the colonial conquerous, i.e. gold extraction from rivers and use of asphalt to calk their ships; however, due to different historic reasons only a limited development took place in this field during the colonial domination. During the republican period beginning early in this century, other interests lead to a larger scale exploitation of some known deposits. From the beginning of the century up to the triumph of the Revolution in 1959, not less than the following figures were extracted of some Cuban minerals: Refractory Chromium 3,300,000t Manganese 7,650,000 t Copper 9,000,000 t Iron 22,000,000 t Nickel 150,000 t (Ni oxide and sulphide These productions were practically directed to cover the demands of the U.S., industry and some-times these Cuban ores were almost the sole suppliers of the market.

Jan 1, 1978

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine, or for the expansion of an existing mine, can range between 9 months to 24 months, or more. The time frame will vary depending on whether an Environmental Assessment (EA) or an Environmental Impact Statement (EIS) will be completed. Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. The two year natural resource baseline study completed by Homestake Mining Company for the Ruby Hill Mine, located in Eureka County, Nevada will be used as the case study to describe how properly designed and executed natural resource baseline studies streamlined the NEPA process.

Jan 1, 2001

By Claus Becker

The new, 2.600 m long pipe under the river Elbe in Hamburg/Germany required for 2 traffic lanes, emergency lane and space for utilities a boring diameter of 14,20 m(46,6 ft). According the geology (glacial deposits consisting of clay, sand and marl, all containing big boulders) a Slurry-Shield with crusher was selected. With a minimum cover of 7 m and a maximum pressure of 5,6 bar extensive ground treatment was necessary to make the drive feasible. The machine contains a lot of new developments. The drive was finished in spring 2000 so all experiences can be reported. A special risk sharing contract avoided completely litigation.

Jan 1, 2001

By Steve Stuart

Deep-sea mineral SMS deposits present some of the world’s most challenging conditions for drilling equipment. As robotic seabed drilling services mature so too the ways that clients engage with service providers to maximise their data requirements. This presentation reviews key considerations for planning and executing a successful seabeddrilling program in variable mineralised deposits. Some of the means of collaboration between robotic seabed drilling contractors and those hiring their services are explored; where improved efficiencies and recoveries over the period of a drilling programme could be achieved. Potentially new technology or methodology can be looked at to further improve these approaches.

Sep 1, 2014

By A. L. Anderson, J. T. Rybock

Lime, soda ash and similar precipitants have been the industry standard for treatment of acid rock drainage (ARD) because of their proven ability and low per-gallon operational cost. However, these methods carry serious environmental drawbacks and high life-cycle costs. KEECO’s Silica Micro Encapsulation (SME) technology has all the positive characteristics of conventional ARD-treatment systems but none of the drawbacks. SME achieves highly effective treatment in a single step, provides options for ARD prevention and recovery of metals, requires lower capital expenditures, generates smaller volumes of higher-density sludge, consistently passes leach tests, and eliminates long-term liabilities associated with potential metal remobilization and hazardous waste landfilling.

Jan 1, 2000

By P. Todd, K. Dever, P. S. Mills, A. A. Campoli

Resin bolt performance is dependent on the size of the resin annulus, the difference between the hole and bolt radii. The vast majority of the millions of resin roof bolts installed each year in the United States employ an annulus of 0.125 or 0.188 inches. Short encapsulation pull tests with resin annuluses of 0.125 and 0.095 inch resisted an average of 2.25tons per grouted inch, with no significant variation. Resin loses to simulated fractures increased as annulus size decreased, with a minimum loss of35% and a maximum loss of 60% associated with0.188 and 0.095 inch annuluses, respectively.

Jan 1, 2000

By E. J. Berentsen

The Turquoise Ridge gold deposit is located near the Getchell Mine, 72 km (42 miles)northeast of Winnemucca, NV (Fig. 1). The deposit is owned by Getchell Gold Corp. The host rocks consist of Ordovician and Cambrian age shales and limestones. They have been crosscut by the northeast-trending Turquoise Ridge shear zone and northwest-trending shear zones. Gold mineralization occurs at depths from 427 to 671 m (1,400to 2,200 ft) along the intersection of these structures. Large tonnage, flat-lying deposits occur where folded, favorable beds are intersected by the faults. The carbonate in the beds has been replaced with silica, pyrite and arsenic sulfides.

Jan 1, 1996

By Richard L. Stotlar

Introduction During the last decade, the metallic minerals segment of the industry could be categorized as a "feast-or-famine" business. It is no secret that metallic minerals are cyclical. Employment opportunities greatly depend on the supply and demand for its mineral products. It is also not unusual for there to be a lag between the industry's manpower requirements and academia's ability to produce new graduates. Due to this lag, there will be years with manpower shortages, as in the mid-1970s. At other times, supply will exceed demand. The question is where will the jobs be in the years to come? This presentation will review reasons why employment opportunities have declined within the metallic minerals industry. It will also predict future demand for mineral engineering graduates. And it will outline strategies for obtaining an employment offer. Historical Review - Employment From 1977 through 1983, about 75% of all metal mining employees were directly engaged in production activities, down from 83% in 1965. This decline reflects increased use of labor saving equipment, and more government regulation and foreign competition. Metal mining's employment decreased from 74,000 jobs in 1982 to fewer than 68,000 in 1983 - an 8% decline. The overall industry is having these problems because of the general downturn in the economy. For example, at the beginning of this decade, US automobile and steel industries were in trouble. Interest rates were too high and volatile. This adversely affected construction, housing starts, and manufacturing. All these industries, being large users of base metals, drastically affected the metals industry. US copper companies are still having problems. Reports indicate that many copper employers have cut production, laid-off workers, and permanently closed mines, refineries, and smelters. A decline in the demand for US produced metal products, such as copper, obviously affects some mineral engineering employment opportunities. Other factors to consider when looking at employment opportunities and why it has become difficult for US metal producers to compete in the world market include: • The grades of ore bodies of many US minerals are considerably lower than the grades of ores being mined elsewhere in the world. • The grades of ore bodies currently being mined in the US are steadily declining. • Foreign producers are largely government controlled and are not necessarily subject to the realities of supply and demand. • US environmental regulations have considerably added to production costs. Foreign producers in most countries do not have to worry about these additional costs. • US mines are getting deeper. This adds to the cost of production because of the increasing distance the ore has to be transported. • Plants and equipment are outdated. Many companies find themselves operating with equipment and plants that need modernizing or replacing. This obviously hinders competitive productivity. • Labor and management have had problems. Work stoppages in certain mining businesses and high wage and benefit costs in relation to foreign producers place US producers at a disadvantage. • Much land is unavailable. The US government owns most of the land considered to have the best potential for minerals development. Most of this land is unavailable for mining or exploration. Therefore, it appears that finding employment with a company whose primary business is mining and processing most metals, such as copper, in the US will be quite restricted and competitive. Future Demand It is difficult to anticipate what key employment opportunities within the next few years will be available to mineral engineering graduates. The Engineering Manpower Commission estimated that US engineering schools awarded 72,471 undergraduate degrees in 1983 vs. 66,990 in 1982. This was the eighth consecutive year in which the number of baccalaureates awarded has increased. On a brighter note, the US government's Occupational Outlook Quarterly stated that the growth rate through 1995 for all engineers is an encouraging 49% over present levels. The estimated number of engineers employed in 1982 is 1.2 million. The numerical in-

Jan 2, 1985

By C. H. Bucknam

Principles of Green Chemistry provide useful guidance for sustainable mineral process development. Laboratory bench scale testing was carried out using pregnant cyanide leach solutions, and a number of commercially available mercury precipitation reagents were compared using jar testing to determine the most efficient and selective reagents for mercury precipitation. The most efficient reagent identified was sodium polymeric thiocarbonate (NaPTC).Coagulation experiments with fine diatomaceous earth resulted in a stable precipitate, with good settling properties. On line monitoring of the mercury in solution is recommended for process implementation to conserve reagent removing approximately 90-95% of the mercury with minimal silver and negligible gold losses.

Jan 1, 2004

By E. Bakhtavar

All parameters influencing the decision for selection of a suitable extraction method were first selected as the base of this study. Then these parameters were categorized in two main groups. The first group of the parameters includes ?geomechanical and inherent characteristics of the dimension stones? such as hardness, RQD, compressive strength, joints plane orientation and spacing, and water content. The second group was named ?technical and economical parameters associated with the investor?s objectives? like for example extraction capacity (production rate), blocks recovery, mechanization, capital investment and operational costs. Finally, the influences of all mentioned parameters on the selection of the most applicable extraction methods have been assessed and discussed.

Jan 1, 2012

By T. Geyer

The Carbon Disclosure Project (the pre-eminent global initiative for institutional investor collaboration on climate change) groups the business risks (and opportunities) related to climate change into four categories: 1. Regulatory risks from tightening legislation (and opportunities for companies that can make the carbon market work for them), e.g. rising costs for carbon and energy-intensive processes. 2. Competitive risks & opportunities generated by a possible decline in customer demand for carbon/energy intensive products (and opportunities from a consequent rise in demand for efficient / low carbon products). 3. Reputational risks from perceived inaction on climate change (and benefits to those perceived to be ?solutions providers?). 4. Physical risks from changes to climatic patterns, e.g. asset damage from extreme weather events; project delays; water scarcity; resource risks as certain crops become no longer viable in certain areas and new supply chains become necessary; and potential human and socio-political impacts. All of these are already having repercussions for businesses in certain sectors and geographies. The understanding of specific impacts of climate change is still evolving but it is clear that climate change will have a material impact on the value of many businesses, either directly or indirectly. Many commentators and analysts consider that rising energy costs are likely to represent the most direct and immediate investment risk that climate change and the resulting regulatory responses will create for business in the near term. However, it is already possible to identify numerous examples of competitive and reputational risks and opportunities that are leading to significant value creation or destruction in business: the success of the Toyota Prius; the rush by the UK?s leading supermarket retailers to ?green? their brands; and the surging fortunes of companies involved in the manufacture of renewable energy generation equipment, are all manifestations of this trend. In addition, the potential physical impacts of climate change are also making themselves felt in certain sectors: an example is the Australian wine industry, suffering after an extreme and prolonged period of drought. THE PROJECT This paper describes a project undertaken for a multinational mining company to examine the physical risks from climate change across its international business operations. The study addressed 163 components of the business and included operating sites (mines, smelters, and refineries), key transport routes (road and rail) and port links. The inclusion of the transport networks and ports is extremely important; key transport routes (e.g. a key railway link) may often be impacted (e.g. by flooding) far more than individual sites due to their large geographic exposure and multiple potential failure points. Extreme weather events causing loss of life and major economic damage continue to be front page news. According to the World Meteorological Organization, January to July 2007 ?was marked by record weather extremes in many regions across the world.? Inevitably, the associated phenomena are starting to impact business and investments, not so much as deal breakers, but in changing the parameters of risk management and the approaches required to devise mitigation measures. EXAMPLES OF EXTREME WEATHER EVENTS No one event can be presented as directly attributable evidence of climate change, however climate change projections suggest that the frequency and severity of many extreme weather events can be expected to increase in a warming world. In August 2003, a heat wave struck Europe, with temperatures as high as 42°C (108°F). As summer temperatures in much of northern Europe rarely exceed 30°C (86°F), the area was unprepared for the disaster, and many thousands of deaths occurred. In August 2005, Hurricane Katrina caused catastrophic damage along the Gulf Coast of the United States, forcing the effective abandonment of south-eastern Louisiana (including New Orleans) for up to two months and damaging oil wells that resulted in increased oil prices. Katrina killed over 1,800 people and caused at least $75 billion in damages, making it one of the costliest natural disasters of all time. This was followed in September, by Hurricane Rita which left 119 people dead along the U.S. Gulf Coast, causing $9.4 billion in damage. In January 2006, hundreds of people were killed when Russia, Eastern Europe and Scandinavia experienced the coldest weather for decades. In summer 2007, dramatic floods in the south central region of England, UK left 350,000 people without drinking water and many without electricity. Transport infrastructure was severely disrupted; combined with floods which occurred earlier in the summer in Yorkshire (North England), the damage is estimated to total over £2 billion. ASSESSING RISKS FROM CLIMATE CHANGE To date, only a minority of companies have attempted to quantify the risks from climate change. However, investors are seeking greater disclosure of climate change related risks and opportunities and it is expected companies that can demonstrate they are prepared for climate change will attract higher market valuations. Climate Change Threats A variety of climate change threats were examined for their potential to have a potential measurable impact on the mining company?s business operations. Those considered most significant were included in the study and are shown in Table 1 (see Appendix A). Certain threats can be considered as being cyclical in nature and the future predictions may suggest a change in the frequency and severity of such events (e.g. storms/hurricanes, rainfall, drought). However other threats are associated with a gradual change over time (e.g. loss of glaciers, loss of permafrost, sea level rises). A slightly different approach is needed to address this differing nature of the threats, as described subsequently. Climatic Regions Much of the research and data associated with climate change is collected and reported on a regional basis. An example of the climate change impacts predicted for a number of climatic regions is shown in Table 2 (see Appendix A).

Jan 1, 2009

By G. L. Mowrey

One critical element of the U.S. Bureau of Mines (Bureau) autonomous mining research program is the development of a reliable coal interface detection (CID) system. Several candidate CID concepts currently being investigated by the Bureau include vibration, passive infrared, radar, and natural gamma radiation (NGR). To establish which CID sensor technologies need to be developed for a given seam, coal and adjacent rock samples (i.e., immediate roof and floor) are being collected from selected major coal seams in the U.S. and are being analyzed in terms of NGR and other geophysical measurements. Results of the NGR measurements indicate that, in general, all shale and shale-like materials (e.g., drawslate, slate, and fireclay) have higher NGR readings than the coal seam. Consequently the NGR method appears to be a potentially useful CID tool, provided that the immediate roof and floor are both composed of a high percentage of shale-type material.

Jan 1, 1990

By R. P. Proulx

The Meikle Mine is a high grade, underground goldmine utilizing primary-secondary longhole open stoping with delayed backfill to produce 2700 tpd(3000 stpd) of ore. Hot and reactive ground conditions were encountered early on in the mine life. Ground temperatures up to 166°C (330°F) were measured. In the early stages of mining, the mine experienced premature detonations using different explosive products. The learning curve to safely mine this high-grade gold deposit in hot and severely reactive ground was indeed very steep. Currently, the Meikle Mine uses a special buffered bulk emulsion in all blasts to address hot and reactive ground concerns. In addition, exacting procedures are also followed to ensure safe work with explosives. The combination of new explosives technology and strict loading procedures permits high mine productivity with the highest degree of safety.

Jan 1, 2000

By Andy Alder

The aim of this paper is to provide an overview and details of good practice, from a United Kingdom perspective, in the development and implementation of major tunnel and underground infrastructure projects. In doing so, it draws on a broad base of project management theory. A central theme is that successful project delivery is dependent on detailed planning of the complete project delivery process, forming an effective team that works well together and the proper management of risk. The role of partnering in forming a strong project coalition is described. Particular emphasis is given to the integration of design and construction, and the role of the designer throughout the construction phase. The implementation of risk management in the design and construction of tunnel works is discussed, and recommendations are made on how risk, value and constructability can be integrated in project delivery. Recent practice in project procurement, particularly in the use of innovative collaborative forms of contract are described, and details of particular provisions for joint management of risk and problem resolution are provided. Finally, the relevance of the ITIG Code of Practice for Risk Management of Tunnel Works to good practice in project delivery is highlighted throughout the paper.

By S. J. Neethling

The flotation froth structure and motion determines the amount of entrained gangue that is collected to the concentrate. Despite this important role in the overall performance, the behaviour of the froth is still ill understood. To date, predominantly empirical models have been developed to describe entrainment. A fundamentally based model is described and used here in an attempt to improve the understanding of entrainment. This general froth simulator (UMIST FrothSim) allows the modelling of a wide range of flotation conditions, as it takes account of a large number of the physical phenomena that occur within flotation froths. The model firstly describes gas motion and bubble coalescence, and the water motion based on gravitational, viscous and capillary effects. The motion of the solids distinguishes between various solids classes based on hydrophobicity, particle size and density and models them by including the effects of Geometric and Plateau border dispersion, particle settling and the motion of the water. The aim of this paper is to show the applicability of this model to explain the observed entrainment and collection of gangue. This is done by comparing model predictions with the experimentally observed relationship between the gangue and water recoveries. The model predicts the identical trends, which are explained in terms of the interaction between the linear effects of water motion and hindered settling and the non-linear effect of particle dispersion.

Jan 1, 2001

By R. G. McLusky

This paper analyzes the opinion in Bragg v. Robertson, 72 F.Supp. 2d 642 (S.D. W.Va. 1999), a case which threatens the future of surface mining in West Virginia and which will almost certainly result in new policies or rules that will affect surface mining everywhere. This paper addresses: (1) the jurisdictional bases of the action which relies on the federal surface mining laws to enforce a state mining program; (2) settlement agreements reached in the case that threaten to alter federal policies beyond West Virginia borders; (3) a programmatic environmental impact statement on mountaintop mining being undertaken by the federal government; and (4) an opinion by the Court outlawing excess spoil disposal in intermittent and perennial streams.

Jan 1, 2001