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By W. Kracht

Frothers are surfactants used in floatation to aid generation of small bubbles. Studying events at the moment of bubble creation is a challenge because of the short time frame. This presentation introduces a novel acoustic approach. The technique has the resolution capable of detecting events that occur within 1-2 ms. The transition from coalescence to non-coalescence is tracked as a function of surfactant concentration and gas rate through the capillary. Results are given for some common flotation frothers and n-alcohols (C4-C8). A stress model is used to give a qualitative explanation to the observed action of frothers on coalescence prevention. Results for salt (sodium chloride) are included for comparison).

Jan 1, 2009

By R. Steele

In addition to compliance with government emissions and reporting requirements, mining and mineral processing companies are increasing energy efficiency to reduce costs and become more competitive in the global marketplace. One of the major obstacles to identifying opportunities for increased energy efficiency is the lack of readily available data on energy use, and more importantly the energy use linked to production data, that identify energy reduction opportunities. As well as energy reduction, mining and mineral processing companies often struggle with the prediction of energy use, and are often penalized for under or over forecasting. Once again, it is the lack of timely information that makes this prediction difficult. This paper looks at expanding the use of a Manufacturing Execution Systems by integrating with Energy Solutions. This will provide automatic, timely information, at a granularity that makes it easier to identify energy reduction opportunities, reduce energy costs, and better predict energy use in a mining and mineral processing operation.

Jan 1, 2011

By Jacques Nantel

Mechanization has been at the core of productivity improvements since the industrial revolution. During the past 20 years, mining has derived spectacular progress from mechanization. In the future, however, mechanization alone will not be enough. In the next few decades, automation will bring about new generations of highly productive and safe machines, with low operating costs. Increased use of new and better technology is generally accepted as the prime factor capable of closing the productivity gap. The productivity gap is the difference between inflation and metal prices. The three S-curves in Fig. I represent the evolution of technology in general, and mining in particular. TI represents incremental changes. the dominant sort of technology changes in the mining industry: - Better drills, electric hydraulic drills vs. pneumatic drills, the drilling rate is twice as fast. - Better steel and bits, to accommodate the higher performance drills. - Improved chemical explosives. - Bigger trucks in open pits.

Jan 1, 1993

By Shimi Tzobery, Jay Davenport, Raymond Henn, Sam Bandimere

Over the past several decades, the use of cement-based grouts using ultra fine cement as a replacement for portland cement has begun to gain acceptance as an alternative to chemical solution grouts used in permeation grouting. The amount of information currently available on grouts made with ultrafine cement is limited. The authors used a previously developed field testing program to perform additional tests to evaluate the permeation performance of portland and ultrafine cement-based grouts. For the first time, the 2003 testing program included an attempt to determine the 28 day compressive strength of the sand permeated by the grout.

Jan 1, 2005

By Nural Kuyucak

Several thousand years ago, metallurgists discovered that by combining two relatively soft metals, copper and tin, they could make a new material, bronze, that was stronger than either metal separately. Bronze and other alloys show how different materials can be integrated to create something new and better. Today?s mining industry can likewise find benefit in an integrated approach to managing the external impacts it has through its waste materials and its use of water. Just as using bronze gave ancient nations an economic and military advantage, mining companies can gain competitive advantage through finding better ways to manage water and waste. Trends pushing this include: ? Environmental ? Regulations on water-taking and the quality of discharged water are becoming more stringent. Net zero discharge requirements are often imposed by regulators. Mining companies also come under pressure to manage environmental impacts of mine waste, including minimizing the area occupied by waste and seepage amount resulting from infiltration of water from a smaller surface area. ? Social ? Particularly in arid parts of the world, there are multiple possible uses for each gallon of water. Local residents do not want to see a reduction in supplies of water for agricultural, domestic, manufacturing and other purposes. They get suspicious about any potential impact of water being mixed with their water reservoirs if it comes from a mining site, even if it would be treated. Such suspicions may cause conflicts among the stake-holders and delays in project approval processes.

Jan 1, 2009

By Charles W. Daugherty, James P. Gould, Kenneth R. Ware

INTRODUCTION As illustrated in Figure 1, the Washington Metropolitan Area Transit Authority's (WMATA) rapid transit system (METRO) ultimately will comprise 100 miles of line divided among 10 routes. At this time about 46 per cent of the system is under construction or in operation. Planning and design of an additional 38 per cent is at an advanced stage. Of the 84 miles under development or construction, about 10.4 miles consist of soft ground tunnels, and another 1600 feet of mixed face. This paper describes most of the factors considered by designers in setting grades for such tunnels. It is hoped the paper will be a useful guide to planners and engineers in developing similar transit systems. The problems faced in Washington, including those related to geology, are not so unique that the solutions cannot be applied to other systems. The paper also may be of interest to contractors who have not perceived the logic behind the selection of a particular vertical alignment. An attempt is made to explain the background constraints that make most tunnel alignments a compromise among competing alternatives. Readers might assume that the choice of alignments is largely controlled by geological conditions. In fact this is merely one of many factors to be considered.

Jan 1, 1976

By David Young

This paper presents tunnel design considerations for the SR75/282 Transportation Corridor Project in Coronado, California. The project is managed by the City of Coronado in cooperation with Caltrans and the US Navy and may include a one-mile long twin-tunnel section with two options: a 36.5 foot diameter twin-bored tunnel or a twin cut-and-cover box. The alignment crosses the Coronado Fault, and design provisions were needed at the fault crossing to maintain life safety and prevent rapid inundation of the tunnel in the event of fault rupture. These provisions are discussed along with considerations related to liquefaction and ground shaking. The project is currently in the planning stage with construction to start around 2012.

Jan 1, 2008

By Glen D. Frank, Jeremy P. Theys, Mina M. Shinouda, Gary W. Gilbert

PURPOSE OF THE PROJECT The Big Walnut Augmentation Rickenbacker Interceptor project began in 1995with the preparation of the Scope of Services for the design of the Rickenbacker Interceptor, with service to and around the Rickenbacker Air Force base. The air base was soon to be placed under civilian control through a Port Authority, with an expected influx of businesses and services, requiring increased sanitary service capability. Due to political differences regarding annexation and other issues, the project was placed on hold. In mid 1996 the Scope of Services was rewritten with more emphasis on a tunneling option, but still only addressing the air base and surrounding tributary are a sanitary service requirements. The consultant selection process began in late 1996 with the Request for Statements of Qualifications issued in December. Three firms were selected to furnish proposals based on the revised Scope of Services that now included requirements for hydraulic modeling of the service areas and the Big Walnut Outfall (BWO) and an expanded soil investigation requirement. All three firms were requested to make presentations to the selection committee, with the committee selecting URS Greiner for further consideration and negotiation. A contract was entered into in August of 1997with URS Greiner. The major sub-consultants were Lachel and Associates, Inc., H.R.Gray and Associates and Solar Testing Laboratories, Inc. The project began with geological investigations, preliminary soil borings, well investigations, tributary area evaluations, hydraulic modeling of the BWO system and research into other projects planned for the Rickenbacker airport and surrounding area. The hydraulic modeling of the BWO and the proposed Rickenbacker Interceptor confirmed that the BWO suffered wet weather surcharging and would require augmentation to properly convey the future flows to the Southerly Wastewater Treatment Plant(SWWTP). The project scope expanded to include evaluation of both the Rickenbacker Interceptor and the Big Walnut Augmentation projects. Both projects previously identified in the Capital Improvements Program. The work on the expanded scope for the Big Walnut Augmentation and the Rickenbacker Interceptor began with the evaluation of a parallel 2.75 meter (108") diameter augmentation sewer from SWWTP to S.R. 317and Parsons Avenue, then continuing east along S.R. 317 as the Rickenbacker Interceptor. The parallel 2.75 meter (108") sewer had been planned for in the design of

Jan 1, 2007

By E. A. Adey, C. Baciu, P. Whitbread-Abrutat, M. Varul, T. Ejdemo, R. K. Shail, F. Wall

Responsible mining requires stakeholder engagement throughout all operational stages and after mine closure. By assessing the current and anticipated future socio-economic and environmental impacts, a company can maximise the positive impacts they can have on a community, whilst minimising any negative impacts. Despite the current emphasis on companies maintaining effective stakeholder relations to gain their ‘social license’ to operate, findings of the present study reveal a wide variation in community expectations, with different degrees of ‘acceptability’ evident across seven sites in Romania (Rosia Montana), Sweden (Kristineberg), the United Kingdom (Cornwall), Bosnia Herzegovina (Vihovici) and Russia (Karabash, Gay and Mednogorsk). These variations reflect the current status of mining within a community, as well as its socio-economic background and the nature of existing engagement with mining companies already operating in the region.

Jan 1, 2011

By Dave Ragland

The SDSU tunnel and underground station are the first of these type facilities to be constructed by the Metropolitan Transit Development Board. Because there is no previous experience, and because tunneling activities are associated with some risk, he MTDB has undertaken a very proactive and wide reaching program to identify and control risks during construction. Finally, because the tunneling activity and underground station is on the San Diego State University, MTDB is working closely with their staff to identify construction impacts and mitigation’s, and thus ensure a quality project for both agencies.

Jan 1, 2001

By R. B. Berg

Montana sapphires were first discovered in alluvial deposits in the Helena area in 1865 and subsequently were discovered in other alluvial deposits in southwestern Montana and also in a lamprophyre dike at Yogo in central Montana. From about 1900 until the late 1930?s, when synthetic sapphire began to come into widespread industrial use, Montana sapphire mines produced large quantities mainly for watch bearings with lesser production for the gemstone market. The Yogo deposit is now mined for the gemstone market and two of the alluvial deposits are mined to produce sapphires for the fee-sieving of sapphire-bearing gravel and for the direct sale of gemstones. The generally pale-colored sapphires from the alluvial deposits in southwestern Montana are heated to enhance their colors whereas the generally blue sapphires from the Yogo deposit require no treatment. Markets for sapphires from both the alluvial deposits and the Yogo deposit are strong. In spite of reported historic production in excess of 70 tonnes, mineable resources appear to remain at most major deposits. Also abundant untested lamprophyre dikes in central Montana may host sapphires similar to those at the Yogo deposit.

Jan 1, 2009

By Kenneth N. Han, Peter Nam-soo Kim

A kinetic model for leaching of particulate metals in a batch system has been developed. The leaching mechanism has been analyzed by solving a series of ordinary differential equations relating heterogeneous reaction kinetics at the solid/liquid interface to mass transfer of reactant and products. Special emphasis has been given to the effect of changing of the surface area of the leaching substrate and initial particle distribution on the overall leaching rate. The dissolution of gold powders in acidic solution with bromine as an oxidant has been used as a model system. The effect of particle size, chemical reaction order, rate constant and mass transfer coefficient on the overall rate of dissolution of metal powder has been analyzed and discussed.

Jan 1, 2005

By A. Mahmoudkhani

Primary cementing is the process of placing cement in the annulus between the casing and the formations exposed to the wellbore. Portland cement was first used in 1903 in the Lopoc Field in California for well cementing. Since then, the major objective of primary cementing has always been to provide zonal isolation in oil, gas and water wells, i.e. to exclude fluid(s) in one zone from another zone in the well. To achieve this objective a hydraulic seal must be created between the casing and cement and between the cement and the formations, while at the same time preventing fluid channels in the cement sheath. This requirement makes primary cementing the most important operation performed on a well. Without complete isolation in the wellbore, the well may never reach its full producing potential. The industry knowledge on cements relies heavily on empirical data, but the chemistry, physics and structure of cement are not fully understood yet. The strength of concrete can be increased essentially by reducing its porosity through optimizing the size distribution of its components and filling the residual porosity of the hydrated cement phase with inorganic fillers. This approach has successfully utilized in different ways and several technologies for placing high performance oil and gas well cements have been developed over the last few decades. There are reasons to believe that the next source of improvement will lie in the fine-tuning of the hydrates themselves and of the different parameters that drive short (ionic?covalent bonding) and long (ionic correlation) interactions.

Jan 1, 2012

The National Mining Hall of Fame and Museum (NMHF&M) will celebrate its 25th anniversary on Sept. 22, 2012 when the 2012 class is inducted during a special ceremony in Las Vegas, NV in conjunction with MINExpo 2012. The NMHF&M will induct four men representing the equipment manufacturing, minerals exploration, copper and coal sectors of the mining industry. The diverse cross-section of mining industry giants joining the hall of fame include Glen A. Barton, J. David Lowell, Samuel Newhouse and John Cleveland Osgood. They will join 214 other mining industry pioneers when they are formally inducted into the National Mining Hall of Fame at the 25th Silver Anniversary Induction Banquet & Ceremony. These men were selected for being visionaries, leaders and ambassadors within their own sectors and across the industry at large.

Jan 1, 2013

By Jaeheon Lee, Junmo Ahn, Jae-Yeon Kim, Yoo-Jin Kim, Jiajia Wu, Eun-Woo Kim, Jai-Won Byeon, Jun-Jae Lee

The surge in demand for battery materials, coupled with environmental challenges linked to battery disposal, underscores the need to recycle spent lithium-ion batteries (LIBs). Green recycling approaches, in particular, have garnered attention for battery recycling. In this study, a hydrometallurgical method using a synergetic organic lixiviant combining methanesulfonic acid (MSA) and citric acid (CA) as an alternative to inorganic mineral acids was introduced as a green approach to recycle cathode materials of LIBs. The conditions for leaching and recovery processes were optimized. Cathode materials were regenerated using the recovered materials. Moreover, the leaching performance and economic feasibility of this leaching system were compared with those of various other organic acids.

Feb 1, 2024

By Steve Kral

When the price of gold cracked the US$9.60/g(US$300/oz) mark last year, the gold-mining industry began to crank up again. This followed several years of gold prices that had languished in the mid-200s. Existing mines increased production and mines that had lain dormant for many years were getting second looks. The United States still produces a large amount of gold. But not much of the new production is coming from that country. Instead, strict environmental regulations still have companies wary of trying to invest the millions needed to start a new mine or expand existing ones. And after years of studies and negotiations between legislators, environmental interests and the mining industry, the United States still has not crafted a new mining law.

Jan 1, 2003

By David R. Morrey

During the past 50 years, significant research has been performed in the ecology and physiology of plants that colonize soils containing elevated concentrations of heavy metals. Similar work has also been performed on plants that are able to survive acidic and saline environments. Efforts have focused on the ecological analysis of plant communities that occur over a range of metalliferous mining wastes. Investigations have been performed on the mechanisms that allow selected varieties of plant species to survive in normally phytotoxic environments and on the potential applications of metal-tolerant varieties of plant species. The purpose is the remediation and reclamation of mining wastes and soils that contain unusually high concentrations of so-called heavy metals. Characteristics of some mineral wastes Metalliferous mining wastes present special environmental restoration problems because of their toxicity. Potential toxicities are mostly caused by residual metals derived from weathering of low-grade ore or the waste products of mineral processing. In cases where pyrite forms a part of the mining waste, acid generation by oxidation may exacerbate the toxicity problem by promoting heavy-metal mobilization in aqueous solution.

Jan 1, 1995

By R. L. Virta

Ball Clay -- Four companies - H.C. Spinks Clay Co. Inc. (owned by Lhoist Group), Imerys Group (formerly Kentucky-Tennessee Clay Co.), Old Hickory Clay Co. and Unimin Corp. - mined ball clay in four states during 2010. Production, based on preliminary data, was 910 kt (1.11 million st) with an estimated value of $42.9 million. That was a 10-percent increase in tonnage from 831 kt (916 million st) with a value of $37.7 million that was produced in 2009. Tennessee was the leading producer state with 61 percent of domestic production. It was followed by Texas, Mississippi and Kentucky. About 70 percent of production was airfloat, 20 percent was crude and 10 percent was water-slurried.

Jan 1, 2011

By Sabina Brady

Investment in the ferrous sector between 1981 and 1985 will total about $9 billion, or 7.6% of the state budget for capital assets. The money will primarily go to complete the first stage of the Baoshan Iron and Steel complex and to increase steel production by 3 Mt* (3.3 million st) and seamless tubing by 0.5 Mt (551,000 st). Investment in 1983 will be about $3.5 billion, a 28% increase over 1981. Although data on nonferrous investment is less specific, the Chinese announced early this spring that the country's investment would be 2.6 times greater than the average spent during the previous five year plans. Geological surveying will also be stepped up. The Ministry of Geology and Minerals recently announced it will incorporate a search for metal and mineral resources into its second round of oil and gas surveys. The Sixth Five-Year Plan desig¬nates some actual production targets. Steel is to increase to more than 72 Mt (79.4 million st). The country's production of 10 priority nonferrous metals - aluminum (and bauxite), copper, lead, zinc, nickel, tin, antimony, mercury, magnesium, and titanium - is to increase 12.7%. Top priority is to develop aluminum production. Renewed efforts are to be made to develop gold and silver production and to increase rare earth and rare metal production. By April 1983 when the China Nonferrous Metal Industry Corp. was established, some five months after publication of the Five-Year Plan, the goals for nonferrous development had already been upgraded and changed to include: • development priority status equal to that of coal's; • an increase of more than 150% in the 1985 projected production level for the 10 top nonferrous metals (a move from the Sixth Five-year Plan's production increase of 12.7% to one of 34%); and • modification of the top 10 nonferrous metals list to include tungsten, molybdenum, and rare earths. Aluminum, copper, lead, and zinc maintained primary importance, while mercury, magnesium, and titanium were deleted. It is likely that the modification will be taken one step further and titanium will be substituted for antimony. China has already indicated its intentions to stabilize rather than expand its antimony industry, while press reports play up the titanium industry's importance to the country's development. In addition, the China Nonferrous Metal Industry Corp. announced that it expects to register a progressive annual increase of 4% in foreign currency earnings through export. China's nonferrous development efforts, therefore, appear two-pronged. First, the country's efforts will be directed toward self-sufficiency in its four major process and primary metals - aluminum, copper, zinc, and lead - and a number of other nonferrous metals that are in increasing demand by its light industry sector. At present, 96% of China's non¬ferrous consumption is composed of aluminum, copper, lead, and zinc. Substantial portions of that must be imported to meet rising demand. Second, efforts will concentrate on those metals that can be developed the fastest and are in "urgent demand" on the international market. Metals such as tungsten, tin, molybdenum, titanium, nickel, and rare earths will be given freer use of foreign capital and technology to increase production levels and raise quality. Examples of some projects in the area include upgrading the country's carbide industry and developing new high speed and tool steels to meet international standards. Foreign involvement and sales have been reported in each area, particularly with regard to sales of deposition equipment and presses by Swiss and West Ger-

Jan 8, 1983

By W. David Tyler

Any mining or engineering-construction excavation that extends below the water table must be dewatered. In many situations, the ground is of low permeability or the workings extend only a short distance below the water table. So water removal can be handled easily and economically by using mobile centrifugal pumps. However, there is an increasing number of mines that have a continuous high flow of water into the workings. Controlling this flow can significantly increase the cost of ore production. Successful implementation of any major dewatering scheme will ultimately rely on a clear understanding of the local geology. This understanding is necessary before an interpretation of ground water conditions can be made. It will dictate which dewatering methods are feasible. Once the geology and the ground water system are known, the scope and timing of the dewatering measures can be varied with the mine plan. Ground water modeling can assist in optimizing the dewatering system, though the precise objective of each model should be clearly defined. Production wells must be sited and drilled so that individual well efficiencies are high. Any lost efficiencies will translate into higher operating costs. Each well must be designed for maximum long-term control of the water table, and pumps sized to operate under continually changing heads. Finally, the investment in each production well must be protected during the mining process.

Jan 1, 1991