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By M. H. Weinecke, B. P. Faulkner

This paper will discuss the process for making lightweight aggregate, the waste materials that make good lightweight aggregate, the chemistry of making lightweight aggregate and finally a discussion of the commercial prospects for making lightweight aggregate from wastes. Svedala Industries has been making lightweight aggregate (LWA) from waste materials for the last ten years. Many clay-like materials, such as coal-fired boiler ash and washings from a granite quarry, can be used alone or with additional waste materials to produce a commercially saleable LWA.

Jan 1, 2001

By S. M. Carpenter

In response to the FY2008 Consolidated Appropriations Act (H.R. 2764; Public Law 110?161), the United States Environmental Protection Agency (USEPA) issued the final Mandatory Reporting of Greenhouse Gases Rule (MRR). The rule, signed by the USEPA Administrator, Lisa Jackson, on September 22, 2009, requires reporting of greenhouse gas (GHG) emissions from large sources and suppliers in the United States, and is intended to collect accurate and timely emissions data to inform future policy decisions. The MRR will go into effect on January 1, 2010, and a report of the total emissions for calendar year 2010 will be due to the USEPA by March 31, 2011. Under the final MRR, suppliers of fossil fuels or industrial greenhouse gases, manufacturers of vehicles and engines, and certain facilities that emit 25,000 metric tons or more per year of GHG emissions are required to submit annual reports to the USEPA. The gases covered by the rule are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFC), perfluorocarbons (PFC), sulfur hexafluoride (SF6), and other fluorinated gases as outlined in Table A-1 of Subpart A of the MRR, which is also provided in Appendix A of this report.

Jan 1, 2011

By R. A. Hodge

Over the past decade, there has been a significant increase in effort put to tracking progress toward sustainability. Many aspects of society are participating in this “movement” including mining. The drivers are diverse and include evolving ideas in business and public administration as well as concerns for human well-being, community robustness, environmental integrity, and overall social and ethical responsibility. The scale in question varies greatly from local to global. For the most part, there has been a pre-occupation with developing discrete measurable signals. This paper argues that the overwhelming focus on the quantitative is ill-advised and that a more effective approach is to bring together the best of both quantitative and qualitative. The mining industry in particular is well-placed to affect this shift and reap the associated benefits.

Jan 1, 2004

By J. Barrett

State-of-the-art wireless communication and location-tracking technologies will dramatically change the face of mine worker safety. The MineTracer System developed by a Liberty Lake Washington company is a broad capability wireless sensor network based on a new breed of technologies known as wireless mesh systems. In this paper, R&D Manager Jim Barrett summarizes the balance of engineering tradeoffs that result in a system that (1) performs well, (2) is survivable against many types of mine accidents, (3) operates for many hours post-accident on battery power, (4) meets stringent MSHA requirements for intrinsic safety, and (5) is economically affordable for the mines.

Jan 1, 2009

By V. Svalbonas

The process of grinding mill quality assurance brings with it associated truths and myths. When the mill quality assurance process took its first great steps forward in the late 1970s and early 1980s, they were in response to the conditions existing, in our industry, at those times. In the late 1990s, we are faced with different conditions, and problems, and need fresh solutions. Yet the system developed for the early 1980s has produced no new approaches for the late 1990s, becoming instead more hardened and entrenched. This lack of development and actual resistance to research is now costing the industry significant amounts of money in late start-ups and useless scrap loss.

Jan 1, 1999

By Bob Rautenberg

The Construction of Tunnel and Edison Force Mains contract involves the installation of two new force mains to provide a redundant means for sewage conveyance from Middlesex County Utility Authority?s (MCUA) Edison Pump Station on the northern shore of the Raritan River to the Central Wastewater Treatment Plant on the southern shore. The force mains will be installed in a 1,192 m (3,910 lineal foot) long tunnel with a 4.09 m (13'-5') inside diameter, fully gasketed precast concrete segmental lining, which is to be tunneled underneath the Raritan River utilizing an Earth Pressure Balance TBM. The tunnel is anticipated to encounter flowing soils near and beneath the river. Two new 60-inch diameter Centrifugal Cast Fiberglass Reinforced Polymer Mortar force mains will be installed within the tunnel leaving an open utility corridor above the force mains for future consideration. The project also includes the design and construction of two slurry wall shafts with associated piping. The paper will provide an overview of design and provide a case history of the construction of the tunnel and highlights of the construction methods implemented to date.

By G. Montes-Atenas

Throughout the years, research studies have reached a consensus in acknowledging the relevancy of surface chemistry phenomena on minerals separation and metals extraction. Many techniques, and notably, scanning electron microscope-based technologies have revolutionised the entire mineral processing industry. Nevertheless, the comprehensive understanding on how surface chemistry properties influence the performance of many processes involving ores is still a challenge, a matter of controversy. The latter is mainly due to the fact that all interfacial processes do not necessarily require stoichiometric and well defined atomic structures. This is particularly true in the case of sulphide minerals which are well known to be superficially unstable in aerated media. When trying to measure any variable related to mineral-mineral or mineral-aqueous solution interfaces, there are too many unknowns regarding how sensitive the interface is when facing sampling protocols and sample handling. The aim of this research work is to make a case for improving future concentrators? survey protocols. It suggests a methodology to study effectively chemical changes at the outmost mineral surface layer at different stages of a mineral processing operation. The sampling protocol and sample handling is presented in details and it is applied to the regrinding stage of an industrial plant.

Feb 27, 2013

By Wi11iam I. Rau

In the recent past, there have been numerous projections of the capital requirements for additional mine and processing capacities required to meet projected non-Communist World demand for minerals during the next 15 years. A consensus judgment would place this currently at $14 billion per year, with the largest expenditures required for increases in aluminum and copper production. Until the early 1960's, internally-generated funds were used to finance nearly all of the large mining companies' capital requirements. Since that time, however, the enormous rise in capital costs per ton of capacity, accompanied by a relative stagnation in the financial condition of many of the major mining companies, have caused the industry to begin to rely on external sources for financing expansion, most notably, project financing from commercial banks and institutional lenders. Seven years ago, it was estimated that, in the five-year period 1972-1976,75% of the total capital requirements of $10 billion per year would come from internally-generated funds, with the balance to be provided by external sources. l There is little doubt that, in the coming decade, the percentage provided by external sources will increase. There should be little difficulty in attracting the necessary investment within the U.S., particularly in view of the expected continuation of companies in diverse industries seeking mineral investment opportunities. The more serious question lies in the availability of internal and external sources of funds for the expansion of mine and smelting capacity in the developing countries. Recently, R. F. Mikesell projected an average annual investment of $4.7 billion (in 1977 prices) over the 1977-1990 period would be required from foreign sources to expand metal producing capacity in developing countries. Mikesell concluded that external financing of mining projects in the developing world has averaged less than $1 billion per year over the past five years, thereby requiring more than a quadru1ling of this financing over the next decade.

Jan 1, 1978

By A. B. Cecala

Enclosed cabs have been used on surface mining equipment for many years to protect equipment operators from health and safety hazards. The surface mining and quarrying process is a highly mechanized process that generates large quantities of respirable dust. Due to economic factors, more older mining equipment is being used today than in years past. With this older equipment, it is common to observe deterioration of many components on the enclosed cabs which greatly reduce their protection effectiveness. NIOSH has performed a number of different field studies, as well as a comprehensive laboratory study evaluating various factors and parameters regarding enclosed cabs. NIOSH has recently completed a cooperative research effort with Sy-Klone International and Vulcan Materials Company to evaluate the effectiveness of a newly designed uni-directional filtration and pressurization system that brings all the clean filtered air in at the roof of the cab and extracts all recirculated air near the floor. This design provides the highest air quality to the equipment operator. Testing on this new system showed an almost 10-fold reduction in respirable dust inside the enclosed cab. The uni-directional design is easy to incorporate and should be considered for all new and retrofit systems in surface mining equipment.

Jan 1, 2009

By R. L. Zick, D. C. Finn

Introduction The high-density sludge process was originally developed by Bethlehem Steel Corp. for use on acid mine drainage (AMD) and diluted waste pickle liquor discharges requiring continuous chemical-treatment. This work began in the early 1970s and was first put into practical use around 1973. To date, there are approximately 15 operating systems that have been installed to treat mine drainage in the United States. In addition, there are another 10 systems installed outside of the United States. The dense-sludge process is an innovative and improved method for treating acidic metal-bearing streams in a manner that minimizes the volumetric generation of sludge for disposal. The technology utilizes a sludge-recycle process that forms particles with a low affinity for water. These particles are unlike conventional metal hydroxide solids that contain tightly bound interstitial waters. Typical acid mine drainage streams contain high sulfate concentrations that combine with calcium ions in lime-based treatment systems to form gypsum crystals. Compared to the form generated in conventional lime treatment systems, the physical form of the gypsum is radically altered when the dense-sludge process is utilized. The characteristics of the metals particles are also changed in this process, as the metal hydroxides are converted to metal oxides. The dense-sludge particles settle faster, dewater more readily, are more easily pumped and hold much less water than conventional precipitates. In some cases, because the metal content of the sludge is more concentrated, it can be economically recovered. In general, the conventional and dense-sludge treatment processes are very similar. The changes required to implement the dense-sludge process are minor, and, typically, much of the existing equipment can be utilized. The net results of the process are: reduced operational costs associated with sludge generation, improved process control (particularly pH control), reduced gypsum deposition (i.e., less scaling) on system components and reduced sludge generation resulting in less return water for treatment. Despite the relative simplicity of the process, the application of the technology requires careful discrimination, and the "experience factor" for implementation is an important consideration that should not be over looked.

Jan 1, 2000

By D. R. Wilburn

This summary of international mineral exploration activities for the year 2007 draws upon available information from industry, literature and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analysis of the mineral industry based upon these data. Two types of information are reported and analyzed in this annual review of international exploration for the year 2007: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia, and 2) information on regional and site-specific exploration activities that took place in 2007 and compiled by the USGS.

Jan 1, 2008

By K. Awuah-Offei

An aggregate plant may have difficulty balancing product stockpile inventories if hot mix asphalt (HMA) design engineers do not account for aggregate inventory during mix design. Yet HMA design engineers do not, often, take this into consideration during asphalt mix design. This is due to the lack of tools that enable the lab technician or engineer to optimize the mix for good performance while helping the aggregate plant manage its stockpile inventory levels and reducing the aggregate cost. This work presents a linear programming model of the asphalt mix design problem that helps aggregate plants manage their inventory levels while meeting HMA customer demands. The algorithm is implemented in MATLAB as an Asphalt Mix Design Optimization (AMIDO) program. The program is successfully validated with real-life data. The results show that AMIDO can be used to successfully produce any mix design while reducing the cost of aggregates by using the cheapest stockpile materials. The application of AMIDO will increase aggregate plant profitability when serving HMA customers and could potentially be modified for concrete aggregate customers too.

Jan 1, 2009

By Alan Weakly

The Powder River Basin (PRB) of northeastern Wyoming and south-central Montana is the largest strippable reserve of compliant coal (0.6 or less lb of sulfur per million Btu) in the United States. In mining parlance, it is the Mother Lode! Wyoming’s portion of the Basin provides one fifth of the coal produced in the United States annually, and the state has been the nation’s top coal producer for the past six years. Based on 1993 production statistics and estimated strippable compliance coal reserves, Wyoming may remain the nation’s top producer for the next 76 plus years. Past articles on the PRB have focused mainly on production. After living and working in the Basin for the past five years, I have developed an appreciation for the area and its major industry that transcends size and production data. In the fall of 1993, MINING ENGINEERING’s publisher and I decided to present a series of articles that would cover many other aspects of the Basin. Ten topics were outlined, and specific individuals, selected for their knowledge and experience, were asked to contribute articles about their specialties. Although Montana has four large mines producing coal from the PRB, this series of articles will concentrate on the Wyoming portion of the Basin.

Jan 1, 1994

By Samer Sadek

The Georgia Department of Transportation (GDOT) undertook an exploratory feasibility study to one of the most ambitious tunneling projects in the United States. HNTB Corporation was retained to perform the study, deemed the Atlanta North-South Tunnel, which is approximately 7 miles long and consisting of four lanes (or six lanes) starting at the southern terminus of SR 400 extending to the south connecting with the northern terminus of I-675, providing substantial relief to the Downtown Connector (I-75/I-85), the most congested portion of Atlanta?s freeway system. This paper summarizes the analysis performed during the first phase of this challenging assignment which, if constructed, would be one of the longest roadway tunnels ever built in the United States.

By N. Ahmed

The collection of hydrophobic particles in the froth phase in flotation has been studied. A continuous flotation cell was developed, in which the froth phase could be isolated from the pulp zone. Hematite particles, d80 = 87 µm, were floated in the pulp, using a conventional oleate collector, while glass spheres of similar diameter, d80 = 82 µm, were introduced in wash water added to the froth. Four samples of glass spheres, with contact angles between 0 and 82 degrees, were used. The results indicate that the efficiency of collection of the hydrophobic particles in the froth can be very high. The process is strongly influenced by the hydrophobicity of the particles and the surface area available for attachment in the froth. Recommendations for the flotation of particles in the froth phase are made, especially regarding the desirable hydrophobicity as reflected in the contact angle, the froth depth, the solids concentration in the feed to the froth, the air rate and the wash water rate.

Jan 1, 2001

By D. J. Kunz

Myanmar Ivanhoe Copper Company Ltd. (MICCL) has been operating the Sabetaung- Kyisintaung (S&K) Project producing LME Grade A Copper Cathode using the Heap Leach-SX-EW Process since 1998. The mineralization is mainly Chalcocite and the mine has a life of 20 years at the designed annual production of 25,000 tonnes of cathode copper. Design capacity was achieved within two of months of start-up. The mine is among the world’s lowest cost, Heap Leach-SX-EW operations. Information regarding plant design and operation are presented along with the challenges lying ahead and the latest developments. Daniel Kunz is President and Chief Operating Officer of Ivanhoe Mines, and a director of MICCL. He has more than 20 years’ experience in mining, construction and engineering. Prior to joining Ivanhoe Mines in 1996, Mr. Kunz was Vice President and Controller of Morrison Knudsen Corporation, a major international mining and construction company. He was also President and Chief Executive Officer of MK Gold Company, a public mining company listed on NASDAQ.

Jan 1, 2001

The only significant iron ore deposit in Hungary could be found in Rudabánya. The mine was closed in 1986. The area of Rudabánya was always the home of heavy mining activity. In former times, mainly silver and other non -ferrous metals were excavated.

Jan 1, 2011

Geopolymerization is a process by which Al-Si minerals undergo dissolution and polymerization in an alkaline solution to form a monolithic material with a high mechanical strength (Davidovits, 1991; 1994). In this study, Na-feldspar (albite) and K-feldspar (microcline) have been selected to investigate their abilities to undergo geopolymerization. The interaction between alkali metals present in the alkali-feldspars and alkali metal cations contained in alkaline solution during geopolymerization has also been studied. It has been found that both albite and microcline can be applied in geopolymerization to produce geopolymers with a high compressive strength. Although the dissolution of M-feldspar (where M = Na and/or K) in concentrated MOH solution is inhibited when the alkali metal cations of the alkaline solution differ from the alkali metals structured in M-feldspar, the resulting geopolymers are found to demonstrate a higher compressive strength. Moreover, a proper molar ratio of Si/Al in the geopolymeric gel phase and a higher average hardness of the undissolved particles remaining in the geopolymers are found to greatly increase the ultimate compressive strength of the geopolymers.

Jan 1, 2002

By T. Bajpayee, L. Prosser, A. Iannacchione

Reducing the number of roof fall injuries is a goal of the NIOSH mine safety research program. Central to this effort is the development of assessment techniques that will help to identify the nature of the risks associated with working under potentially hazardous roof conditions. This paper discusses a method to determine the roof fall risk using a qualitative risk analysis technique. The ability to determine roof fall risk has been a long-standing goal of safety professionals and can provide the kind of information, needed by on-site personnel responsible for worker safety, to mitigate roof fall injuries.

Jan 1, 2007

By M. S. Delibalta, S. Kahraman, R. Comakli

The block cutting machine is one of the most important noise sources in the stone processing factories. In this study, the assessability of the noise from the block cutting machines in the stone processing factories using the P-wave velocity was investigated. The noise levels of some block cutting machines were firstly measured during the cutting of the three different rocks. Then, core samples of the same rocks were cut by an automatic cutting machine in the laboratory and noise levels were measured. A conversion factor was obtained by dividing the site noise levels by the laboratory noise levels. Then, thirty seven different rocks were cut by an automatic cutting machine in the laboratory and noise levels were measured. The P-wave velocity of rock samples were also measured in the laboratory. A strong relation between the laboratory noise levels and the P-wave velocity was found. The noise level from the block cutting machines can be assessed using the derived relation and the conversion factor.

Jan 1, 2011