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Partition models are commonly used to assess the separation performance of circuits incorporating density-based processes. Unfortunately, this useful tool has traditionally been overlooked by the heavy minerals sands industry due to difficulties associated with the use of toxic dense liquids. In the present study, this problem has been avoided via the development of partition models based on experimental data from microscopic grain-counts. This technique, which uses different mineral species as density tracers, provides a new tool for evaluating the multi-stage circuits that are required to successfully upgrade heavy mineral sands. The partition model approach easily identifies shortcomings of existing circuits and, when used with conjunction with linear circuit analysis, provides tremendous insight regarding the optimum arrangement of unit operations in terms of separation efficiency and plant throughput capacity. An industrial case involving the redesign of a heavy mineral sand spiral plant is presented to demonstrate the utility of these process engineering tools in plant optimization.

Jan 1, 2009

In this work, the crystallization of Carnallite from waste brine of Qaidam Basin in Qinghai province was studied based on NaCl-KCl-MgCl2-H2O phase diagram. According to this study, a new crystallization pathway to recycling waste brine was developed. The carnallite salt was formed by using this technology during the waste brine evaporation. The experiment data shows that 5 tons of waste brine was required to form one ton of the carnallite. The average grade of carnallite prepared by using this procedure was about 19.40% of KCl, 16.92% of NaCl, 28.80% of MgCl2, and 0.82% of CaSO4. This study provides an opportunity to utilization of the waste brine.

Jan 1, 2012

By T. Patten

A method for stabilizing mercury containing waste for landfill disposal would be a very cost effective solution for industry. A mercury polythiocarbonate material which is made via a metallurgical process passes a traditional TCLP for mercury. The mercury polythiocarbonate material was subjected to a more thorough evaluation, the Integrated Leaching procedures as described in Kossan (1) and Sanchez (2)The procedure involves leaching the mercury polythiocarbonate material at varying pH and sample size to liquid. The procedure had to be adapted for small sample sizes and finely divided materials due to the product characteristics and available material. The leachates were evaluated and found to be stable within common environmental pH values. The performance details on how Inter-Mountain Labs met the leaching requirements of the procedures and the analysis of mercury are presented.

Jan 1, 2012

By L. Hoffman, F. Seymour, S. Hoerger

Newmont has a large integrated operation in Northern Nevada with numerous mines, stockpiles, and processing facilities. There are over ninety defined metallurgical ore types and over sixty defined gold recovery process options. To take better advantage of the available synergies, a complete Nevada wide mine plan and process model along with a mixed Integer and Linear Programming optimization tool has been developed and implemented. This system is maintained and operated by a Nevada Planning Group. Standard in-house planning software tools and methods have been implemented at all mine sites. While increasing the effectiveness of planning in Nevada, these changes have allowed a significant reduction in overall Mine Engineering staff.

Jan 1, 1999

By B. S. Pierce

The National Coal Resource Assessment – 2000 project was a multi-year effort by the U.S. Geological Survey to identify, characterize, and assess the coal resources that will supply a major part of the Nation’s energy needs during the 21st century. The purpose of the USGS National Coal Resource Assessment (NCRA) was to (1) digitally assess selected coal beds and zones that will be the most important in the next few decades, (2) create publically available stratigraphic, geochemical, and geographic information system (GIS) databases to answer a variety of questions of importance to government, industry and public decision makers, and (3) provide interpretive geologic and geochemical information for the primary coal resources of the Nation. Five priority regions were assessed: the Appalachian Basin, Illinois Basin, Gulf Coast, Illinois Basin, and Northern Rocky Mountains and Great Plains. The NCRA was a cooperative effort between the USGS and a number of State geological surveys in these coal-bearing regions. A study of coal resources on Federal lands was also conducted. Adequate energy supplies and the efficient use of those supplies are critical to the economic well being of a country. Affordable and reliable coal supplies are essential to the interests of our national and local policymakers. Policy makers require a range of information on the energy supply, as well as the economic and environmental issues associated with that energy source and its use. Formulation of an effective national energy policy and development of energy resources requires that we understand the geology, distribution, quality, and size of the national energy endowment.

Jan 1, 2001

Over 800 mines have closed in Australia in the past 25 years. This paper summarizes the data obtained from those closures and includes all Australian States and Territories and all commodities, including metalliferous, coal and industrial minerals. Twenty five percent of the mines closed due to resource exhaustion or depletion; 24% due to high costs, price drops, or declining grades; 8% due to open pit resource depletion (but with underground reserves remaining) or underground reserves depleted (but plans to open cut remainder) and 7% due to receivership or voluntary administration. The environmental, social and economic impacts of these closures are also significant and include acid mine drainage and impact on mine employees. An understanding of the causes of premature mine closure will better equip mining companies and governments to better manage future mine closures, wherever in the world the mines are operating.

Jan 1, 2007

By David E. Siskind

The Bureau of Mines has studied the problem of cracking in residential structure walls from vibrations produced by blasting in surface mines. Direct observations were made of blasting damage consisting primarily of cosmetic cracking in plaster and gypsum board walls. Measurements of structure response and also application of the response spectra analysis single-degree-of-freedom model were used to quantify the frequency dependence of the safe level criteria. An overall summary analysis was performed using the new Bureau of Mines damage observations and data obtained from nine previous studies, including the three analyzed earlier by the BuMines for Bulletin 656, published in 1971. Separate analysis of the high- and low-frequency damage cases, structural response, and two types of construction resulted in the establishment of safe vibration levels ranging from 12 mm/sec to 50 mm/sec (0.5 in/sec to 2.0 in/sec).

Jan 1, 1980

By John Reilly

The author?s paper at RETC 2007, ?Alternative Contracting Methods? addressed strengths and weaknesses of DBB+DB and introduced Construction Manager/General Contractor (Portland model) and Alliancing (Australian model). Considerable interest in these was expressed by several public agencies at that Conference and at the presentation. The author is assisting the Washington State Department of Transportation (WSDOT) and the Toronto Waterfront Revitalization Corporation (TWRC) with possible implementation of Alliancing. WSDOT is evaluating ways to do this and is considering a delivery methodology, under existing Legislation, based on the CMGC Portland model with incentives and disincentives, moving towards Alliancing. This paper will build on the 2007 paper and update implementation considerations.

Jan 1, 2008

By D. J. Carpenter

Safe and successful mine closure represents a fundamental work element that needs to accommodate the geochemical conditions existing at the completion of the mining and ore processing effort. Given the interests in limiting costs and time associated with mine closure efforts enhanced prior understanding of the geochemical conditions likely to exist upon exhaustion of the economic reserves can provide important benefits. The purpose of this paper is to document the benefits associated with geochemical modeling and understanding how the ore formation process may impact mine closure efforts, using one ore deposit type as an example. Specifically, this paper will emphasize the geochemical processes leading to the formation of sandstone-hosted uranium roll-type deposits and how the resultant concentrations and distributions of ore and gangue phases need to be incorporated into understanding the geochemical conditions projected to exist at the end of mineral recovery efforts. The paper will describe the evolution of geochemical conditions leading to ore body formation and the geochemical effects induced by open pit mining and how these may be used to understand both the geochemical controls and constraints on residual mine water. In addition, a discussion will be provided on how these conditions may be simulated by solution equilibria and kinetic modeling to develop optimum approaches to achieve applicable closure standards. This paper will also discuss specific augmentations to existing industry standard solution equilibria and kinetic models and associated thermodynamic databases to maximize the predictive accuracy of the geochemical modeling results. The benefits of understanding the electrochemically reactive behavior of uranium and associated gangue phases and incorporating this behavior into mine closure efforts will be presented. The culmination of the benefits of the geochemical modeling will ultimately be the development of a sustainable approach to uranium mine closure that is based upon an engineered environment designed to return the ore body to stable geochemical conditions.

Feb 27, 2013

By R. L. Kloberdanz

Peruvian legislation requires the preparation of an Environmental Impact Study (EIS) for new and expanding mines/beneficiation facilities and the preparation and implementation of an Environmental Adjustment and Management Program (PAMA) to control and mitigate environmental impacts associated with existing mining/beneficiation activities. Shepherd Miller, Inc., developed guidance documents for preparing an EIS and PAMA for Peru's Ministry of Energy and Mines and presented workshops to Peru's mining industry on preparing an EIS and PAMA. This paper discusses the process and approach taken and the results.

Jan 1, 1998

By R. Oler

The mining industry?s traditional preference for protective coatings in corrosive environments, due to cost considerations, has been to apply galvanized and epoxy coatings. As a result of extreme pH levels and the limitations of current products, a new coating has been developed to withstand severe conditions. Harsh chemicals and corrosive groundwater pose added challenges to mines in maintaining long term ground support which demands continuous rehabilitation. This paper highlights the challenges and identifies a solution by applying a new economic coating to DSI?s Omega Bolt? that withstands the most corrosive of conditions. [ ]

Jan 1, 2012

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 M. Lohk, Y. -. R. Pastarus

Oil shale industry of Estonia provides a significant contribution to the country’s economy, but causes a large number of different problems. In spite of high economical parameters of the current underground mining (room-and-pillar) technology it is not effective. Backfill technology will be applicable in condition of Estonian oil shale mines. Nowadays attention has been focused on the use of combustion and mining by-products as filling materials. Use of ash and limestone in mining industry is treated as a part of mining technology, not as a waste disposal. Underground utilization of wastes reduces the volume and area required for surface disposal, environmental taxes. It improves the quality of mining works. The use of backfill technology has great impact on mining practice in Estonian oil shale industry.

Jan 1, 2011

Ground falls (roof and rib) have historically been responsible for about 50% of all fatalities in bituminous underground coal mines. In some recent years, the number of ground fall fatalities has approached zero, indicating that significant progress has been made. On the other hand, last year?s Crandall Canyon twin mine disasters, in which 9 miners perished in violent coal bumps, provided a stark reminder that complacency is premature. One important success has been a great reduction in the number of miners killed inby roof supports. Throughout the 1990?s these accounted for nearly half of all roof fall fatalities, but there have just been two inby incidents in the past 5 years. Progress has also been made in pillar recovery. Safer mining technologies have reduced the number of fatal incidents, but some recent failures have underlined the need for careful management of the retreat mining process. On the other hand, more than 400 miners continue to be injured each year by rock falling from between supports, and 100 more are injured by rib falls. Together, these two categories also account for a large percentage of recent ground fall fatalities. Available technologies such as roof screen, rib bolting, and inside control roof bolters could dramatically reduce injury and fatality rates if they were used more widely. Further advances in these areas will likely be the next big advance in ground control safety. 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

Perhaps the most significant development in China's base metal sector is the discovery of major copper porphyries in northern Jiangxi Province and the adjacent southern Anhui Province. At the center of the new exciting district is the proposed Dexing copper complex, located some 350 km east of Nanchang, the provincial capital of Jiangxi. This project represents China's first attempt to put together a major large-scale open-pit operation, comparable in magnitude to Arizona porphyry operations. With the aid of Fluor Mining and Metals, the Chinese plan to develop a 135-175 kt/d open-pit mine, a matching large-scale mill, and the infrastructure needed to accommodate the big operations. An operation of this magnitude would significantly reduce China's import requirements by some 75%. China imports of the red metal are running around 200 kt/a. Under the direction of the Ministry of Metallurgical Industry, the Chinese are currently operating a 10-kt/d mine and mill with equipment primarily of Chinese origin. Dexing engineers told ME that they are considering a possible scale-up to 20 kt/d. How this effort will ultimately jell with the major expansion program is largely a matter of conjecture. Fluor Mining and Metals received a $10-million contract in December 1978 to develop a preliminary engineering and design program. While the original plans called for a 175-kt/d capacity complex, the Chinese subsequently decided to scale it down somewhat. The current proposal is around a 135 kt/d, which would in- elude the existing operation, according to Dexing engineers. Completion of the engineering and design phase is expected by March 1980 and a go-ahead decision will likely be made at that time. The value of the engineering and construction contract is estimated between $800 million and $1 billion. At right, mined ore is dumped 150 m down the mountain to a holding pocket below for rail haulage to the processing plant. Below, a Chinese miner tackles the universal problem of hard toes in the pit with a jack leg. Reserves and Early History The Dexing mineralization consists of three principal ore bodies, including the Chushahung on the north mountain, and the Tungchang and Fuchiawu on the south mountain. Combined ore reserves are estimated by mine geologists at 1.7 Gt of 0.4-0.5% copper. As is characteristic of porphyries, the ore contains important associated values of molybdenum, rhenium, pyrite, gold, and silver. There is also some secondary calcocite and bornite with an oxidized capping. Historically, copper was recovered with iron from the pregnant solutions emanating from the Tungchang deposit as early as the Tang Dynasty (700 AD). Modern day exploration was conducted by the Bureau of Geology in 1956 and reserve figures were es-

Jan 3, 1980

By S. M. Pickering, L. T. Gregg

Appraisal of industrial minerals beneath privately owned land requires a different approach and mindset from valuation of base and precious metals or energy minerals, and from valuation of government-owned mineral lands. First, is it the value of inground minerals or of mining rights that is being sought? Second, value to whom, the mining company, a potential investor, the mineral landowner, a lending institution, the property tax assessor, or a condemnor? Third, how should mineral value be apportioned between the land and mineral owner, and a mining company with limited years of lease-hold interest? These and many other questions must be addressed before a valuation method and Discount Rate are selected. For various reasons the Income Method is most often used, with Net Present Value calculations made for long term predicted mining income. Choice of an appropriate Discount Rate is critical.

Jan 1, 2000

By Y. Xi

In this paper we present an availability approach for determining the capacity of a major bucket wheel excavator (BWE) system to be used in Yuabaoshan surface coal mine in China. Based on previous time studies on other BWE systems for delay times due to internal and external causes, and a four-level maintenance and repair schedule, we develop a model taking into account all random failures and present a fast and simple solution to this highly complex problem. A procedure employing the Markov renewal theory for determination of the distribution of random failure times and failure rate of the whole system, as well as some other factors useful for calculation of the overall system capacity are discussed in the paper.

Jan 1, 1993

By R. Lawrence

Mineral property valuations to be used for Canadian securities regulatory purposes must comply with CIMVal1. The technical basis for a CIMVal report is the same as that required for a technical report that complies with NI 43-1012. NI 43-101 describes the content to be covered in a technical report, while also covering other requirements, one of which is that the report should be based on a property visit. CIMVal is based on five tenets that the valuator must follow: ? Materiality. ? Independence. ? Transparency. ? Competence. ? Reasonableness. Upon its adoption by CIM Council in 2003, it was hoped that the new CIMVal code would be adopted without change by the several Canadian regulators.

Jan 1, 2011

By Donald Bishko

Zoning is the legal means by which land use can be controlled. Although zoning laws have historically been quick to prevent quarrying, one is hard pressed to find zoning ordinances which specifically state that land should be used (or held in reserve) for quarrying and prevent other uses such as recreation, housing, etc. This situation is especially true when the mineral to be quarried has a low intrinsic value such as sand, gravel, and crushed stone. The chance of a gold mine surviving urban sprawl is probably considerably greater than that of a sand and gravel pit, even though it is possible that the dollar value of the sand and gravel' would exceed that of the gold mine. The research reported herein was concerned with two major topics: to delineate the real costs associated with the non-protection of our construction aggregate resources (growth minerals) and to develop a computer simulation model which would aid planners in making economically sound decisions. This paper describes the problems faced by the mineral aggregate industry and discusses the role of computer simulation in planning problems. It briefly describes a simulation model which has been developed and previously reported12 and discusses the results of a pilot study conducted on the Tri-City area (Albany, Schenectady, and Troy, New York). 3

Jan 1, 1970

By E. M. Spokes

A.B. Rushton The work and resulting publications of the Committee on Underground Coal Mine Safety and The President's Commission on Coal were appropriate at the time of publication. The statistics cited in the publications appeared to be valid, and the actions proposed by the committee had merit. Although the actions proposed to achieve further improvements in safety may have been worthy of repeating, to associate statistics (Table 1) that are seven to eight years old with company names is bad. Statistics are readily available from the Mine Safety and Health Administration (MSHA) and are usually within three months of being up to date. A review of the most recent Coal Controlling Co. Report will reveal significant changes in the rankings. The more recent statistics should have been cited, or at least compared with those used in the article. Westmoreland Coal Co. is listed as having a 21.1 disabling injury rate for the period (1/78-12/80). The disabling injury rate for the Company for the year ending 1985 was 7.4 for the underground mines and 6.25 for the total facilities. Through March 1986, the disabling rate for the underground mines was 2.86. The management and employees of Westmoreland Coal Co. are committed to safety. The improvements achieved over the past five years attest to that commitment. We are justifiably proud of the achievement and dislike being misrepresented as in the April 1986 article. Reply by E.M. Spokes I regret that the lapse of time since the original work gives a picture of safety practice that is no longer true today. That Westmoreland has reduced its disabling injury rate by 65% to 7.4 in 1985 is most commendable, and I congratulate you for this accomplishment. It is typical of the progress sought by the National Academy of Science and National Research Council when they funded the original study and published "Toward Safer Underground Coal Mines" in 1982. If a significant number of companies do as well as Westmoreland, the report will have served its purpose. Since the paper was primarily a condensation of the original report, it would not have been appropriate to seek access to later statistics. The purpose in seeking its publication at the time of presentation was to reach those who might have missed the original report. The fact that publication was delayed has not voided that purpose and may have reminded some who were aware of the original that its recommendations still apply to improvement of underground coal mine safety.

Jan 6, 1986