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By J. J. Zimmerman

Over-exposure to noise remains a widespread, serious health hazard in the U.S. mining industries. Most other categories of illnesses and injuries associated with mining have improved, with the exception of hearing loss. Mine Safety and Health Administration (MSHA) coal noise data from 2000-2004 show that the continuous mining machine is first among all equipment with 35% of the noise overexposures. Joy Mining Machinery, in collaboration with the National Institute for Occupational Safety and Health (NIOSH), is conducting research to reduce noise generated by continuous mining machines. This paper describes a ?JOY Designed for Noise Reduction? (JOY-DNR; Patent Pending) tail section as a noise control for reducing the noise overexposures of continuous mining machine operators. Underground results show a 45% and 65% noise exposure reduction for the operator when compared to a standard machine. Utilizing this newly developed noise control, along with previously proven controls, will provide continuous mining machine operators an opportunity to be within the MSHA-Permissible Exposure Limit (MSHA-PEL).

Jan 1, 2010

The 28th annual American Mining Hall of Fame Awards Banquet and fundraiser sponsored by the Mining Foundation of the Southwest will be held at the Marriott University Park Hotel, Tucson, AZ on Saturday, Dec. 4, 2010. The Mining Foundation of the Southwest is a nonprofit organization whose objectives are public education about the mineral industries, and recognition of outstanding accomplishments in and contributions to the fields of mineral and fuel resources. Funds are being raised to the support the foundation?s educational programs. Among these is the Educational Outreach Program operated jointly by the foundation and the Arizona Department of Mines and Mineral Resources.

Jan 1, 2010

As metal prices fluctuated over the years, so too have the fortunes of many of those mining in Canada?s Yukon province. With a rich mining history that dates back to the Klondike gold rush of 1896 to 1898 and continues to thrive today, Yukon has experienced several ?boom-and-bust? cycles. However, during the world?s most recent mining ?bust? Yukon has held strong and has re-mained one of the world?s hottest destinations for mineral exploration. In fact, the area even exceeded forecasts in 2009, more than doubling last year. And the near-future looks just as bright.

Jan 1, 2010

By Brian Ulrich

The majority of individuals involved in the mining industry can appreciate and under-stand that mining is an activity that is necessary to satisfy the very basic needs of society, and to assist in accommodating our ever-changing world. As the expression goes, ?if it can?t be grown, it has to be mined.? And at this point in time, society has granted the mining industry the right to go about the business of mining, with the general anticipation that the work will be carried out without causing undue harm to the environment or populations in and around the mining operation. The term ?sustainable development? is gaining momentum as a popular concept, and indeed it has become something of a catch-all phrase, but it is important that the idea behind the term is not cast aside as a nonsense buzz word, as it simply is an indication that development (e.g. mining) can be satisfactorily carried out with an eye toward stewardship of the environment and society. On Feb. 19, 2010, a round-table discussion (Roundtable 2010) on ?Strides Toward Sustainability in Mining? was hosted by Knight Piésold and Co. (Knight Piésold) at the Red Lion Inn and Casino in Elko, NV. Knight Piésold had local representatives (Bryan Ulrich and Steve Boyce), as well as representatives from other office locations (Cynthia Parnow and Rick Damiani from Denver, CO, and Rick Frechette from Tucson, AZ) to help facilitate the discussion. The meeting played host to 30 attendees from five states. Attendees included personnel from nine mining properties and various corporate offices. The majority of participants were people who are directly involved with environmental work on a day-to-day basis. Others were project managers whose jobs involve some level of environmental focus.

Jan 1, 2010

By T. Hollingsworth

The Boddington Gold Mine, located near Perth in Western Australia, has recently completed the construction of a new process plant. An overland conveyor system was installed to convey the ore from the primary crusher to the process plant. This paper will discuss the overland conveyor?s mechanical design including dynamic analysis and the selection of primary mechanical and electrical components.

Jan 1, 2010

By S. P. Sandoval

In 2002 the Freeport-McMoRan Technology Center undertook research to develop a lower-cost alternative to guar for cathode smoothing in copper electrowinning. The work was conducted at the Technology Center?s SXEW Test Facility located in Morenci, Arizona. Bench-scale copper electrowinning cells were designed and implemented to screen a number of potential polymers for cathode smoothing. These included modified polysaccharide polymers that were nonionic, cationic, and anionic in nature.

Jan 1, 2010

By E. Spencer

Overexposure to hazardous noise has been found in most mining sectors, with up to 100% of the surveyed workforce experiencing a noise dose over the Mine Safety and Health Administration (MSHA) permissible exposure level (PEL). As a result, miners show elevated rates of hearing impairment of 70-90% by retirement age. To help manage noise exposures, the National Institute for Occupational Safety and Health (NIOSH) developed the Determination of Sound Exposures (DOSES) software and implementation guide for use by mine management and safety personnel. The software relies on a time-motion study that profiles the worker?s daily activities. Observations about the worker?s location and tasks or other activities are recorded along with the start and end time, to determine the duration of the tasks, so they can later be matched up with the noise data. The software gives the user the option of assessing dose relative to the MSHA PEL, the Action Level or the NIOSH Recommended Exposure Limit. The software generates a variety of interactive onscreen displays showing where, when, and how the worker?s noise dose accumulated. It also can generate customizable printed reports. These outputs can be used to highlight the tasks, locations, and times that are associated with the greatest amount of the worker?s noise exposure. DOSES simplifies the record keeping and analysis associated with time-motion studies and worker noise exposures, so mine management can make engineering noise control or administrative control decisions to limit the noise over-exposure of their workers.

Jan 1, 2010

Electronic detonators have been in commercial use for a decade, with an excellent safety record. This paper lists known incidents involving electronic detonators. Typical standards required by regulatory bodies for static electricity and electromagnetic fields are reviewed. The performance of some detonators is compared to these standards; in general the minimum standards are easily exceeded. The general resistance of electronic detonators to extraneous electrical energy that can be derived from the body of test results is compared to danger levels for exposure of humans to these energies; it is shown that electronic detonators can safely tolerate higher electrical energies than people can. This comparison includes comparable data for electric detonators, which are shown to be more vulnerable to extraneous electrical energy than people are. Electronic detonators also bring significant safety benefits in blasting due to their testability, two-way communications, reliability, programmability and precision. The links between these attributes and enhanced safety are discussed with examples from actual blasting. Although electronic detonators are usually more vulnerable to extraneous electricity than non-electric initiation systems, the paper shows that the net safety benefit in handling and blasting is in favor of electronic detonators, which are the safest initiation system that has ever been offered to the mining industry.

Jan 1, 2010

By M. J. Farrell

Mining is a significant emitter of greenhouse gases and is the focus of increasing attention from green groups and regulators. Miners need to know their own carbon emissions and how they compare with the rest of the industry. Miners and mining companies need to know where they fit in the emissions curve. Who is in the bottom quartile? This article updates data from minecost.com which detail the specific carbon dioxide emissions for over 200 mines producing 90% or more of western world copper, zinc, lead and nickel in 2009. This data shows the potential impact on mine economics of proposed carbon taxation regimes and emissions trading schemes proposed at COP 15 in Copenhagen during December.

Jan 1, 2010

The surface of chalcopyrite was studied in situ in aqueous solution by an atomic force microscopy (AFM). The AFM images showed that some absorbate in patches was detected on the mineral surface, after the chalcopyrite sample was soaked in 5x10-4M potassium ethyl xanthate (KEX) solution at pH 11 for 10 minutes. These patches increased in size with time elapsing. At the same time, as shown by the obtained AFM force curves, the adhesion between the AFM tip and the substrate increased greatly due to the adsorption. Rinsing with ethanol removed the absorbate from the chalcopyrite surface, as well as the big adhesion observed in KEX solution.

Jan 1, 2010

By T. Gollaher

The use of paste thickeners for mineral tailings has gained increasing acceptance by the mining industry throughout the world and in the U.S. during the last five years. Advantages of water recovery and environmental sustainability are the driving forces for paste as an alternative to conventional thickening and the slurry pond. This paper presents a summary of the differences between paste and conventional tailings thickeners, along with recent examples of full-scale paste thickener installations.

Jan 1, 2010

By A. S. Azman

The mining workforce experiences high rates of hazardous noise exposure and hearing loss. However, previous studies have identified specific behavioral and attitudinal barriers that keep miners from effectively acting to prevent their own hearing loss. NIOSH has developed several new hearing loss prevention tools and interventions that specifically target these barriers to prevention. The NIOSH Hearing Loss Simulator addresses motivation to take action and knowledge about the consequences of noise exposure. The QuickFit earplug test device and QuickFitWeb online hearing protection tester address barriers to effective earplug and earmuff use by verifying at least 15 decibels of protection. The NIOSH Roll-Pull-Hold technique helps miners obtain better protection through an easy-to-remember set of steps that improves attenuation by 9 decibels. The ?Inquiring Ears Want to Know? fact sheet helps miners to understand audiograms and to use them to maintain their hearing health. Each of these interventions can be used within the context of a comprehensive hearing loss prevention program.

Jan 1, 2010

By C. H. Rawlins

Deep bed media filtration is used as a tertiary treatment step (after hydrocyclones and flotation cells) to remove fine oil droplets and solids from oilfield water before reinjection disposal or to remove particulate material from surface waters used for waterflood injection. Oil and solids injection requirements are typically <5 ppm concentration at <2 micron diameter. The preferred media for produced water filtration is walnut or pecan shell, however the use of this media has evolved by trial & error and the fundamental mechanisms that occur during separation and media cleaning have not been investigated. A project was initiated to fill in this knowledge gap by analyzing the physical, mechanical, chemical, and hydrodynamic properties of six types of granular filtration media (12/20 mesh size): garnet, silica, anthracite, pecan shell, English walnut shell, and black walnut shell. Comparison of bed packing, oil wetting, attrition resistance, particle strength, and fluidization has led to an understanding of the preferred filtration media for separation of fine oil droplets and solids.

Jan 1, 2010

By D. Kelley

Due to pricing volatility and lack of availability of metals, the use of non-metallic materials of construction in metal extraction and refining processes has increased significantly in recent years Even though costs and availability of metals has improved recently, these factors are not expected to continue into the future as metal supplies once again fall short of global demand. One of the most common non-metallic materials of construction used in metal extraction and refining processes today is Fiberglass- Reinforced Plastic (FRP). These processes often require materials of construction that can resist acids and high concentrations of acid chloride salts. As shown in Table 1, FRP based on epoxy vinyl ester resin has the same chemical resistance to acid and better resistance to acid chloride salts than alloy C-276 and is superior to 2205 stainless steel in both cases.

Jan 1, 2010

New Mexico?s active coal mines have reclamation challenges that are being successfully resolved through the application of geomorphic grading methods. Soils and overburden material are often of poor quality, and annual precipitation is low. Revegetation on south and west aspect slopes often failed to persist. The New Mexico Mining and Minerals Division had therefore been encouraging topographic diversity on reclamation to improve water harvesting and reduce the percentage of south aspect slopes. Steeply dipping, multiple coal seams may be mined by open pit methods. Structurally-controlled trellis drainage patterns that exist premine have to be replaced with dendritic drainage patterns on reclamation where the overburden had been pulverized. Sodic spoil material is prone to differential settling and the creation of piping features in areas where runoff ponds, which may lead to downslope instability. In each of these scenarios, the approximation of natural drainage patterns on the reclamation has reduced erosion and sedimentation by creating shorter slopes with correct profiles, and by improving conditions for revegetation establishment.

Jan 1, 2010

Shallow ore deposits are mined by surface methods but a depth is reached in the case of most deposits after which underground methods are applied for the extraction of the remaining ore. The determination of this depth and its analysis is the subject of this paper. In order to determine transition depth from open-pit to underground mining on the basis of the allowable and economically feasible overall stripping ratios, an economic-mathematical equation is first introduced. Using the achieved equation and an analytical procedure on a particular two-dimensional hypothetical tabulate deposit, an effective formula is then established. The formula introduced here, together with the procedure adopted, could be used in all similar mining situations by the mining design engineer.

Jan 1, 2010

By M. L. Free

Acid consumption in copper heap leaching is determined by the minerals present in the ore. Gangue minerals such as biotite and chlorite consume acid together with copper-bearing minerals such as chrysocolla and malachite. Acid consumption is affected by the rate of acid application and the particle size. Some gangue minerals undergo alterations and cause precipitate formation during acid leaching. Other minerals form due to precipitation as dissolved ion concentrations from a variety of mineral sources combine to exceed saturation levels. Copper recovery is related to all of these events. This study presents information on acid consumption of various gangue minerals as well as data for copper recovery from an associated copper ore.

Jan 1, 2010

By T. A. Toney

A sampling program was conducted in 2008 to determine the run of mine characteristics of 5 coal seams. The sampling program included size analyses and float sink determinations. The samples were analyzed for ash and mercury concentrations for each size and gravity fraction. This paper will report on the sampling program, the analytical results, and the correlations determined in the data set investigated.

Jan 1, 2010

By M. Dobbins

The advent of the more efficient and effective rare-earth roll (RER) separator in the early 1980s began a new era of dry magnetic separation. The RER units quickly became the separator of choice within the materials processing industry. Though RER separators are now commonplace throughout the world, only modest advancements have been made to the original design. This paper details recent, more significant, rare-earth magnetic separation developments. These developments maintain the best features of existing technology while minimizing shortcomings. The discussion includes discerning features that aid in better metallurgical performance. Also discussed are improved mechanical aspects that allow for both easier operation and maintenance. Performance details from various test programs are included.

Jan 1, 2010

By E. Galán

The largest Spanish kaolin deposits formed on granites occur in Galicia (NW Spain) due to a widespread kaolinization of Variscan granitoids. This paper provides insight of the origin of this kaolinization process on the basis of a mineralogical and geochemical study carried out in two kaolin deposits, presently mined to be used in the paper industry. Mineral composition of the deeply kaolinized rocks is dominated by well-ordered kaolinite with minor quartz, K-feldspar, mica (illite/muscovite), locally gibbsite, and traces of resistant accessory phases (rutile, ilmenite, zircon and monazite). The content and structural order of the kaolinite decrease with depth. Kaolinite formed by extensive replacement of feldspars (plagioclase). Differential mobilization of major and trace elements during kaolinization has been inferred by using a mass-balance approach. Significant amounts of Na, Ca and minor Mn, Sr, P and U were removed from incipiently leachable minerals (plagioclase and apatite), and K, Rb, Cs and Ba were released from K-feldspar and mica. On the contrary, Ti, Zr, Th, Hf and the REE are retained in the resistant trace minerals that are concentrated in the fine fractions of the kaolins.

Jan 1, 2010