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By K. L. Lownie

For research and test data to serve a useful purpose, it is essential that it be derived from some known standard test procedure that allows for comparative analysis as well as independent replication and verification. Fan performance data provided by manufacturers is not absolute, and is influenced by the geometry of the test installation. For these reasons, fan test standards have been prepared in order to establish a clearly defined test procedure that allows for comparison of different fan designs, and also allows for the independent verification of test data. Internationally recognized Standards such as BS848, ISO5801, and AMCA 210 etc. are highly prescriptive, and precisely specify test duct configurations, measurement procedures, measurement planes and instrumentation to be used. Provided the laboratory tests are conducted strictly in accordance with the relevant Standard, the performance data will accurately reflect fan performance within the appropriate tolerances for efficiency, pressure and flow when tested in the defined configuration. Major differences in performance exist between a fan tested in accordance with a Fan Test Standard, and an identical fan installed in a mine ventilation system. The aerodynamic performance of any fan will be influenced by the quality of the fan manufacture, the flow system within which it is operating, the location of measurement planes, and the system stability. The flow distributions present in a standardized Laboratory test are unlikely to be repeated in mine ventilation systems, and this will also disadvantage fan performance. Unless the fan supplier takes all of these influences into account, there will an inevitable reduction in fan aerodynamic performance, and the end user will experience a shortfall in expected flow through the mine. The effect on fan performance can range from minor inconvenience to catastrophic fan failure resulting in major rectification costs and significant loss of mine production.

Jan 1, 2009

By T. Patten

Inter-Mountain Labs, IML, performed a study comparing mining waste rock sample analysis by Net Carbonate Value (NCV) and Modified Sobek acid-base accounting procedures. The study looked at 468 waste rock samples and compared the data for Neutralization Potential (NP), Acid Generation Potential (AGP), Net Neutralization Potential (NNP), and the ratio of NP/AGP. The study found that a majority of the samples were below 50 Tons CaCO3/kTons. This subset of ?low-level? samples was also examined separately for Acid Base Accounting parameters. The analysis compared the NCV procedures to the Modified Sobek procedures and concludes that the NCV procedures are as protective of the environment as Modified Sobek procedures.

Feb 27, 2013

By S. D. Bearden

Color enhances expression and communication in all physical objects experienced in life. Pigments provide color and in some applications have a specific additional function. Natural iron oxides are widely distributed throughout the world but only a few deposits are sufficiently pure and possess acceptable color and brightness properties to merit their processing into pigment form. Ochre, the common name for goethite ore, is the best and most under used material in the buff colored pigment market. The geological occurrence of ochre in the basal Shady Formation of the Cartersville Mining District (Georgia) is described. Exploration, processing, and product applications of New Riverside Ochre Company, Inc. are discussed. An overview of the worldwide pigment market is presented with emphasis placed upon the North American activity in iron oxide production and application. The purpose of this paper is to increase the awareness of ochre and its potential market in the colored iron oxide pigment industry, encourage research on the origin of ochre deposits, and stimulate interest in new applications of this unique substance.

Feb 27, 2013

By E. A. Metz

It has been approximately four years since IARC reclassified crystalline silica as a “Group One” substance. Since that time, crystalline silica has been considered a human carcinogen. Silicosis is a preventable disease and several aggressive campaigns have been developed to increase awareness of silica dust related problems in the industrial environment. New analytical techniques are being developed to determine quantitatively the amount of crystalline silica in materials. Yet, still much is to be learned about the surface properties of silica and the way in which the disease progresses into full-blown silicosis. This paper will discuss the interaction of free radicals generated by the mineral particles and lung tissue. It is the cell injury and DNA damage that progresses to fibrogenesis. Freshly fractured surfaces of silica contain free radicals. These free radicals play an important role in the stimulation of the alveolar macrophage and the development of the inflammatory reactions leading to the fibrotic response caused by silica. Engineers, scientists, and physicians need to discuss the mineralogy of silica and the technical issues concerning the development of silicosis.

Jan 1, 2000

By William R. Yernberg

The “China & East Asia Mineral and Energy Re-sources Symposium — CEAR 2000” was held Jan. 23-26, 2000 in Denver, CO. Conference sponsors included Resources and Technology Symposia of Colorado and the Asian Journal of Mining. The meeting was attended by representatives from China, Japan, Mongolia, Korea, eastern Russia (Siberia) and the United States. The US attendees consisted of interested parties from mining and energy companies, financial institutions, consultants and government agencies. In his opening statements, L. Maness, Jr., president of Resources and Technology Symposia of Colorado, said that the “goal of the conference was to make jobs and friendships and to introduce people to each other.” The conference provided an opportunity for Western mining interests, including mining companies and investors, to meet with government agencies from both sides of the Pacific.

Jan 1, 2000

By E. R. Spencer, E. R. Bauer, G. P. Cole

Overexposure to hazardous noise has been found in most mining sectors, with up to 100% of the surveyed workforce experiencing a noise dose that exceeds the U.S. 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 U.S. 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. This paper describes the development, functions and basic operation of the initial-release version of DOSES. A revised version is being developed to incorporate additional user-suggested functions, and its development and implementation to assess noise control solutions will be described in a future article. 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 on-screen 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 a worker’s noise exposure. DOSES simplifies and streamlines 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 overexposure of their workers.

Jan 1, 2011

By D. J. Gilbert

As a preventive action, the geotechnical department at the mine analyzed the original topography overlying a conveyor tunnel at the mine. Several dewatering drains were installed to intercept water collecting from an old lakebed. Subsequently, 20 steel arches were installed to provide additional support in an area of tunnel where original geological mapping indicated Type IV rock. This project was completed ontime with no loss to production. Construction schedules had to be developed to half hour precision, to accommodate the installation.

Jan 1, 2011

By G. Kim

The influence of bacterial growth phase on the flotation behavior of malachite has been investigated in a well-controlled Hallimond tube system. The microflotation tests were conducted for malachite (45?53 µm) using different amounts (bulk phase concentration=1×108?5×109 cells/mL) of Rhodococcus opacus (R. opacus) as a collector, which was grown at mid-exponential versus stationary phase, at a constant speed (340 rpm), pH (6), and malachite-bacteria interaction and flotation time (each 10 min). Hug differences between R. opacus cells in mid-exponential and stationary phase was observed from the results for electrophoretic mobility and flotation tests. Specifically, the isoelectric point of the cells in the stationary phase was lower than that in the mid-exponential phase, suggesting that the amount and distribution of surface functional groups onto cell surfaces are likely different. Additionally, the cells in stationary phase led to significant increase in the flotability compared to those in mid-exponential phase over the background bacterial concentration level of 1×108?5×109 cells/mL. Furthermore, the flotation efficiency tended to increase with increasing cell dosage for stationary phase cells while no distinct difference was observed for mid-exponential cells.

Feb 27, 2013

By R. W. Chappell, M. W. Hills, R. L. Olsen

A stochastic approach was developed and applied to the Butte, Montana Hillside abandoned mining site for modeling stormwater runoff and subsequent receiving stream loadings. This approach enabled capture and quantification of the uncertainty associated with stormwater quality data and allowed the prediction of copper and zinc concentrations in the receiving stream caused by runoff from the Butte Hillside during storm events. Runoff flows and stormwater concentrations were input to the model as probability distribution functions. Monte Carlo simulation allowed prediction of expected instream concentrations in the form of cumulative distributions functions. The modeling results allowed evaluation of current best management practices (BMPs), targeting of future BMPs, and identification of key data gaps to fill during future sampling activities. This modeling approach is considered extendable to other active and inactive mining sites. Output from a model of this type is easily understood and can be used to communicate effective stormwater management to site regulators. Furthermore, application of this modeling approach will facilitate the development and implementation of a site-specific stormwater management plan and will optimize efforts to achieve standards for compliance with stormwater discharge permits.

Jan 1, 2002

By P. C. Thakur

In Part I of this paper, it was established that the width of longwall faces in highly gassy mines is primarily limited by the volume of air reaching the tail-end of the face. The ventilation air reaching the tail-end of the face should be not only enough to keep methane concentrations below the statutory limits (generally 1 percent) but also enough to prevent any gas layering. The air volume leaking from the longwall face into the gob should also be able to push the explosive methane-air mixture away from the gob area immediately behind the longwall face where active roof-fall is taking place (typically 30-45 m). The second group of variables that also controls the width of the longwall panel consists of (a) the rate of advance, (b) bleeder air quantities, (c) specific methane emissions for the gob area and, (d) efficiency and cost of gob gas capture. This paper will discuss the second group of variables and its impact on the optimum width of longwall faces in highly gassy coal mines.

Jan 1, 2009

"2016 marks an amazing accomplishment in the mining industry as Hecla Mining Company celebrates its 125th anniversary. Mining Engineering sat down with Hecla chief executive officer Phil Baker to gain insight on this tremendous longevity and to get his view on how the company demonstrated persistence, gained perspective and created position for its future.How did Hecla Mining Co. get its start?In 1891, a group of investors formed Hecla Mining Co. to acquire and trade mining claims. No one envisioned at the time that the Coeur d’Alene Mining District would become known as the “Silver Valley” and produce more than 37.2 kt (1.2 billion oz) of silver. Or that Hecla would become the United States’ largest primary silver producer and the last of the pioneer mining companies from this illustrious mining district.What is the origin of the name “Hecla?”That will forever be a bit of a mystery. Some say it was named for an Icelandic volcano. Or that it was the foresight of James Toner, who staked the original claim, that it would go so deep, fulfilling the medieval folklore definition of the word ‘Hekla’ which is the ‘Gateway to Hell.’ I kind of like that one as the Lucky Friday Mine is almost 3.2 km (2 miles) below the surface. It has operated for more than 70 years and has all the markings of being one of only a handful of mines that will exceed 100 years of operations.Is there a common theme, or thread throughout the 125 years?Yes, Hecla has always had a solid core of high-quality and long-lived assets, positioning the company to survive times of low prices and reap the rewards when cycles turn and higher prices are realized. But it is not just assets. Hecla has extraordinary expertise that gives us the perspective of how to acquire, explore, develop and operate mining assets, particularly underground. Hecla is one of the few companies to acquire assets in the last five to six years and we did not have to write down the value of them, which means we paid a fair price for the asset despite the metals price reductions that followed the purchase. And our culture has given us the persistence to develop mines and complete projects despite lower prices. For almost a decade we have been advancing the #4 Shaft project at the Lucky Friday. We will complete this project this year, positioning the mine to operate for decades. We have elected to spend capital on San Sebastian (Durango, Mexico) and Casa Berardi (La Sarre, Quebec, Canada) to start a new mine and increase production, respectively. And we are spending money on new techniques, new equipment and innovations to our operations. Our insistence is on developing for the future, and our persistence in doing so is in contrast to many companies that are reducing investment and shrinking production"

Jun 1, 2016

We have lived through a period of strong metal pricing during the past eight to 10 years. Copper has been hovering in the range of $3-$4/lb during much of the past eight years, averaging close to $3.30/lb. Gold increased steadily from less than $300/oz levels in the early 2000s, reaching almost $1,890/oz in the third quarter of 2011, before tempering back down to the $1,200-1,400/oz range in 2013. Iron ore prices started to rise in 2005 before the staggering increases experienced in 2008- 2010, reaching almost $190/metric ton in early 2011. During the past four years, iron ore prices have ranged from $100-180/t, averaging approximately $140/t. In the aftermath of such a run, it is perhaps too easy to forget where we have come from: The copper price averaged just 77 cents/lb during the six-year period from 1998 to 2003, and averaged just over $1/lb from 1989 to 1997. The gold price averaged $350/oz during the 10-year period from 1994 to 2003. Even more dramatically, iron ore traded in the range of $10-$15/t between 1985 and 2004. So, we have seen sustained, three- to four-fold increases in copper and gold prices, and 8 to 10-fold increases in iron ore prices.

Mar 1, 2014

By William Stewart, John Tinkler, Gary B. Hemphill

Of the 345 km long Taiwan High Speed Rail Project, connecting the cities of Taipeiand Kaohsiung, the 23 km alignment on Contract C230 required the construction of5755 m of shallow mined tunnels ranging from 137 m to 1285 m in length. All nine of these tunnels were mined using NATM methodology. On September 6, 2002, a collapse occurred in Tunnel T08 that affected approximately 50 m of tunnel. There was little warning. However, the crew was evacuated approximately 45 minutes prior to failure and thus, no injuries or loss of equipment. This paper will discuss the mining methods, jet grouting ground support, and the instrumentation selected for the rehabilitation and monitoring of the tunnel.

Jan 1, 2005

By Christopher J. Vise

Although production operations at mines, representing the extraction and removal of the mined material, often appear to receive the greatest amount of attention, the emphasis given to auxiliary operations is continually increasing. This is due to the changing economic, social, and environmental climate in which modern mines must operate. Auxiliary operations can best be described as those activities that are not directly related to the extraction and removal of the mined material, but must receive proper attention if recovery is to take place in a safe, efficient, and socially responsible manner. In fact, certain mining auxiliary operations, such as strata control and ventilation, are considered to be of such importance that they warrant separate sections in this Handbook. Judging from a mine-personnel standpoint, it is not uncommon for a mine to hire the same number or more individuals responsible for auxiliary operations as the number assigned to production.

Jan 1, 2008

By J. Weyer

"Colored gemstones are most often mined in small scale artisanal mining operations. Sri Lanka is well known as source for precious stones since thousands of years. Gemstones are mine in small open pits, directly in rivers (river dredging) and in underground mines. Almost all mined deposits are alluvial deposits. PRECIOUS STONES AND DEPOSITS Precious stones from Sri Lanka are well known for thousands of years. Tales and legends from Arabia, India, China and reports from discoverers like Marco Polo describe the fabulous stones from Ceylon which was the name for Sri Lanka before 1972. Already 1000 BC King Salomon got valuable gemstones from the legendary Queen of Sheba on her visit to Jerusalem. Paintings (frescoes) of the “cloud maidens” with huge gemstones can be seen at the “mirror walls” of the Sigiriya rock fortress - one of the eight World Heritages Sites of Sri Lanka.And even today some of the most valuable and most desired gemstones come from Sri Lanka. The term “Ceylon Sapphire” stands for an excellent royal blue color of high quality corundum from Sri Lanka. Reason enough to look a bit closer how these gemstones are mined. Sri Lanka has rich gemstone deposits which are mined underground, in small open pits or directly within a river. Some of the primary deposits in magmatic and metamorphic rock are also known, but most gemstones are mined in secondary alluvial deposits. Gem bearing deposits can be found in a band from NW to SE. Highly probable deposits and main mining areas can be found around Ratnapura – the city of gems, down to the coast (Matale) and up to the region around Elahera. These secondary deposits are mostly thin layers of gravel and sand, so called “illam”. The depth can vary between some dm to 10 25 m or even almost 40 m. But the average depth is about 12 m. Gemstone mining is controlled, licensed and regulated by a special authority – the National Gem and Jewelry Authority - which was founded in 1993. Another task of this authority is the promotion and development of the gemstone industry and the control of import and export of gemstones. Any violence of the NGJA law can lead to a fine or even up to 5 years imprisonment. To increase the confidence in the gemstone industry the Authority offers a unique service to foreigners. All bought gemstones can be tested free of charge in certain laboratories in Ratnapura and Colombo. So visitors can be sure they got no imitations, wrong stones or even synthetic stones or glass. It was said that detected synthetic stones will be destroyed and the seller will do all he can to replace the stone with the right stone. Otherwise he will lose his license."

Jan 1, 2016

By J. W. Langford

A more effective method of fracturing and chipping the formation is necessary to significantly increase the productivity of blasthole drilling with a roller cone bit. The conventional rotary blasthole bit engages the formation and initiates spalls, chipping and fractures in the formation at a rate dependent on the amount of pull down force applied by the drill. The rotary speed of the drill increases the number of fractures and creates drilled chips that are removed from the hole by the air circulation. An engineering project was motivated to develop a low pressure, low impact downhole percussion hammer to provide an overstrike force to a blasthole bit, in addition to the conventional pull down force and rotary speed. The objective of the project was to utilize existing rig air packages in the range of 50-110 psig and provide an overstrike force to the bit in the range of 1100-1500 impacts per minute. Laboratory testing performed on Barre granite achieved, on average, a 40% improvement in rate of penetration. This performance has been confirmed in actual blasthole drilling in copper and iron ores mines. During the testing phase, additional unexpected benefits have also been realized.

Jan 1, 2011

"Tell us how you got involved in mining?I was first exposed to mining at a young age, as a consequence of my dad and his passion for the industry and rock collecting. Even though he graduated with a degree in mining engineering from Washington State University, my dad spent most of his career working as a structural engineer for the Boeing Company. At the time, Boeing supported a range of employee activities and clubs, including one devoted to mineral prospecting, small-scale dredging and rock hounding. My dad was extremely active in the Prospectors Club, where as a family, we spent a good part of my youth tramping around the Pacific Northwest digging for mineral specimens and panning for gemstones and gold. On my mother’s side of the family, I had relatives that mined in Dawson City and Fairbanks, AK which left a family legacy of sorts. I loved the stories that my dad and a close buddy of his, who was a geologist, would tell about various operations and towns, as well as the wild times at the annual Northwest Mining Association (NWMA) meeting in Spokane, WA. My first recollection of ever being at a commercial operation was during a tour of the Bunker Hill Mine with my dad when I was 7 or 8 years old; this had to have been shortly before the May 1972 fire at Sunshine. That visit of the mine and processing facilities made a permanent impression on me. While I always knew there was something special about the Silver Valley, I began to understand why. To this day, I still get the same feeling when I visit historic mining districts like Leadville, Morenci, Virginia City, Butte, Silverton and Barkerville. During our summer excursions to Helena, MT to dig sapphires, we would usually make visits to Butte and watch mine operations inside the Berkley Pit and surface activities at the Kelly and Mountain Con. In high school, I did well in math and science and began entertaining thoughts of pursuing a degree in engineering. Above all, I wanted to go to a college in the West that had a good academic reputation, where I could also play football. As a 6-ft, 190-lb nose guard, my options for a Division I scholarship were pretty slim, and there weren’t that many technical schools in the Northwest that were Division II that offered athletic scholarships. As fate would have it, I was unexpectedly contacted by Marv Kay, a legendary coach at the Colorado School of Mines (CSM), and was recruited to play ball. Fortunately, I had a couple of high school friends who were already attending CSM, and I had just secured a summer internship with Asamera Minerals in Wenatchee, WA. It was as if all the stars had aligned, and, with the support of my parents, I made the decision to attend Mines. Despite the stress of getting through CSM during a period when the mining industry was in freefall, it was a great decision to attend Mines, and I’m thankful for all the opportunities, friendships, and faculty mentoring I received as a student"

Mar 1, 2019

By Erich U. Petersen

Recognition of mineralogical and chemical zoning patterns associated with mineralization is an integral part of mineral exploration. Even though the origin of zoning may not always be known, zoning patterns as expressed by the systematic distribution of ore and gangue minerals, alteration or elemental assays (soil and rock geochemistry) have received much attention and are extremely useful in guiding exploration efforts toward locating economic mineralization. By contrast, the potential of using zoning information recorded in solid-solution minerals to address practical geological-engineering problems has received less attention. Solid-solution minerals can provide critical information for common problems faced in exploration, mine development and valuation. Mineral zoning information from solid-solution minerals can now be easily obtained because advances in electron microprobe instrumentation have made these instruments a most efficient, accurate, economical and practical tool for analysis of large numbers of samples. Now entire mines and districts can be studied in a timely and cost-effective manner as required by modern mineral exploration and mining practice. This article shows how knowledge of the composition of fahlore minerals can be used in addressing important problems in exploration, development and valuation. Situations are described in which drilling intersected "low grade zones" (Case one: Orcopampa, Peru, precious metal system) and where there was a need to determine the "lateral correlation of multiple ore intercepts" (Case two: Sheep Creek, Montana, sediment-hosted sulfide deposit).

Jan 1, 1992

By Michael Cruickshank

Bob Woolsey was born in 1936 in the state of Georgia and grew up to be a man of great integrity, vitality, wisdom and charm, totally neutral on matters of race, gender, and religion. A true Southern Gentleman in every sense of the word. His passing on July 9, 2008, the victim of an automobile collision, left an empty space in the hearts of his family, and his many friends and colleagues throughout the globe. The posthumous award of the Moore Medal of the International Marine Minerals Society, to Dr. J. Robert Woolsey for Excellence in the Development of Marine Minerals, is a well deserved tribute to this man who spent the last 30 years of his professional career heavily involved in research and development of marine minerals on an international basis. He first came to my attention in Burma in 1979 where, as a newly appointed technical advisor to the United Nations Development Program Offshore Exploration for Tin, I had to fill the shoes of an almost legendary figure "Dr. Bob", who accompanied by his wife Maxine had spent the previous two years initiating the program. Bob had planned to completion the construction in Singapore of a unique drilling vessel the RV Sea Drill, a spud anchored, twin-hulled barge, mounted with a Becker Drill, and designed for sampling alluvial tin deposits in the coastal waters of the Mergui Archipelago in the Andaman Sea, off Tenasserim. He had also designed and built, with the help of his side -kick Bruce Jernigan, a barge mounted dressing plant for reducing and concentrating the drill samples. The adventures of Dr. Bob in transporting the equipment to the drilling site in monsoon weather and the transfer of the drill barge from the Malaysian port of Ranong across the strait to Victoria Point in Burma with a mutinous crew will remain in the hearts and minds of his Burmese colleagues for many a long year. On his return to the States he joined, in 1980, the faculty of the University of Mississippi (UM) as assistant Professor of Geology and Geological Engineering. His prior experience in private industry and the United Nations had focused on marine mineral resources and related environmental engineering projects in Africa, South America, the Mediterranean, the South Pacific as well as south east Asia, working with dredges, mining for alluvial tin, gold, diamonds and industrial minerals. He continued to work in the area of marine minerals at UM, making a name for himself as Director of the Mississippi Mineral Resources Institute (MMRI).

Jan 1, 2008

U.S. Borax’s mine in California’s Mojave Desert is the source of nearly half the world’s supply of refined borates. These minerals are used in hundreds of products, including essential plant nutrients that increase crop yield and quality, and safe building products that protect homes from insects and the elements. Borax’s workforce is also safe. In fact, it is among the safest in the nation. In 2003, the company was recognized by the U.S. Mine, Safety and Health Administration (MSHA) for achieving the best safety record among large U.S. mining operations. It was also recognized by its parent company, Rio Tinto, for achieving the best record among its nearly 80 worldwide mining operations. Borax’s safety performance is five times better than the national average. And its workforce recently achieved more than two million hours without a lost-time injury.

Jan 1, 2004