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By Rodolfo Lagos, Nicos Pfeiffer, Ben Harding, Clayton V. Deutsch

This paper outlines a cutting-edge probabilistic resource modeling workflow tailored to the Round Mountain epithermal gold deposit. The primary goal is to craft a robust and modern simulation process that enables the quantification and comprehension of anticipated discrepancies during mining reconciliation, offering a more precise gauge of expected gold quantities compared to conventional estimation models.

Dec 1, 2023

By Sahendra Ram, Ashok Kumar, Rakesh Kumar, AMIT KUMAR SINGH, Dheeraj Kumar, Arun Kumar Singh, Rajendra Singh

This paper describes the successful mechanized extraction of coal pillars in 11 panels using the fish-tail method from 2010 to 2017 at Pinoura Mine in India. This method proved its potential of coal recovery with efficient strata control under weak roof due to faster rate of extraction in a single lift. Observations of strata and snook behavior during the field studies in different panels of the mine are included.

"The National Mining Hall of Fame and Museum (NMHFM) announced the 2018 National Mining Hall of Fame inductees. This year’s inductees, selected by the National Mining Hall of Fame’s Board of Governors, represent exploration, extraction, management, education and research and development in the U.S. mining industry. Their contributions have had significant and lasting impacts on the mineral and mining industry; these individuals were selected for being mavericks, thought leaders, researchers, educators, mentors, wealth builders and philanthropists.Professor John M. Guilbert, Dr. Leo J. Miller, Robert E. (Bob) Murray and Douglas (Doug) B. Silver will join 240 other mining industry luminaries when formally inducted into the National Mining Hall of Fame on Sept. 29, 2018. Additionally, the Prazen Living Legend of Mining Award will be presented to the Freeport- McMoRan Foundation. The 31st Annual Induction Banquet and Ceremony will be held at the Ritz-Carlton in Denver, CO.2018 National Mining Hall of Fame inducteesProfessor John M. Guilbert was a renowned geologist and professor of economic geology at the University of Arizona; he had a distinguished 50-plus year career in academia and business. Guilbert, together with J. David Lowell, worked on the most important breakthrough in mineral exploration in the last 100 years, the Porphyry Copper Model. This work, known as the Lowell and Guilbert Model, was utilized by exploration geologists worldwide over the next four decades to discover hundreds of millions of tons of copper metal and numerous profitable mines including the prosperous Bajo de la Alumbrera copper mine in Argentina. Guilbert was a founder of The World Museum of Mining in Butte, MT. He was the recipient of countless awards including the Society of Economic Geologists (SEG) R.A.F. Penrose Medal as well as the D.C. Jackling Award from the SME.Dr. Leo J. Miller was a maverick in the mining industry and no armchair geologist. He believed that active fieldwork, on foot with a rock pick, was indispensable for exploration. His basic tenet was to absorb as much information about an exploration target up front, formulate ideas – sometimes novel ones — and then get out into the field to prove those ideas. Miller was known to diverge from the standard interpretation of the geological processes, which formed the mineral deposits, and to apply innovative applications of high-tech tools to more usual exploration programs. This approach resulted in a 50-plus year career that included the discovery of the Kidd Creek massive sulfide deposit and the development of the Lee Creek phosphate deposit; which other explorers had previously given up on, believing whatever phosphate might be present would be too difficult and expensive to mine. The recipient of many honors and awards, Miller received the SME Robert M. Dreyer award in recognition of outstanding achievement in ore discoveries."

Jan 8, 2018

By J. D. McKendrick

Alaska's Arctic Slope lies between the Brooks Range and Beaufort Sea and is a region about the size of Nebraska. It has some of Alaska's richest hydrocarbon deposits. In addition to containing petroleum and natural gas. Much of the area west from the Colville River has low-sulfur coal deposits which are shallow enough for surface mining. Developing those resources will require a firm and realistic' commitment to protecting and rehabilitating the natural habitats. Balancing such a commitment with economic constraints in a practical sense requires knowledge of the environment and its associated biological components, i.e. the soil/water-plant-animal relationships.

Jan 1, 1988

By D. R. Hembree

This paper discusses the mineralogy and metallurgy of the Kuroko-style volcanogenic massive sulfide ores mined at Formosa Exploration Inc. I s Silver Butte Mine located in southwest Oregon. The principle ore type is pyrite + chalcopyrite + sphalerite, while subsidiary pyrite + bornite + sphalerite ore is also mined. The two styles of mineralization have distinctly different metallurgical behaviors and must be treated separately. Selective flotation methods are used to produce copper and zinc concentrates from the first ore type, while bulk concentrates are produced from the bornite ore. Careful mine planning and coordination between the mine and mill are utilized to achieve optimal recoveries.

Jan 1, 1993

By J. R. Muhm

Environmental due diligence investigations, also known as Phase I Environmental Audits, are increasingly important to major investors, venture partners, or prospective purchasers or sellers of mineral properties. Knowledge of environmental risks associated with a property will allow better appraisal of a property's overall desirability prior to completing the transaction. It is possible that the cost of environmental cleanup could exceed the value of the property. Topics appropriately investigated include permit status, water quality, past use of the property, hazardous materials management, storage tanks, public records pertaining to the environmental character of the property, and environmental costs.

Jan 1, 1991

By P. Todd, K. Dever, P. S. Mills, A. A. Campoli

Resin bolt performance is dependent on the size of the resin annulus, i.e., the difference between the hole and bolt radii. The majority of the millions of resin roof bolts installed each year in the United States employ an annulus of 3.175 or 4.775 mm (0.125 or 0.188 in.). Short encapsulation pull tests with resin annuli of 3.175 and 2.413 mm (0.125 and 0.095 in.) resisted an average of 0.08 t/grouted mm (2.25 st/grouted in.) with no significant variation. Resin loses to simulated fractures increased as annulus size decreased.

Jan 1, 2003

By Jeffery L. Kohler

A method of monitoring production, information, i.e., raw tonnage and machine state, from each working section has been developed. The method is based on the sensing of electrical parameters in each section load center, and the reporting of this information through the existing mine-wide monitoring system. A decision-theoretic type of pattern classification technique has been used to define the machine states. The basis of the method is presented in this paper, along with a proposed hardware and software implementation scheme. Information issues central to the development and use of the proposed production monitoring system are also discussed.

Jan 1, 1988

By D. R. East

The concept of sub-aerial tailings deposit.ion using a managed rotational deposition system to form a deposit of partly-saturated tails for North American conditions was introduced by Knight and described by Knight and Haile (1983). The application of the sub-aerial technique, together with continuous removal of all surface waters and underdrainage outflows from the Key Lake uranium mine I s tailing storage facility in Northern Saskatchewan, Canada, has been documented by Knight and Haile (1984). Since then, the concept is being applied in the United States to tailings facilities in California, Nevada, Arizona, Utah, Colorado, Idaho and South Dakota.

Jan 1, 1989

By A. J. Monhemius, R. G. Reddy, G. W. Warren, E. Peters

Thermodynamic solubility of chromium in pickling solutions (i.e., HF- HN03-H2O solutions) was determined as a function of HF and HNO3 acid concentrations at 298K. Pure Cr, AISI type 316 and 416 stainless steel were used in this study. The results showed that the solubility of Cr increased with increase in the concentrations of HF and HNO3 acids in solutions. The solubility of Cr increased in the order of pure Cr > 416 SS > 316 SS. The theoretically calculated Cr solubility data were in reasonable agreement with the experimental data.

Jan 1, 1993

By Hans von Michaelis

Welcome to RANDOL GOLD FORUM 88. It is clear from the list of delegates and speakers that this conference will lead to excellent discussions of the latest developments in this fast-moving industry. Less than a year ago Randol International Ltd. published an eleven-volume report titled "Innovations in Gold and Silver Recovery - Phase 111". In the short space of time since then, many new developments have been noted, many of which will be described in this Forum. I believe that some of the more significant innovations currently under development are those that address the following:

Jan 1, 1998

By M. S. Hunter, Al Bishop

In 1994, Lone Tree Mine invited Hunter Hawk to participate in a problem-solving arena at their mine located in Valmy, Nevada. Lone Tree was experiencing consistency problems with autoclave valve component quality and delivery. Based upon a prior working relationship at Homestake Mining Company's McLauglin Mine, located in Lake County, California, both customer and vendor enjoyed a measure of rap­po1i and trust - the keys to problem solving communication. This paper is an overview of the problem solving process that has contributed to Lone Tree's excellent record of 95 per cent autoclave availability since 1995.

Jan 1, 1998

By R. E. Gundersen

I have to express my surprise and must send a note of warning concerning the use of polyurethane foam as described in a paper by R.N. Torbin and R.F. Kovar, entitled "Innovative Shaft Lining Method," published in your February 1989 edition. In September, 1986, 177 miners lost their lives when they were exposed to fumes downwind from a fire in a tunnel lined with polyurethane foam. Whilst polyurethane exhibits reasonable fire retardent properties in small-scale tests, mass use in a tubular configuration, exacerbated by the furnace effect of cross-radiation, can lead to a rapid, uncontrollable conflagration.

Jan 1, 1990

The bromine review did not arrive in time for publication in the June issue. Bromine production in the United States during 1992 amounted to 171 kt (376 million lbs), a 453-t (I-million lb) increase from 1991. Data compiled by the US Bureau of Mines indicates this increase was due mainly to greater exports of elemental bromine and bromine derivatives (flame retardants). Exports increased despite the economic slowdown in Europe and Japan. The United States remains the world's largest bromine producer, with about 42% of the total. Israel is ranked second, followed by the United Kingdom, the former Soviet Union and Japan.

Jan 1, 1993

By Robert Klug, Nils Engelke

"In order to extract proportionately small quantities of valuable minerals, mining companies move large amounts of earth. A resulting waste product of this process has traditionally been stored in a semi-liquid phase known as tailings, typically stored in a large pond created by an earthen dam at the low end of a drainage basin. It is generally expected that these dams are stable enough to withstand the pressure of the stored material. Unfortunately, history shows us that this is not always the case. The Baia Mare dam in Romania failed in 2000, causing tragic and prolonged environmental damage to several major European rivers. The Bento Rodrigues dam in Brazil failed on Nov. 5, 2015, and that event resulted in the loss of 16 lives.In hard rock mining, many minerals are imbedded within the ore. As part of the mining process, valuable minerals are extracted from the ore; often, the mineral content is only a fraction of the total ore volume processed. To extract the minerals, the ore is typically crushed and pulverized into very fine particles, then wetted to form slurries. The minerals are extracted from the slurries through a series of flotation and/or sedimentation steps with the aid of water-soluble separation chemicals typically known as reagents. Following the mineral extraction, the resulting residual wetted ore cuttings are labeled as tailings. At the end of the extraction process, the tailings are in a thick semi-fluid sludge state, often with trace elements of the extraction reagents.Historically, these tailings are deposited in giant basins or sludge ponds, where they pose a great threat to the environment while binding large volumes of waste process water.Process water recovery and achievingdry tailingsCurrent generation engineering studies, trials and successful field implementation have shown that an alternate process known as dry stacking is practical. The dry stacking process deposits dewatered tailings into containment areas that are smaller in overall footprint and significantly safer by reducing the transfer of reagents into the tailings storage area. In addition to achieving the dry tailing benefits mentioned, it is possible to recover valuable process water while dewatering the tailings sludge utilizing modern separation technology."

Jan 4, 2018

By K. Chandrasekaran

Carbon-in-Leach (CIL) is conventionally used in gold processing operations when preg robbing components are present in the ore. CIL process is becoming attractive even in other situations when preg robbing is not a factor. This paper discusses the situations in which the CIL circuit can be applied. The results of Leach/CIP and CIL circuits at Newmont's Mill No.2, 4 and 5 are presented for comparison. Newmont's Mill No. 4 was initially designed for a throughput of 4500 tons per day. The mill is presently operating at an average throughput of 7300 tons per day without significant changes to the original design. The design considerations of the Mill No.4 CIL circuit are discussed.

Jan 1, 1991

By S. A. Saki, J. F. Brune

"INTRODUCTION Longwall coal mining leaves large areas where the coal has been made removed and the roof rock strata collapse, forming a zone of broken rock rubble called the gob. Figure 1 shows a typical longwall gob area along with the gate roads. The ventilation pattern for progressively sealed longwall panels follows a simple “U” pattern where fresh air is coursed inby to the headgate, flows along the face and exhausts through the outby tailgate as shown in figure 1(a). An important variation of this pattern is the back return (BR) arrangement where the exhaust air from the face is drawn inby and around the nearest open cross cut before it turns in the outby direction towards the exhaust fan. Figure 1(b) illustrates the use of back return. This arrangement moves the point of low pressure from the tailgate corner up to 60 m inby and thus maintains fresh air in the tailgate region that could otherwise be contaminated with gob air.The gob area may contain remnants of unmined coal or parts of overlying coal beds that continue to release methane, eventually filling the gob area with methane in concentrations far above the explosive range of about 4.5 to 15%. Many gob areas must be equipped with gob ventilation boreholes (GVBs) to extract methane, and GVBs often exhaust methane at concentrations from 50% to 90% (Saki, 2016). Due to oxidation processes occurring in the gob, the oxygen content is reduced to a low level, with nitrogen and CO2 making up the major remaining components of the gob atmosphere. FORMATION OF EXPLOSIVE GAS ZONES IN GOBS Since the longwall face area is ventilated with fresh air below 1% methane and the face and gob areas are not separated, an explosive fringe will form where the methane content lies within the explosive range and oxygen content remains above 12%. Figure 2 shows a typical development of such an EGZ. This figure is based on a computational fluid dynamics (CFD) model developed by CSM researchers to analyze gas concentrations and flow patterns in longwall mining. Figure 2(a) shows the formation of EGZ in the gob with a U type ventilation scheme, where EGZ lies right behind the shields in the tailgate corner. Figure 2(b) shows the formation of EGZ in the gob combining U type ventilation scheme with BR, where EGZ is pushed away from the face deep into the gob. The CFD modeling parameters and boundary conditions have been verified with field data from two cooperating, active longwall mines (see Worrall 2012, Marts 2015, Gilmore 2015 and Saki 2016). Other mine geometries, methane inflow rates and gob permeability distributions can be modeled to establish representative gob atmospheric conditions. Two GVBs were operating in the model, extracting 0.165 m3/sec each. The methane in the working areas and returns was kept below 1%. Methane flowing into the model from a rider coal bed above the mined seam was at the rate of 0.55 m3/sec."

Jan 1, 2017

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 Alan C. Richter

Introduction The East-West Gateway Coordinating Council is an organization of local governments formed in 1965 to identify regional problems and to formulate policies, plans and programs to resolve them. The major goal of the Gateway Council is to improve the quality of life for the citizens of the St. Louis Region. While East-West Gateway Coordinating Council is the organization I represent and it only deals with the St. Louis Metropolitan Area, you will find one or more similar organizations in each of our nation's urbanized areas. As a result, for illustrative purposes, I will use my organization to portray what is happening nationwide. For example, in order to eliminate duplication, the Council reviews local applications for approximately 100 federally funded programs in such areas as highways, mass transit, parks, water treatment, and sewers before they can be sent to the appropriate funding agency. The Council's varied functions place it in a unique position of receiving more and more responsibility for developing strategies of implementation of various environmental regulations. This is due to the fact that environmental control is a relatively new field and we, as a country, are relatively inexperienced. The resulting regulations and guidelines will depend, to a great extent, on what the general public is willing to accept in terms of controls and what price they are willing to pay in terms of taxes and increased costs. Land Use: Growth vs No Growth This is perhaps the most encompassing environmental issue. We, as a nation, are beginning to realize that land is a limited natural resource and that the way we choose to use 'this resource affects many other aspects of our lives--whether we can catch edible fish in the Mississippi, how much we pay for sewer services, if we can swim in a

Jan 1, 1977

By J. Kretschmann

According to the model of product life cycles, the global coal mining industry is in the stagnation phase. The coal demand of the main consumer, China, has peaked in 2013 and is slowly declining. The Norwegian sovereign wealth fund, the world´s largest, has excluded coal-related companies for ethical reasons. Important players like the UN or the EU have already begun to describe pathways towards de-carbonization. Increasing competition between coal mining companies and the mining regions can be expected worldwide if companies want to keep their positions on the global and national coal markets. Companies will focus on the best deposits. European countries like France, Spain or Germany are only forerunners of this development - their centuries of coal production have been finished. The concept of Sustainable Development (SD) is fundamentally based on a model of progress where ecological, economic and social dimensions should be developed equally and positively. But without the idea of competition, the concept of SD is incomplete. Questions arise, such as: How can SD be realized on stagnating or declining markets without guarantees for companies “to live forever”? How can SD be a corporate goal in a phase of decline? How can declining mining regions sustainably progress into a better future? The German hard coal mining industry´s lifecycle has ended in 2018 after 60 years of stagnation and decline. As of 2019, all hard coal consumed in Germany will be imported, especially from Colombia, Russia and South Africa. What has been done in Germany to handle the coal decline in a sustainable way and the lessons learned from this process is described in this paper. It may be useful for mining regions who will face a similar future sooner or later. INTRODUCTION Principally, mining natural resources is a finite business that reaches its limits once the deposits mined are depleted, the resources can no longer be mined in an economically profitable way, or substitutes are pushing the mined products out of the market. An example for the latter is the increasing replacement of coal with natural gas and renewables in power generation in the USA. (Kok 2017) According to the model of the product lifecycle, the global mining hard coal mining industry has reached the stagnation phase. (Kretschmann 2000) Although the coal mining business is more a multi-regional than a global business the trend is obvious. The peak of coal use is behind us, especially because the coal demand of China is slowly decreasing since 2013. (Shell 2018) China´s government has announced investing $360 billion in renewable energy by 2020 and scrap plans to build 85 coal-fired power plants. In March 2018, Chinese authorities reported that the country was already exceeding official targets for energy efficiency, carbon intensity, and the share of clean energy sources. China’s energy regulator, the National Energy Administration, rolled out new measures to reduce the country’s dependence on coal. (Kejun and Woetzel 2017) Coal consumption in the US is facing a 16 % decline in five years from 800 to 670 million short tons between 2015 and 2019 and - according to the EIA – will not rise again. (EIA 2018) The decline is attributed to complex market dynamics from low gas prices because of the “shale gas revolution” (Kok 2017, p. 3) to federal environmental regulation like the Clean Power Plan. The United Nations´ UNEP Finance Initiative is cooperating with the Portfolio Decarbonization Coalition of institutional investors to implement decarbonization strategies across their portfolio. Amongst these investors is the New York State Common Retirement Fund, the third largest public pension plan in the USA. (UNEP 2017) The European Union has already begun to de-scribe pathways to decarbonization. (European Union 2018) The Norwegian sovereign wealth fund, the world´s largest, excluded coal-related companies for ethical reasons. The oil giants Total S.A. and Royal Dutch Shell, tradi

Jan 1, 2019