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By Gerald M. Ellis

ntroduction As the gold mining industry continues to develop in the Dominican Republic and Haiti, more deposits will undoubtedly be discovered that will be amenable to development. The Pueblo Viejo gold mine is currently in operation in the Dominican Republic. It has become an important component of that country's economy. Pueblo Viejo output is important to the government as a foreign currency earner. It is also said to be among the world's more successful gold mines. But, while Pueblo Viejo is successful, no other major gold discoveries have been made in recent years. Therefore, alluvial deposits of gold have caught the attention of geologists on the Island of Hispaniola. In the past four years, exploration and investigation of alluvial deposits have been initiated in both the Dominican Republic and Haiti. This type of activity is expected to continue over the next few years. Alluvial gold mining is rudimentary gold washing, done mostly by farmers. It is an old tradition, dating back at least 100 years, and is done by small, independent, or community farming villages in the mountains and plains of the Dominican Republic. Investigations in the DR Recently, alluvial gold investigations have been undertaken in well known locations of the Dominican Republic. One is in the Villa Altagracia area. Here, the terraces and gravels of the Haina River basin were examined, test-pitted, and assayed by Minera Altagracia, a local Dominican mining group. Results led to a new investigation by the state-owned Rosario Dominicana (RD), the company that mines the gold at Pueblo Viejo. Rosario tested areas previously investigated by Minera Altagracia. RD could not define the type of concentration that could justify an industrial-scale type of exploitation. The Haina River placers are located in the flats and valleys of Central Dominican Republic. They are classified as small-scale type of operations where local cooperatives can do the traditional gold washing. It is not now considered a dredgable project for a mining company. The next alluvial gold investigation was undertaken by the Dominican Department of Mines and others in an area of some 700 km2 (270 sq miles) in the northeast near Miches. Farmers have been washing gold in streams and excavating pits in various areas, particularly La Mina and have made a living. Government geologists panned several hundred streams and river tributaries. They also washed material from deep excavations. The results, however, were negative insofar as locating alluvial gold concentrations suitable for large-scale or industrial-scale exploitation. The most favorable locations were the terraces along the Jayán and Cuarón Rivers in the area of Miches. But the grade od concentration is poor. Actually, only traces of gold were found in these

Jan 8, 1986

By D. Lenartowicz, K. R. Alexander, M Collings

Cosmo Howley is a gold deposit in the Northern Territory of Australia. The geology is complex and the input of geological data is an important part of the grade control process. As the geology of the deposit has become better understood, grade control and mining techniques have evolved to meet the changing circumstances. Present grade control depends on the use of angled blast holes, 21/2 benches and selective mining. Data is processed on site using 2 386 PC's running Surpac software. An environmental protection programme is employed, including soil stripping and stockpiling, sulphide waste containment and water quality monitoring.

Jan 1, 1989

By Mirian Mamani

El presente trabajo define nuevas zonas para la exploración del sur peruano a través de la identificación de fallas corticales y dominios geotectónicos, desarrollado por el Proyecto GR1: Geología de la Costa Sur y Vertiente Oeste de la Cordillera Occidental de la dirección de geología regional del INGEMMET. Los dominios están limitados por sistemas de fallas importantes y contienen Super Unidades intrusivas y Unidades volcánicas representativas , que permiten ubicar nuevos polígonos para la exploración de yacimientos minerales.

Sep 12, 2011

Don Hausen was a pioneer in the field of quantitative mineralogy. Methodology that he developed at Newmont almost 40 years ago is still employed today, only the technology has advanced. Petrographic methods were stressed with an emphasis on alteration, mineralisation and paragenesis. Methodologies employed by Don on the Carlin deposit were applied to developing the Carlin Trend by helping to work out lithology and structure, which ultimately led to the discovery of deep high-grade deposits. Quantitative methods used by Don on San Manuel, Copper Creek and Superior, Arizona were applied to the development of the Batu Hijau Deposit in Indonesia. Advancements in technology since DonÆs time have made the mineralogist much more efficient. Manual measurement of peak heights off of strip charts for semiquantitative XRD has been replaced by software that does Rietveld refinement and whole pattern fitting. Hand contouring of XRD data has been replaced by digitised data incorporated into geologic models. Optical point counting, which would take a dayÆs work to process 1000 points, has been replaced by automated SEM methods where 20 000 points are possible in an hour. The use of the optical microscope remains relatively unchanged, and still remains as Don emphasised the æeyesÆ of mineral exploration. However, the information can be relayed much more quickly with digital image capture and electronic data transfer. Don insisted on becoming involved in projects at the grassroots level and supporting the project through mine closure. This made the mineralogist a liaison between exploration geologists, mine geologists, metallurgists and mine engineers. The methodology that Don helped develop continues to provide invaluable support to Newmont geologists and metallurgists worldwide today.

Jan 1, 2008

By W. J. Miles

Industrial mineral by-products occur as a result of mining and processing a primary mineral product. By-products result from concentration and separation of accessory minerals during processing or from the primary mineral during processing, for example dusts. Many companies have found it rewarding to evaluate mineral by-products from their operations and determine potential products and applications. By-products need to be evaluated for physical and chemical properties to determine possible applications and markets. Market studies are needed to determine application specifications, price structure of the market, competitive products, and to determine marketing regions. The by-products need to be evaluated for beneficiation and processing to meet these market requirements.

Jan 1, 1985

By Peter B. Lilly

Thank you, Tom, I appreciate that generous introduction - and your generous welcome. When Doris Finnie asked me to speak here today, my decision to join you couldn't have been easier - for two reasons. First, I can't say no to an opportunity to return to Steamboat Springs. My family has wonderful memories of skiing here. And this time of year, golf in the mountains is so good you almost don't miss the skiing. The second reason this was such an easy decision is that The Rocky Mountain Coal Mining Institute is such an important forum for the coal industry, and it's certainly important to Peabody. We have mines in five western states - Arizona, Colorado, Montana, New Mexico and Wyoming. Last year, our western mines produced more than 110 million tons of coal. That's about two-thirds of our total domestic production. So western states are obviously critical to us. A couple of weeks ago, the west became even more significant to Peabody. Of course, I'm speaking of PacifiCorp's planned acquisition of The Energy Group - including Peabody - announced the middle of this month. Admittedly, when I agreed to speak here - some months ago - I had no idea just how much change Peabody would face in this relatively brief period. Still, not knowing then about the PacifiCorp announcement, I chose change as the subject for this talk. I'll update you on our recent news. But, first I want to establish a broad context for the PacifiCorp/Energy Group announcement and other change in the electricity business, change here in the United States and all over the world. ? We'll see how change is driven by two major trends - privatization in emerging markets and deregulation in mature markets, In turn, those two trends will cause ever-increasing consolidation - in both the coal industry and the broader power industry. ? After outlining those trends, I'll discuss the change that will dramatically affect Peabody following the announcement a week ago that PacifiCorp and The Energy Group intend to join forces to create one of the world's largest international integrated energy companies - an event that adds considerable credibility to the prophesies I'll outline in my remarks today. ? Finally, I will discuss an issue that threatens our industry's future - and, indeed, the economic future of all Americans. That issue is the inappropriate response to the unproven possibility of global climate change. Let's set the stage for change. And let's begin with the first trend I mentioned - the trend to privatization in developing economies. What drives the trend to privatization? Economics. It's all about the supply and demand of capital. And the engine that drives the supply/demand ratio is growth in electricity demand - tremendous growth in demand in developing economies. The U.S. EIA projects worldwide growth in electricity demand at 63 percent between 1990 and 2010, most of it in developing countries. This strong growth means that a new 500 MW power plant will be needed every three and one-half days until the year 2010. Now, if we say that a 500 MW plant will cost about $500 million dollars, we're talking about a bill of about $1 billion dollars a week - through 2010. That voracious demand for capital drives the trend to privatization. It means countries in Eastern Europe and the former Soviet Union want to sell generating assets. And Asian countries - for example, India, Indonesia and the Philippines - want to find private investors to build power plants. Privatization already is well underway. In the future, it will grow, with countries in South America, Central America, and Africa joining the trend. Bottom line: The privatization trend means rich new opportunities for companies willing to think beyond "business as usual." Meanwhile, developed economies face a different but no less fundamental change. Western European countries, the United States and Australia face deregulation. Why does deregulation represent such a big change? Consider a few basic facts about the U.S. electricity market to see what a big change -

Jan 1, 1997

By AIME AIME

EVEN in the choice of his birthplace and parents, Donald B. Gillies indicated clearly the trend of his professional career. He was born on Nov. 4, 1872, at Bruce Mines, in Ontario. His father and mother came from the Isle of Skye, Scotland, to Nova Scotia, moved from there to Canada, and finally settled in the copper country in the northern peninsula of Michigan, where the senior Mr. Gillies followed mining as an occupation. Donald's early education was in the public schools and he graduated from Linden Lake (Mich.) high school in 1890. Following the family interest in mining he entered the Michigan Mining School, now Michigan College of Mining and Technology. There he was the rare student who excelled both in athletics and scholastic work. On the athletic field he was a crack football player and track roan. As early as 1890 lie established a record of 10 sec-

Jan 1, 1938

Your assessment of the minerals business. The global mining industry is strong. I am convinced it will continue meeting the mineral needs of the world population for the foreseeable future. Two developments have greatly enhanced the industry’s ability to produce low-cost minerals. Technological innovations have resulted in increased productivity. And there has also been a dramatic expansion of the number of favorable countries in which to explore and mine. Capital expenditures have flowed to the low-production-cost mines and development projects as well as to the exploration projects and stable countries having the best potential for valuable mineral discoveries.

Jan 1, 2000

Curlisle: We're sitting in Don McLaughlin's office overlooking Sun Francisco Bay, and he's going to be good enough to talk about early days in California, maybe about his college years in Berkeley, maybe about his first jobs in mining. Now, Don, would you be good enough to start it off by saying something about George Hearst. I know he died before you were born, but you know a lot about the family, and you no doubt know a lot about him. Certainly, nobody in those days matched his record in getting hold of good mines. McLaughlin: George Hearst died, actually, in the very year that I was born, but as I more or less grew up in the home of Mrs. Phoebe Hearst, who was his widow, I heard a great deal about the mines and the people that made the great fortune she inherited and used so wisely. But I don't think I really had an appreciation of George Hearst until 1 became active in the mining world and realized how many major mines he had picked in the early days and how much he had to do with their development into successful properties. He started in the California gold fields, but it was on the Comstock that he made his first big stake out of his substantial share in the Ophir mine. I believe at that time he was on his own. Then, later, he became associated with Ben Ali Haggin and Lloyd Tevis in San Francisco, and scoured the West for them. They made a little money in Eureka, Nevada, and other places, but the first important property that he obtained for them was the famous Ontario Mine in Park City, which became one of the great silver lead producers of the Continent. Then later he acquired the Homestake.

Jan 6, 1965

By J. J. Gillman

"The coal deposits from Cape Perce on Cape Breton Island have been known to supply the coal requirements of the people living in or visiting the area for close to 300 years.A major block of coal has been identified off Cape Perce, which has several seams from which coal can be taken. The initial development by the Cape Breton Development Corporation will be in the Harbour Seam and constitutes the Donkin-Morien Development Project.The CBDC's confidence in this indicated resource is based on its knowledge of the Sydney Coal Field and from boreholes driven into the block during the summers of1977, 78 and 79. In 1980, further geological data were gathered from surface drilling and an intermediate-depth high-resolution seismic survey. The surface facilities for the Donkin-Morien Development Project will be located on the northern half of the cape, with access declines extending 3.9 km in a north-northeasterly direction to the Donkin block of coal reserves. The development has the potential of supplying all the coal needed f or the future electrical power generation requirements of Nova Scotia for many years to come.The planned mine, for which a project definition study has recently been completed, will have a production rate in excess of 3 million tonnes per year.IntroductionAt the Second CIM District 1 Meeting held in Halifax in October 1980, a background paper on Phase II of the Donkin-Morien Development Project was presented. The project involves a 3.2-million-tonne, saleable, underground coal mine. At that time, the chronological sequence of events had unfolded, starting with the initial boreholes through to the feasibility study, and on through site clearing and site preparation. This led to engineering design contracts for the portals and the two tunnels to be driven to intersect with the Harbour Seam close to 4 km from their entry point."

Jan 1, 1982

By Nicholas Chlumecky

One of the oldest mine supports in use today is timber cribbing. In many mining operations material, installation and maintenance costs for timber cribbings are substantial. Their performance characteristics also add to mining costs. During the 1970'6, the U.S. Bureau of Mines recognized many of the deficiencies of timber cribbing and very successfully initiated the development of steel-fiber- reinforced (SFR) concrete blocks. Since the early 1980's this SFR concrete cribbing has been manufactured as a high quality product which has found increasing acceptance by mine operators. The rapid acceptance of the SFR concrete block cribbing has proven that its use is eliminating many of the deficiencies of timber cribbing while providing superior load carrying capability. The use of SPR concrete blocks to build the cribbing is based on the same principle as wood. That is, stacking longitudinal, rectangular blocks in layers in a crisscross manner. The blocks are positioned at right angles to the blocks of the layer below. With this situation, the possibility of misalignment exists when the concrete blocks at the base are not placed exactly parallel or when the blocks of the base are subject to unequal settlement. Such misalignments creates localized, high stress areas which reduces the load capacity of the cribbing made from SFR concrete blocks. Recognizing the problem of misalignment, the Underground Supports Division of Commercial Shearing, Inc., conceived a circular, one-piece, steel-fiber-reinforced concrete cribbing which is being marketed under the name - Donut Cribbing. This concept eliminates the possibility of misalignment and provides 100% bearing between layers of stacked cribbing as well as other advantages. The purpose of this paper is to discuss the performance characteristics, installation speed and economical factors of each of the three cribbing types -- timber cribbing, SFR concrete block cribbing and SFR concrete Donut Cribbing.

Jan 1, 1986

By B. S. Spottiswoode

Lack of visibility makes it difficult for continuous miner (CM) operators to judge the desired sump depth. The resulting inaccuracies have proven to lead to significant production losses. This problem of measuring the depth of sump has been addressed in the past and a few measurement techniques have evolved. Despite various attempts, a suitable commercial depth of sump sensor does not yet exist. A system using the Doppler effect has been patented, developed and successfully tested. The method is non-intrusive and involves a beam of microwaves being projected obliquely at the roof. The received signal is analysed with respect to the transmitted signal, yielding the desired measure of displacement. Surface tests have revealed an accuracy of a few centimetres. Underground simulation tests on a load haulage dump (LHD) machine have verified the repeatability under the harsh conditions of interest. The system is presently being installed on a CM where it is to undergo a long-term performance evaluation. This paper presents the theory behind such a system, the hardware developed, the signal processing requirements and an analysis of the test results.

Sep 1, 2001

In 1985 a 2.5-tonne top blown rotary converter was installed in the silver refinery at Cominco's Trail Operation to carry out the final cupellation of burndown metal to Dore metal. The furnace is fired with an oxygen-natural gas lance which is capable of achieving a variety of furnace conditions, varying from reducing to highly oxidizing. Reaction rates are about 4 times greater than using conventional cupel furnaces. The faster reaction rates improve productivity and reduce in-process precious metal tie-up. The furnace is also used to reduce litharge slag for bismuth recovery.

Jan 1, 1989

By Kallioinen Jouko

"Advanced Flotation Technology is the application driven design of Don-Oliver flotation cells to achieve the optimum performance for each type and grind of flotation. Optimum performance is the combination of both recovery and selectivity.Optimized performance is the combined product of optimized mixing and effective froth removal. Optimized mixing is applied to roughers, scavengers, cleaners and specialty cells such as those to float hydrocyclone underflows in both primary and regrind circuits in order to reduce overgrinding. Effective mixing for fine material is easy, but overmixing reduces selectivity in frothbed.Selectivity in flotation is an important target, especially when treating complex ores, and parameters in frothbed have been examined to improve the separation of minerals and eliminate circumstances that reduce separation rate.Advances in process control have been achieved with expert controls and instructive operator information data. This has gained a higher degree of understanding of cell operation and ore type being processed to be used in future process development work. Excellent results of this Advanced Flotation Technology have been achieved and designs through 7000 cu ft (200 m3) are currently available for high capacity concentrators. This paper will detail how flotation cells are more responsive to the exact requirements of the duty specified."

Jan 1, 2000

By William O. Macha G

El presente trabajo describe la molienda y flotación como etapas de mejoramiento en la metalurgia del plomo en Paragasha. Para ello, se revisa los principales problemas de la metalurgia, como el de los minerales encontrados en la superficie, entre otros. Asimismo se describen los circuitos pertinentes de la planta piloto, como de la planta Paragasha y los resultados metalúrgicos en los meses de enero a marzo en 1965. En el primero, se señalan las dos etapas de molienda y flotación en el Pb, mientras que en el segundo, se muestra el circuito stándard: molienda y flotación.

Aug 20, 1965

Underground mechanized excavation in New Zealand has become more commonplace in civil and mining applications during the last three years. At one stage up to seven Dosco Road- header machines were being used on different projects around the country. The Huntly West Mine Drifts inclined at one in four were by far the most severe grade conditions that the machines were subjected to; however, other operations posed their own particular problems for the machines. Two major interrelated factors became evident as soon as the machines commenced at Huntly. These were traction problems on the grade and control of water, particularly on the invert.

Jan 1, 1978

By K. T. Audt

The Yayoi period, from about 300 B.C. to A.O. 300, represents a time of important changes in Japanese history. During this period the advanced rice culture of the Asian continent was introduced to Japan, along with the techniques of animal husbandry, spinning, bronze casting and metal working(1) . As was the case in the Jomon period (11000 B.C. to 300 B.C.), the Yayoi period is traditionally defined by a particular type of pottery, characterized by the use of the potter's wheel and an extreme simplicity of decoration and form(2) . Pieces of this pottery were found in 1884 in a district of Tokyo, known as Yayoi-Cho, not far from Tokyo University. Within a decade the name Yayoi had come to be used for the period which also saw the first casting of metals in Japan121. During the Yayoi period, the foundation of the ancient Japanese state was laid as the individual small communities were unified and as labour specialization and social levels developed. In fact, the Yayoi may be the true ancestral culture of Japan(3) . However, the origin of the Yayoi is not definitely known. One theory indicates that the Yayoi people may have been driven from the Asian mainland (via Korea) by the dynastic wars that accompanied the unification of China under the Ch'in and Han and that these settlers rapidly displaced the Jomon. Bronze objects and the cultivation of rice may have arrived about the same time - in the third century B.C. Iron was in Japan within another century, but since it rusts badly and disintegrates, only a few small pieces are known from such an early date(4) . After about 50 B.C., the Yayoi cultures of western Japan were in fairly close and regular contact with the continent via Korea(5)

Jan 1, 1999

By Rohan Stevens, Katsuhiro Kameyama, Osamu Iwata, Jinming Liao

In densely populated cities such as Hong Kong, where unoccupied space is becoming more valuable as the population grows, city planners are more often looking to underground space to meet the increasing need for transportation and services. Given the dense population of people, amenities and high-rise buildings above or near such underground space, it is essential to minimise any disturbance and potential damage during construction. Hence, the excavation of hard rock to develop such underground space can be highly restricted, expensive and time consuming. This is the case for many of the tunnels currently being excavated by drill and blast directly underneath Hong Kong’s busiest business districts and most popular residential areas.

Jan 1, 2013

By Utku Gumus, Ertan Bostanci, Hanifi Copur, Ahmet Rüfai Bilgin, Ugur Altay

"Field observations on replacements of 12-inch constant cross-section double disc cutters in Tuzla Wastewater Tunnel excavated by an EPB TBM with 3.151 mm excavation diameter excavating hard rock are summarized. Cutter life is correlated to rock’s uniaxial compressive strength and Cerchar abrasivity index, and TBM operational parameters. Number of cutter replacements, average cutter replacement rates and types of cutter damages are summarized. The relationships between cutter life and rock properties and TBM operational parameters are analyzed by single variable regression method. Detailed analysis between chainages 1+200 and 1+982 km indicates that average cutter consumption rate is 35.7 m3/replacement (4.6 m/replacement). Cerchar abrasivity index and uniaxial compressive strength does not indicate any meaningful relationship with cutter life. Penetration per revolution and field specific energy might be used for predicting lives of constant cross-section double disc cutters. However, additional data is required to generalize the findings of this study. INTRODUCTION Cutter life / replacement and/or consumption rates in terms of cutter cost and replacement time loses is one of the most important parameters affecting excavation performance of mechanical excavators, especially of TBMs used very widely and equipped with usually disc cutters. Predicting cutter cost is a very important task in especially feasibility stage of tunneling projects. Basic parameters affecting cutter life can be classified into 3 general groups as geological and geotechnical, excavation machine (TBM) related, and operational parameters (Bilgin et al., 2013). The geological and geotechnical parameters are the most dominant ones among them. The machine related parameters should be arranged in accordance with the expected geological and geotechnical conditions for the best TBM excavation performance and minimum cost."

Jan 1, 2016

By Edward T. Koch

With the dramatic increase in world demand for basic raw materials, open pit mining is proceeding at an unprecedented rate. A viable demand is the ever tempting Siren's song for increased production or new facilities. When the Siren's lure is viewed against the panorama of today's world economic milieu the concomitant Scylla and Charybdis are seen in the form of high capital cost and high operating cost. If the economic realities of present day open pit mining are to show a proper return on investment, a clear and penetrating eye must be cast upon the area of mine planning. This paper deals with the problem of overburden removal. In almost every open pit mining operation overburden removal is a significant part of the capital cost and operating cost of the total operation. This paper deals with a new and unique method to affect economical overburden removal. Well known to all are the parameters surrounding draglines, shovels, and bucket wheel excavators. All of these machines require a reasonably stable soil to support them and the shovel and bucket wheel excavator require a reasonably stable bank in which to operate. Their reliability, portability and rate of production per dollar of invested capital are good.

Jan 1, 1975