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By M. Botz

Anatolia Minerals Development Limited (AMDL) is constructing the Çöpler Gold Project in eastern Turkey and commenced mining in the fourth quarter of 2009 with gold production scheduled to begin in the fourth quarter of 2010. The project is a 15,500 tonnes/day oxide heap leach with three-stage crushing, agglomeration, carbon adsorption and electrowinning for final metal recovery. Leach solution copper levels are expected to be relatively low during the first two years of production but will increase in later years due to higher copper content in the mined and processed ore. Over the mine life approximately 40 million tones of ore will be placed on the leach pad, which will contain about 35,000 tonnes of copper. Metallurgical testing indicates copper extraction will vary by ore type and, if controls are not implemented, may lead to copper levels exceeding 1,000 mg/L in pregnant solution. High copper levels in leach solution have the deleterious effect of increasing cyanide consumption and potentially overwhelming the ability of the carbon circuit to effectively adsorb the principal economic metals, which in this case are gold and silver. Using data obtained from laboratory leach column testwork, the heap leach facility was modeled using METSIM process simulation software to estimate the build-up of copper in leach solution over the mine life. Laboratory testwork was also performed to evaluate process conditions for treating a portion of pregnant leach solution via sulfide addition to precipitate saleable copper as copper sulfide (Cu2S).

Jan 1, 2011

By C. N. Logan

The Southern Company is one of the nation's largest electric utilities and is the parent firm of five operating companies: Alabama Power, Georgia Power, Gulf Power, Mississippi Power and Savannah Electric and Power. Another subsidiary is Southern Company Services (SCS) which provides engineering and technical sup-port to the five operating companies. This technical support includes the procurement and supply of over 40.9 Mt (45 million st) of coal annually for the 22 coal fired plants in the system. Approximately 80 percent of this tonnage is purchased under long term contracts and the remaining 20 percent is purchased on the spot market. The coal is principally supplied from Alabama, Illinois Basin and the eastern Appalachian coal fields. Most of the coal is delivered by unit train and barge but one plant in Alabama receives all its coal by truck and conveyor belt.

Jan 1, 1990

By K. Oraee

Proven and probable coal reserves in Iran are estimated to be in excess of 5 Billion tons while the annual coal production is a mere 2 Million tons. Underdevelopment of the industry has proved higher production levels to be impossible, despite growing demand for energy supplies. The existences of numerous legislation are thought to have a detrimental effect on coal mining activities to the extent that some business entities have become uneconomical in many areas. This paper provides an analysis of the prevailing mining laws, policy making, legal frameworks and obstacles. It also outlines some other obstacles enshrined in the law and also highlights areas where foreign direct investment should be encouraged. The costs of lost opportunities are then estimated. The paper concludes by demonstrating that deregulations, amendments and in some cases complete abolishment of the incumbent legislations governing the coal mining industry will greatly enhance development of the industry. The analysis provided in this paper together with the results obtained, can prove useful to macro-economic policy makers both at local and national levels.

Feb 27, 2013

By Byron T. Darnton

Gravity concentration at the Pegasus Gold/Montana Tunnels Mine, near Helena, MT, began in June 1991 when a coarse-gold-scalping circuit was commissioned. It processes a small portion of the ball-mill circulating load to reduce the risk of gold particles that are too coarse to float from advancing to flotation. The circuit also cost-effectively enhances overall gold recovery and payable gold ounces. This gravity circuit has been a major success. Since the circuit was commissioned, throughput has increased 30%. Several modifications and improvements were made during the last three years that allowed the gravity circuit to keep pace with the higher tonnage. The overall approach to gravity concentration at Montana Tunnels has always been to optimize production rather than maximize the gold ounces produced. This philosophy has now yielded a circuit expansion and relocation project. It will allow for an estimated 50% increase in gravity gold production, while significantly reducing the unit costs of production.

Jan 1, 1995

By W. C. Brice

A cooperative study was undertaken by representatives of the environmental community, the mining industry, and state government to identify and resolve environmental issues associated with base and precious metal mining in a neutral atmosphere before a commercial mining development is announced. The study included testing Minnesota's as-yet-untried non-ferrous mining regulatory program using three hypothetical mining developments sited in environ-mentally sensitive areas where future mining could occur. Results include identification of critical paths for regulatory decision making, identification of particularly sensitive environ-mental issues that will need continued deliberation before resolution, and characterization of data necessary for environmental review and permitting decisions.

Jan 1, 1990

By J. Gentry

Chemical grouting has been successfully used for over forty years to control the movement of groundwater in a wide variety of applications including tunnels, subway systems, sanitary sewers, mines and construction projects. This paper illustrates the versatility of chemical grouts by reviewing three projects where chemical grout was utilized to address some very difficult water control challenges. The featured product is acrylamide which can be used alone or in conjunction with other types of grout such as cementitious products. Acrylamide grout is injected as a two component product that will react and form an impermeable gel when the components combine. There are notable differences between the acrylamide based products and cementitious products. The most notable and significant difference is that acrylamide is a true solution grout that contains no particulates and has a viscosity of 1-2cps. This feature enables the acrylamide grout to penetrate very small geological features that other grouts could not penetrate and to seal small cracks and fissures where groundwater seepage is occurring. The product also has an adjustable gel set time from a few seconds to several hours which enables the operator to determine the product travel before it forms a gel. When properly applied the product has a half-life in the soil of 362 years (per testing by the US Department of Energy).

Feb 27, 2013

By C. Green, J. Uhrie, C. Filippone, A. Guzman

A central aspect of heap leach management and recovery optimization is solution control. Insofar as each heap is unique in physical and metallurgical properties, it is essential to understand the hydraulic parameters that control the migration of solution on a case-by-case basis. Water Management Consultants, as part of an ongoing research effort for Phelps Dodge Process Technology Center, have adapted techniques of parameter estimation for application to data typically resulting from metallurgical column testing. The parameterization is completed within the context of a variably saturated flow model that allows interpretation of available hydraulic information collected during hydrometallurgical column tests. A novel interpretation approach is introduced to extract the necessary hydrodynamic parameters from typical hydrometallurgical data sets. Results from the application of the approach to standard metallurgical test data will be presented together with a discussion of the application of information gained to the design and operation of a heap.

Jan 1, 2002

By R. Bokotko, J. D. Miller, J. Hupka

Laboratory results from an initial study on the removal of SO2 from gas mixtures are reported using air-sparged hydrocyclone (ASH) technology. Tap water and alkaline solutions were used for absorption and the influence of gas flow rate, water flow rate and length of the ASH unit were investigated. Complete removal of SO2 was possible with very favorable kinetics. The efficiency of sulfur dioxide absorption from air using the ASH is compared with the efficiency of conventional technology.

Jan 1, 2002

By B. A. Slaker

The ability to detect and quantify ground movements in underground mine workings is of the utmost importance to the safety of miners and continuity of operations. Rib sloughage is one of the most common forms of underground deformation. Remote sensing techniques, such as laser scanning, can be used to quantify this rib sloughage, by recording precise, timelapse point clouds of mine workings. In order to determine sloughage volumes and locations, two sets of laser scans were performed 42 days apart at a working section of an underground limestone mine. During this period, significant sloughing and scaling occurred, allowing for differentiation between the initial and final point clouds. Volumetric changes of 2.3-2.6 m3 were detected on rib faces during the time-lapse study. In addition, displacement in the mine roof was, as expected, not detected, suggesting well surveyed scans and an appropriate scan resolution.

Nov 1, 2013

By Simon D. Strauss

This article is part of a presentation Strauss made Dec. 3, 1988 at the sixth annual American Mining Hall of Fame (AMHofF) banquet in Tucson, AZ. At the banquet, the Mining Club of the Southwest honored Strauss by naming him the 1988 recipient to the AMHofF. (Industry newswatch, page 6). Introduction In the last two decades, there have been two previous periods of sharply rising copper prices. One was in 1973-74; the other in 1979-80. In both cases, a short period of high copper prices was followed by steep and prolonged periods of low prices. In the language of the market analyst, the high prices were called spikes. Is it likely, then, that three or four years from now the present price of copper will show up as a spike in the charts? There are substantial differences between the current position and the markets of 1973-74 and 1979-80. In 1973-74, US copper prices were subject to government-imposed price ceilings of $0.60 per lb through early December, 1973. These were increased to $0.68 per lb through May, 1974. Meanwhile, mines outside the United States were free of restraint. Rising demand in London pushed the price above $1 per lb in the third quarter of 1973. In early April 1974, it reached a peak of $1.50 a lb. In May of that year, the US ceilings were removed and the domestic price began to rise. What were the causes of this price strength? While ceilings held the domestic price below the world market, domestic consumers acquired all the tonnage offered by US mines. Meanwhile, in the world market, buyers feared prolonged shortages. The Club of Rome had warned that world economic growth would be limited by impending depletion of mineral resources. There was al so concern about a copper cartel that might increase copper prices even more. In early 1974, at a special United Nations session, developing-country spokesmen warned the industrialized world to expect high commodity prices. Also adding to the concerns of copper buyers was the fear that when US wage contracts expired in mid-1974, protracted strikes might ensue. The combined effect of this atmosphere was that consumers accumulated large amounts of copper, far above their normal carry. By midsummer, the position changed radically. While some strikes did occur in the United States, they proved short-lived. The most significant development was a massive economic recession. The energy crisis was causing enormous dislocations in the world economy. Construction activities were sharply reduced and automobile sales plummeted. Public confidence was shaken. Copper sales fell precipitately as consumers decided to draw down their swollen inventories. The price came down too. In April 1974, the London price- as noted-was $1.50 per lb. By the end of the year, it was down to $0.57 per lb. In 1973-74, the copper price rise was fed by fears of shortages, cartels, and strikes. In 1979-80, the market rose on the strength of good demand plus political and military instability. The price rise was also fed by inflationary trends, exemplified by speculation in precious metals. Prior to this second spike in copper prices, the market had been depressed despite economic recovery. Despite reduced US output, copper production in the rest of the world was increasing. Though consumption was rising, surplus stocks reached unprecedented levels. At the end of 1977, the aggregate of stocks at the refineries and in the exchange warehouses was 1.5 Mt (1.67 million st). That was more than three months' shipments at then rates of consumption. In 1978, the statistical position improved. Shipments of refined copper that year were 8% greater than in 1977. The result was reduced visible stocks but -just as was to be the case in 1984-86 - the price remained depressed. In 1979, an even sharper drop in visible stocks occurred as shipments rose by another 4%. This time, though, the price responded. In December 1978, the price in current dollars had been less than $0.70 per lb. By the end of 1979, it was above $1 per lb. And in the first quarter of 1980, it averaged more than $1.20 per lb. Military and political developments were a factor. The hostage crisis in Iran was followed by the Soviet invasion of Afghanistan. To many, it appeared that war might result if the Soviets pushed on into Pakistan. At the same time, speculation drove gold and silver prices to incredible levels. As silver prices rose above $40 per oz), copper above $1 per lb did not seem unreasonable. Then, in March 1980, the precious metals price boom collapsed. Copper prices also retreated, though not as much. In February 1980, the copperprice averaged $1.32 per lb. By December, it had dropped to $0.85 per lb. In 1981 and 1982, the decline continued. The present copper situation Why is the current situation different from these two previous episodes of high prices? First of all, today's inventories are far lower than they were in either 1974 or 1980, when the price declines began. The stocks at refineries and in exchange warehouses are substantially less than they were then. More significantly, consumers today have very limited holdings compared with stocks they carried in 1974 and 1980. Even if faced with a downturn in their own business, copper consumers will not be able to stay out of the market. To the extent they have any business at all, they will have to buy copper. And on the supply side, there is also a significant difference. The year 1988 has been unusual. US production is up sharply, responding to higher prices. But production is little changed in the rest of the Free World. Indeed, several of the major producing countries have mined less copper this year than in 1987 despite the prices increases. Peru has had labor problems that have cut its output. Zambia and Zaire suffer from shortages of expatriate technicians, not to mention spare parts. They also suffer from the failure to maintain equipment or perform adequate development. In Chile, the two largest mines, Chuquicamata and El Teniente, have not met their production targets. Chuquicamata is struggling with high arsenic content in its ore. And, in late 1987, severe rockbursts hampered operations at El Teniente. In addition, depletion of some mines in Australia and South Africa has offset rising output at other properties. Indeed, when final mine output figures for 1988 become available, it may well be

Jan 1, 1989

Most statistical and geostatistical methods of re-source and reserve estimation work extremely well for Normal (Gaussian) well-behaved information. However, most interesting mineral deposits exhibit far from this idealistic distribution of values. It seems that the more valuable the mineral, the less likely the data are to have a Normal distribution. Values tend to be "positively skewed" with a long tail into the high values. Using averaging techniques, such as inverse distance or ordinary kriging may result in consider-able overestimation of grades and tonnages unless such values are cut or otherwise modified. This paper presents some real case studies where distributions are (a) highly skewed and (b) the product of multiple phases of mineralisation. Practical methods are presented for solving such problems including combinations of indicator and log normal kriging methods. The emphasis of the presentation is on developing operational methods which can be used on project evaluation or grade control in producing mines.

Jan 1, 2000

Seven legendary figures of American mining will be enshrined in the National Mining Hall of Fame in ceremonies on Saturday, Sept. 7 at the Little America Hotel in Salt Lake City, UT. The 15th annual induction banquet will begin with a reception at 6 pm, followed at 7 pm by the dinner and the program. Of the seven inductees, one is living. He is Alexander Murray (Bud) Wilson, 80, of Los Altos, CA. Wilson led Utah Construction (later Utah International) to become one of the world’s most diversified and successful mining companies in the 1960s and 1970s. It was acquired by General Electric in 1976.

Jan 1, 2002

By Andrew Finney

INTRODUCTION The Sacramento Regional County Sanitation District (SRCSD) serves unincorporated areas of Sacramento County, parts of the cities of Sacramento and Folsom, and the cities of Citrus Heights, West Sacramento, Rancho Cordova, and Elk Grove. SRCSD maintains 145 kilometers (km) (90 miles) of interceptors that convey a combined total of 0.6 million meters3 per day (160 million gallons per day) or more of waste-water, with additional miles of sewer interceptors that are scheduled to be built by 2020. Wastewater is conveyed to the Sacramento Regional Wastewater Treatment Plant in the southwestern portion of the County, also managed and operated by SRCSD, in interceptors with diameters as large as 3.0 m (120 inches.) As part of its overall expansion program, SRCSD has constructed a number of major interceptors over the last few years with tunneling methods due to concerns associated with either the impacts of open cut construction in an urban environment (traffic, safety, noise, environmental concerns) or the need to achieve a crossing of a stream, river, or transportation corridor. This paper focuses on a specific issue that affected construction of the Upper Northwest Interceptor (UNWI) Sections 3&4 project, located at the northern limit of the SRCSD service boundary and within the limits of the City of Sacramento. This project involved the construction of 3.2 km (2 miles) of 2.1-meter (84-inch) and 2.4 km (1.5 miles) of 1.7-meter (66-inch) diameter reinforced concrete pipe (RCP) using MTBM, EPBM, and 3.3-meter (130-inch) two-pass TBM methods. The owner elected to install the RCP using tunneling for a number of reasons including a desire to avoid traffic impacts in a dense urban corridor, to minimize disturbance to the neighborhood, and to avoid potential dewatering-induced settlement issues along the western one-third of the project. For the western portion of the alignment the 2.1-meter (84-inch) reinforced concrete interceptor pipe was to be installed using a 2.7-meter (105-inch) earth pressure balance machine (EPBM). No external dewatering of shafts or tunnels was permitted for reasons of concern about settlement, discussed previously. At the intersection of Elkhorn Boulevard and Natomas Boulevard (at the extreme northwest corner of the project) the 2.7-meter (105-inch) EPBM tunneled past a recently constructed 11-million liter (3-million gallon) water storage reservoir, passing within 3 meters (10 feet) of the tank?s shallow foundation while tunneling through clean sands with a shallow groundwater table. The paper will discuss the implemented solution to mitigate additional settlement risk that was developed as a joint collaboration between the owner, CM, designer, and contractor.

By Dan Witkowsky

For the 36th consecutive summer, the Colorado Mining Association Education Foundation and the Colorado School of Mines have sponsored “A Total Concept of the Mining Industry” for kindergarten through grade 12 teachers. Teachers from 34 states, plus the District of Columbia and two foreign countries, have graduated from the four-week course. They received six hours of recertification credit. This summer 31 teachers from Colorado, Kentucky, Virginia and Alaska completed the program. The course is unique from other shorter courses in that it solicits teachers of all disciplines from all K-12classes. In addition to the expected earth science and mathematics teachers, the Class of 2004 consisted of educators who teach music, chemistry, biology, social studies, history, basic English and world history. Others in the program included those who teach American history, physical and life science, remedial reading, consumer/family studies, “world of work,” language arts, engineering technology, environmental science, world geography, human anatomy and physiology, and business.

Jan 1, 2004

By Pan Gao, Songyang Yin, Zhibiao Guo, Jinglin You, Yuhui Li

Under the geological conditions of the interaction of upper goafs and lower working face in deep mining, coal seam mining causes a large stress concentration, which may lead to large deformation of the surrounding rock and rock burst risk. The research reported herein is aimed to utilize the FLAC3D software to establish a three-dimensional numerical model and analyze the law of the surrounding rock stress evolution during coal mining under complex geological conditions. The simulation results reveal that the peak abutment stress reaches its maximum value at 20–30 m in front of the working face, about 1.8–4.3 times the original rock stress, and the peak stress is larger in the stable mining stage. Along the dip of the working face, the peak stress occurs about 8–10 m away from the roadway side. The upper barrier coal pillar and the interval coal pillar in order exhibit stress concentration areas of 142 m and 88 m. According to the law of the deflection stress distribution of the surrounding rock in the presence of various widths of the coal pillar, a 10-m coal pillar between the roadway and the adjacent goaf could enhance the stability of the roadway. For the stress concentration area, drilling holes with a depth of 20–25 m are utilized to reduce the pressure, and anti-impact supports are installed in the middle of the roadway. Due to the varying stresses of the rocks around the roadway, partition prevention and control countermeasures are capable of efficiently preventing the instability of the surrounding rock.

Mar 22, 2023

By Robert M. Matyas, P. E. Sperry, Robert J. Smith, A. A. Mathews

INTRODUCTION The first Dispute Review Board (DRB) was utilized on a tunnel project 20 years ago. Increasingly utilized on a wide range of construction projects, DRB's are becoming the norm on tunnel and underground projects. This paper summarizes the growth in this usage, uses observations and experience to establish that barriers to the utilization of DRB's are more perceived than real and that many arguments against the DRB concept are not valid, and notes some of the salient elements that should be considered in practice to optimize DRB effectiveness. The purpose of the paper is to provide an annotated checklist for current and prospective users. The basic concept, structure, and operation of DRB's are described elsewhere and will not be repeated here (ASCE, 1991). DISPUTE REVIEW BOARD USAGE A compilation of Dispute Review Board usage for tunnel and underground projects to January 1994 indicated use on 63 contracts with a cumulative construction value of $3.8 billion and a total of 60 disputes settled. As of that same date, DRB's were planned for another 63 contracts with an estimated construction value of $4.7 billion. (A listing of these 126 projects is available from the authors.) This success and popularity have spread to other civil projects as well as process and building construction. The increase in DRB usage has been exponential. See Figure 1.

Jan 1, 1995

By H. Michael Breza

Texasgulf Inc. installed bucketwheel excavators and overland conveyor sysems at its Aurora, NC phosphate mine o increase the productivity and flexibilty of the surface mining operation. This ;ystem has significantly improved overrall. Its flexibility is evidenced by adapation to operation requirements, such is mining area moves, movement of xcavated overburden to designated ites, selective handling of overburden, poll placement contouring, and proiding an environmentally sound and afe operation. The system's productiv:y is evidenced by case studies relating. overall production, excavation rates nd cost-effectiveness. There are many competing alternaves available for excavating uncon)lidated overburden: truck-shovel, raglines, dredges and bucket wheel ticavators. These alternatives also may used in tandem to recover reserves icated at greater depths.

Jan 1, 1993

By Xuehui Li, Xinshuai Shi, Jun Wang, Jianguo Ning, Shang Yang, Zhaohui Zhang

Pressure relief is an important step in preventing and controlling rock burst disasters. Hydraulic slotting has emerged as a strategy for pressure relief and energy release in roadway surrounding rock. There is no qualitative description for the response relationship between hydraulic slotting parameters and the degree of pressure and energy release in a roadway, which is a scientific problem. In this paper, theoretical analysis, numerical simulation, and on-site industrial practice were comprehensively used. First, a structural model for the pressure relief and energy release of coal by hydraulic slotting in a deep roadway was established, and the pressure relief and energy release principle by hydraulic slotting was revealed. The principles and methods for determining hydraulic slotting parameters in the roadway were proposed. Three evaluation indices for the pressure relief and energy release effect of coal after hydraulic slotting were proposed, namely, the stress ratio of coal, elastic energy density ratio of coal, and displacement rate of the roadway rib. According to the evaluation indices, the degree of pressure relief and energy release was divided into three levels: reverse pressurization, full pressure relief, and transitional pressure relief. Then, a FLAC3D numerical model was constructed, the levels of pressure relief and energy release under different hydraulic slotting parameters were analyzed, and the optimal slotting parameters were determined. Finally, on-site industrial practices were carried out in Panel 7312 of the Xinhe Coal Mine. An effect test showed that the effect of pressure relief and energy release was remarkable after hydraulic slotting was adopted on the roadway surrounding rock, which can effectively reduce the risk of rock bursts. These research results can further improve hydraulic slotting technology systems and provide a theoretical basis and technical reference for the stability control of deep roadway surrounding rock.

Sep 20, 2023

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept.9, 2006 at the Museum Convention Center in Leadville, CO. The four inductees are Earl H. Beistline (1916 to present), R.A.F. Penrose (1863-1931), Robert M. Reininger (1912-2006) and John Stanton (1830-1906). The inductions will bring to 193 the number of mining “greats” whose engraved photographs and biographical sketches are installed in the National Mining Hall of Fame.

Jan 1, 2006

By D. Tao

The reverse cationic flotation is the most widely utilized flotation method for concentrating iron ore. In such a process quartz is often floated with ether amines (R?O(CH2)3?NH2) partially neutralized with acetic acid. However, it is well known that the cationic flotation of hematite does not work well if a certain amount of slime is present in ore slurry. To improve flotation performance, starch is often added to the flotation feed to selectively flocculate and depress the iron minerals and sodium silicate is used to disperse the silica gangue. The present study was conducted to improve the flotation efficiency of iron ore flotation by use of a new type of depressant for clay and iron minerals, i.e., GP clay binder. It is postulated that the GP clay binder minimizes slime adsorption on quartz and hematite particles by agglomerating clay particles to reduce their surface area. It is further theorized that the clay binder helps depress hematite flotation due to its unique chelating ability to iron ion. The results from this study clearly show that the GP clay binder is an effective depressant in iron ore flotation. When it was used as a substitute for corn starch, it increased concentrate grade from 60.78% to 67.67% and increased iron recovery from 71.96% to 72.90%. The combined use of GP clay binder with corn starch produced even better flotation performance, increasing concentrate grade to 67.08% and iron recovery to 78.15% simultaneously. Key words: Clay Binder; Depressant; Iron Ore; Flotation.

Jan 1, 2009