Search Documents

By J. P. H. Steele, M. U. Ozbay

As mining operations progress toward tele-mining and autonomous procedures, the need for machine performance monitoring increases. Presently, through a combination of vision, sound, and other subjective observations, an operator attempts to optimize the mechanical excavator’s operation. As the operator is moved away from the face in the case of tele-mining or completely removed for autonomous operation, the qualitative sensory input is lost. This lost information must be replaced with quantifiable sensory input. Chip formation detection may be a suitable replacement sensory input. Chip formation can be predicted with high confidence (>80%) through the analysis of the load waveform associated with the bit/rock interface.

Jan 1, 2002

By T. Martinez Patino

Precious metals have been sought by man through time. The search has been the cause of many historic events as well as the founding of the famous Mexican, Minion centers of Durango, Guanajuato, Zacatecas and others. Bacis, a silver - cold deposit in the State of Durango was one of the lesser known centers established during Spanish colonial times. During the past year, metal prices have suffered a substantial decline, resulting in the closure of many mines. Through astute exploration, development and exploitation of the mine, the effect of the low prices has been offset and the mine is surviving these hard times.

Jan 1, 1994

By Jukka Pukkila, Pekka Särkkä

Intensive co-operation between mining industry and mining machine manufacturers during an eight year program Intelligent Mine™ led to a new concept for applying automation technology in mining to improve the productivity and safety of mines. 'The results of the program are now implemented in several mines in Finland and with similar ideas as well elsewhere in the world. The degree of optimal automation of an intelligent mine depends on several technical and economical factors. The basic precondition for the approach is a clear improvement in total economy of the mine.

Jan 1, 2002

By G Luxbacher

Computer simulation of mine ventilation systems is rapidly becoming an essential tool in mine planning and design. This paper examines the utilization of ventilation simulation techniques to evaluate the number, shape, size and layout of mine entries in a typical coal mining system. Since the mains and sub-mains serve mainly for transportation and ventilation and the ventilation system is critically important to the health and safety of the workers, there exists a great need for optimal designs in this area. Evaluation criteria, could include, among others, minimization of power costs, shaft requirements and leakage. Constraints of this optimization problem include health and safety regulations and production and mine infrastructure requirements.

Jan 1, 1977

"?irovski Vrh" Uranium deposit in Slovenia is type of mineralized sediments in ore bearing belts of deflected S-structure, in which the belt is less than 25% mineralized. Ore bodies of irregular small thickness, unreliably contoured, made difficult estimation of correct contours, which are necessary for design and exploitation works. The deposit was explored by vertical boreholes made at the surface and by boreholes fanned from drives. For the purpose of application of this estimation method, 1 m composites have been made in slices which were parallel to the referential belt plane. Estimation was made for 1,5m x 1,5m x lm blocks which do correspond to the size of the containers in the ore transport stage. Two variables have been used: the first, indicator of function (ore=1, waste material =0) and kriging method; the second, logarithmical content of Uranium and Minimum Mean Square Error Estimation (MMSEE) method. Based on estimated values of those variables, probability of ore quantity as well as Uranium content over determined cut-off were calculated for each block. Those two parameters enable determination of the most probable form of the ore body in ecah one metter slice. Estimation of sixteen small blocks in a large 1,5m x 1,5m x 1m block made possible estimation of ore quantity and its content for the determined cut-off, as well as categorization of exploration. This method is being used for estimation of ore reserves and planning of exploration operations. The described' methodology was tested in an exploitation block.

Jan 1, 1986

By S. R. Clark

"INTRODUCTION Of all the natural resources being taxed by the needs of the modern world, perhaps the most important is the continually expanding demand for water resources. As water becomes scarcer, and increasingly important, new technologies are needed to find innovative ways to preserve this precious resource. In Chile, for example, the mining industry is investing billions of dollars to build desalination plants and pipelines; bringing ocean water as far as 200 kilometers inland to meet their demand and maintain operations. It is a full-blown crisis for that nation and a top priority for their government and economy. It has been reported that world water consumption will increase by 40 percent in the next 10 years, representing nearly exponential growth. In the U.S., as more and more communities continue to be built, more drain on the current water infrastructure is created. For 25 percent of people and operations that rely on water from aquifers, this source is being consumed at a rate that will create significant problems meeting the demand in as few as two generations.1 A PROACTIVE APPROACH When it comes to controlling dust at your operation, whether a landfill, a transfer station, a haul road or another ancillary area, what are the options? We know watering is not the answer, but at the same time, we need to prevent dust from flying to ensure a safe environment and keep our skies clear of pollution, for both regulatory requirements and neighbors. Creating a Dust Mitigation Program instead of looking to buy the first dust control product off the shelf is a first step to conserve water and, at the same time, maintain the operational demands and environmental standards for a given site. The program concept is straightforward enough. However, the process of effectively constructing and executing a program is quite involved. When undertaking a program, each manager needs to work with their team and their partners/vendors in analyzing the following elements: 1. Site Expectations—It is important to understand how to balance your internal standards with your regulatory requirements, as well as how to keep your neighbors satisfied. 2. Site Aggregate—Variations in native soil, such as clay content or gravel levels, greatly affect the approach that will yield the highest results. 3. Climate—Relative humidity and seasonal variations are critical to achieving predictable results through product choice, application frequency and timing. 4. Daily Traffic—The type and frequency of traffic is an essential variable for site management. 5. Environmental Responsibilities—If you have additional, specifically defined responsibilities, the approach to your site may vary. 6. Budget—While efficiency is the goal of any program, some sites will have more stringent restrictions than others. 7. Current Usage Rates—Document and understand where you’re starting from, both with water, supporting products, and maintenance so that effective measurement of results is possible."

Jan 1, 2018

By E. Simoncini, S. Ulgiati, M. Raugei

A thorough Life Cycle Assessment of ilmenite extraction and processing to yield synthetic rutile (ERMS/EARS process) was performed according to ISO norms 14040 and updates. The LCA includes the parallel application of selected environmental impact assessment methods (as illustrated in Ulgiati et al. [1]), the results of which are compared and discussed. A MI value of 16 kg of abiotic matter per kg of output rutile is calculated, which is largely determined by the amount of coal that is employed in the reduction and drying steps. The Gross Energy Requirement is 3.33 * 107 MJ/kg, a value which we found to be comparable with that previously calculated by us for alumina. Finally, the increase factor of the Emergy Intensity from the raw mineral to the marketed rutile is 3.19, which points to a comparatively medium-low requirement for indirect environmental support. GWP and AP were calculated to be respectively 1.89 kg(CO2eq)/kg and 12.7 g(SO2eq)/kg.

Jan 1, 2005

By F. D. Mendes, A. H. Martins

The high copper grade in the Igarapé Bahia (Brazil) gold-copper ore restricts the direct application of the classical cyanidation process. Copper oxide and sulfide minerals react with cyanides in solution, causing high leach-reagent consumption, raising processing costs and decreasing gold recovery. According to studies, a feasible solution would be to pretreat the ore to remove copper minerals prior to cyanidation. The goal of this experimental work was to study the conditions for the removal of copper from the Igarapé Bahia gold-copper ore by sulfuric acid leaching, applying a statistical approach to the experimental design. By using the Plackett Burman method, it was possible to select the variables that exhibited the largest influence on copper extraction at the sulfuric acid leaching stage. These variables were leach solution temperature, stirring speed, sulfuric acid concentration in the leach solution and ore particle size. The individual effect of these variables and their interaction influences on the experimental response were analyzed by applying the replicated full-factorial design method. Finally, the selected variables were optimized by the ascending-path statistical method, which determined the best leach experimental conditions for maximum copper extraction. The optimized leaching conditions resulted in a copper extraction of 75.5%. Keywords: Copper, Gold, Extraction, Sulfuric leaching, Optimization

Jan 1, 2003

By Wayne A. McCurdy

I welcome the opportunity to meet with you and discuss the work and program of the Office of Coal Research. Our programs are oriented to serve the conservation objectives of the Johnson Administration and of the Nation by seeking out the most efficient and best uses for coal. We believe that even if only a portion of our program is successful, the coal industry and the Nation will benefit far out of proportion to our expenditures. Operating with a budget of $7,220,000 in Fiscal Year 1966, OCR sponsors contract research which offers potential for achieving benefits to the coal industry in the form of new production and new markets. This directs us into many areas of research activity: in coal combustion, in advancements in mining methods and coal preparation, in new uses for coal, and in associated economic and marketing research.

Jan 1, 1966

By Christopher E. Dianora, Matthew Sorrell, Eileen Test

"Constructed between 1939 and 1945, the Rondout-West Branch Tunnel (RWBT) portion of the Delaware Aqueduct is 45 miles (72 km) long. The New York City Department of Environmental Protection (NYCDEP) first identified suspected areas of leakage from the RWBT in the 1990s. A $1 billion project is underway to mitigate the leakage through the construction of a bypass tunnel around the area of most severe deterioration, a 2.5-mile (4 km) section located beneath the Hudson River. Two shafts, 800 and 900 feet (244 and 274 m) below the ground surface, are being sunk to support the tunnel construction. The deep shafts will be subjected to high groundwater pressures and have been designed to accommodate multiple tunnel portals. This paper discusses the engineering decisions and analyses leading up to the final design. INTRODUCTION Project Background The New York City Department of Environmental Protection (NYCDEP) provides over 1 billion gallons (3.7 billion liters) of water to over 9 million residents of the City of New York and surrounding communities each day. This water is stored in upstate reservoirs and conveyed to the City via a system of aqueducts and tunnels. Water is delivered to the City almost completely by gravity and consists of three systems: the Croton, the Catskill, and the Delaware. The Delaware System is the largest of the three and supplies between 50% and 70% of the City’s daily water supply. In the 1990s, the NYCDEP discovered leaks in the central 45-mile-long (72 km) portion of the Delaware Aqueduct known as the Rondout-West Branch Tunnel (RWBT). The leaks release between 15 and 35 million gallons per day (MGD) (132.5 million liters per day) and are concentrated in two areas near Wawarsing and Roseton, New York. As part of the Rondout-West Branch Bypass Tunnel and Wawarsing Repairs Project (Bypass Tunnel Project), the leaks in the Wawarsing area will be repaired by grouting from inside the existing RWBT, and the leaks in the Roseton area will be mitigated by constructing a bypass tunnel parallel to and 1,750 feet (533 m) north of the leaking portion of the existing RWBT. Two deep shafts will be excavated on either side of the Hudson River: Shaft 5B in Newburgh and Shaft 6B in the Town of Wappinger."

Jan 1, 2016

By Mark Lawshe, Shosie Serata

The conventional method of mining underground, using narrow rooms and wide pillars, has proven to be poorly adapted to the powerful earth forces that act on underground openings. The high costs of roof bolting, timbering, steel arching, and other means of artificial roof support for both room-and--pillar operations and longwall gate roadways attest to the limitations of traditional mine design. Too often, productivity halts when corners buckle under "cutter roof' stresses, floors heave, and roof strata fall. In the 1960s, an entirely different approach to strata control was developed. The Stress Control Method (SCM) stabilizes failing roofs and heaving floors by removing the cause of failure - highly concentrated stresses around the openings. This is achieved by regrouping three to 10 rooms into a single entry where the rooms are separated by very narrow yielding but stable pillars. SCM employs a specified excavation sequence to redirect earth pressures away from the mine openings. The yield pillars act as scaffolding until a permanently protective secondary stress envelope forms around the entry (lower part of Fig. 1). The result is a dramatic improvement in roof stability and a significant reduction in artificial support costs. Some roof bolting must still be done, mainly to meet Mine Safety and Health Administration (MSHA) requirements. Potash, salt, coal mining The stress control method was first applied to the deep potash mines of Saskatchewan. The new SCM design actually increased room widths to enlarge the stress envelope, redistributing the stress concentration away from the entries (Serata and Schultz, 1972). This resulted in a turnaround from pervasive roof fall/floor heave conditions that threatened operations in the eight new mines opened in the Saskatchewan potash field during the 1960s. In addition to eliminating all roof bolting, SCM successfully stabilized ground conditions and substantially increased productivity over the original design (Serata, 1976, 1982). Similarly, the deep Boulby potash mine of Yorkshire, England, was about to close after various conventional means of combating roof failure had failed. An SCM test area was excavated that resulted in the ground quickly stabilizing without need o artificial support (Serata, 1982; Chilton and Laird, 1982). Another example is the Diamond Crystal salt mine in Louisiana. Here, multiple level mining was being extended from the third to the fourth level downward in the Jefferson Island salt dome. Extensive roof failure was occurring at 396 m (1300 ft) ii the third level. SCM design principles in creased the room size from 24 to 49 m (80 t( 160 ft) on the fourth level at a depth of 457 m (1500 ft). This unprecedented expansion of room width was first questioned and later ap¬proved by MS HA, which expressed satisfaction in seeing the improvement documented by field validation data in 1973. The most recent SUM application to salt mining has been in the Michigan Basin a: Goderich, Ontario. The anticipated abandonment of Domtar Chemicals Group/Sifto Salt Division's deep operation in bedded sale was prevented by a multi-year SCM implementation. The success of SCM in dry mining[lecc] to its application to solution mining of salt This adaptation of the method is now being implemented in bedded salt at Fort Saskatchewan, Alberta by Dow Chemical Co., and in St. Clair, MI by International Salt Co. Application of SCM to solution mining in a salt dome is proceeding at Napoleonville. LA by Dow Chemical. The same technology has also been applied to cavern design for the Louisiana Offshore Oil Port (LOOP), and the compressed air energy storage (CAES)

Jan 1, 1989

By J. Partyka, J. S. Stachulak

Dust produced during blasting in a copper/nickel based mine was studied and characterized. A stope utilizing the crater blasting technique, or the vertical retreat mining (VRM method), was examined. Two dust monitors were used to measure an airborne dust produced during blasting operations. The data collected in situ was primarily used to formulate the boundary value problem for a generalized equation that describes the transportation process of airborne dust from all places where dust is produced by the VRM mining method. The field data was also used to define the analytical forms for the initial and boundary conditions, to provide a simple and reliable equation for flow of dust in a stope vicinity, and to identify the non-measurable constants. The effects of the amount of blasting material and of the ventilation system in use on dust concentration are also discussed.

Jan 1, 1995

By G. Bezuidenhout

The newly developed Bateman Flotation Machine has proven its versatility in roughing and cleaning flotation circuits. This mechanical flotation machine has the dual performance capability of suspending solids and dispersing air at relatively low power inputs without compromising these two important fundamentals. This new development has been successfully marketed to a wide cross section of concentrator mineral processes. The mechanical design of the flotation mechanism has been optimised to reduce operational costs and to lower manufacturing costs. Production process environments were utilised for verification of the scale-up of each cell volume size rated mechanism. These thorough investigations produced performance data which could be accurately quoted. This paper is a historical account of the Bateman Flotation Machine. Technical details of the development are covered with descriptions of the operational applications.

Jan 1, 1995

By V. Nasri, S. Rashidi

The Baltimore Red Line Project is a proposed 22.7-km (14.1-mile) long east-west light rail transit (LRT) line envisioned to connect the areas of Woodlawn, Edmondson Village, West Baltimore, downtown Baltimore, Inner Harbor East, Fells Point, Canton and the Johns Hopkins Bayview Medical Center Campus. The Red Line LRT System has two tunnel segments - the Cooks Lane Tunnel (CLT) and the Downtown Tunnel (DTT). The CLT segment is roughly 1,920-m (6,300-ft) long. It commences at the west portal located at the highway ramp for I 70 (to be removed) and terminates at the east portal that is at the intersection of Edmondson Avenue (U.S. Route 40) and Glen Allen Drive. This segment of the project consists of the following construction components: approximately 1,458 m (4,786 ft) of tunnels, 143 m (469 ft) of cut-and-cover tunnel, and 318 m (1,045 ft) of retained cut (U) section. The approximate horizontal alignment for the Red Line LRT Project is shown in Fig. 1.

Jan 1, 2014

By Bryan Ulrich

On March 15, 2012, about 24 attendees from several western states attended Roundtable 2012, hosted by Knight Piésold and Co. at the Red Lion Hotel and Casino in Elko, NV. The focus of this year?s discussion was ?Acid Rock Drainage for Engineers and Environmental Scientists.? Other names may have been more suitable for the event, perhaps combining geochemistry, with air and water quality and their long-term effects on soil and rock mechanics. Bryan Ulrich (senior vice president, Knight Piésold?s Nevada operations) and Steve Lange (senior geochemist, Knight Piésold, Denver, CO), helped facilitate the discussion. Attendees included personnel from a dozen mining properties, various corporate offices and academia. There were also attendees from a geochemical testing laboratory to help respond to specific questions pertaining to testing protocol and procedures.

Jan 1, 2012

By L. G. Austin, R. S. C. Rogers

INTRODUCTION Coal is geologically a sedimentary rock with distinct bedding planes containing a mixture of petrographic constituents. Yet. because of its chemical nature, it also has some of the characteristics of a polymeric material. In addition, it is extensively precracked to give a macropore structure and also has a substantial internal volume of microporosity. Add to this the mineral constituents dispersed in the coal in a variety of forms and sizes. and it can be readily appreciated that coal is a complex and heterogeneous material. It has to date not been possible to predict the particle size distributions produced by breakage of coals from a priori application of the principles of fracture mechanics. However, there is a substantial body of data resulting from empirical observation of size distributions produced under various conditions, primarily from grinding mills. It is the function of this review to outline how this empirical information can be used to predict product size distributions for those systems which have been studied systematically, and to suggest future avenues of research using similar methodology. FRACTURE THEORY APPLIED TO COAL It is, of course, possible to devise experiments for slow crack propagation in a coal. However, the evidence is that coal breaks by brittle fracture in the mills and mining machines of industrial importance and therefore the theory of brittle fracture is sufficient to illustrate the important features of the fracture of coal. In order to produce size reduction a solid must be stressed by the application of force. The force can be a tensile (stretching), compressive, or shear force, and the three dimensional stress pattern in the solid represents the tensile, compressive, and shear forces per unit area acting in any direction through any point in the solid. As an illustration consider the case of a simple one-dimensional tensile stress: then stress is defined as a=F/A where F is the force. A is the cross-sectional area of the solid normal to F and strain. E, is defined as the fractional change in the length of the solid. so that E= x/L where x is the extension of an original length of L. Coal behaves as an elastic material over short times (although viscoelastic creep can occur if the stress is maintained over long times) and if it is not stretched too far the coal returns to its original shape when the stress is removed; otherwise catastrophic failure occurs and the coal fractures at a stress termed the tensile strength. The failure under stress of an elastic material is termed brittle fracture. Elastic material fails at small stain and the stress-stain relation to where brittle fracture occurs is the empirical Hooke's law. a= YE, where Y is Young's modulus. The work done on the solid to take the solid from zero external stress to a stressed state by slowly increasing F up to a final stress u is the integral of the stress times the strain. This reversible strain energy is stored in the solid and. using Hooke's law. is u /2Y per unit volume of solid. If the solid is immediately loaded to u the work done is [EAuL] which Is a2 /Y per unit volume, that is, twice the reversible work.

Jan 1, 1988

By Michael E. Kelahan, Charles Y. Guan, Glenn A. Gruber

A comparison of the IMC Anionic Process and the CLDRI Process, based on pilot plant testing of waste pebble by Jacobs Engineering is presented. Estimated costs for constructing and operating a beneficiation plant utilizing dolomite flotation are given. Research to develop practical flotation processes for removing dolomite from low-grade phosphate rock has been a high priority for the Florida Institute of Phosphate Research. The Institute funded the above pilot plant programs in 1998 and 2000. The Florida Phosphate industry currently deals with the increasing dolomite content of ore reserves by practicing selective mining. Heavy media separation plants installed at two mines to remove dolomite from pebble are not being operated. The flotation separation of dolomite from waste pebble requires that the flotation feed be ground. Grinding liberates the mineral species and produces particle sizes small enough to be floated. Only two dolomite flotation processes, the IMC Anionic Process and the CLDRI Process, have been successfully demonstrated on flotation feed that has not been deslimed after grinding. Deslimed flotation feed, relative to undeslimed feed, has improved flotation performance and reduced reagent consumption. However, for the above mention processes, undeslimed ground feed increases the yield of concentrate because the phosphate desliming losses are avoided.

Jan 1, 2002

By R. L. Atwood

The structure, properties, and composition of commercial chelating-type copper extractants are examined. Characterization of these extractants was accomplished using organic separation techniques and analytical tools such as NMR and IR. Results indicate that only the trans isomer of the diphenylhydroxyoxime (LIX (R) 64N) is capable of copper chelation. The effect of the structural modification of the extractants on the extraction and stripping reactions are discussed.

Jan 1, 1972

By Richard W. Kimball, Richard F. Coon

This paper describes drill and blast excavation and groundwater control measures at the Lake Mead Intake No. 2 project. The construction includes a deep access shaft, intake shaft, surge chamber, forebay chamber, intake tunnel, 22 well shafts and East Tunnel. Grouting ahead of the excavation face was used extensively during shaft and tunnel construction. Lake Mead Intake No. 1 was constructed in the early 1970’s under less severe groundwater conditions and this work was delayed by ground conditions and water control problems. Excavations for Lake Mead Intake No. 2 must be completed in 23 months to meet SNWA’s water delivery schedule.

Jan 1, 1999

By Douglas J. Kramm

This paper discusses the history and development of the Rotary Kiln in improved fuel economy. It discusses latest technology to optimize fuel economy in a long Rotary Kiln. It discusses the limestone preheater, the SF process for cement manufacture, and the flash calciner with suspension preheat and. suspension deheat for fine limestone.

Jan 1, 1977