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By Robert G. Pinkerton

Boyles Bros. Drilling Co. and Gibbons and Reed Company, both of Salt Lake City, Utah, have successfully combined into two joint ventures on the San Juan-Chama project of the U. S. Bureau of Reclamation. The Azotea Tunnel is 12.7 miles in length; the inlet portal is on the Navajo River in Archileta County, Colorado, and the outlet portal is in New Mexico, about 10 miles south of the state border. The Oso Tunnel lies immediately to the north of the Azotea Tunnel and discharges water directly into it. We are presently driving both tunnels with mechanical boring machines from their portals at the Navajo River. Both tunnels are circular, fully concrete lined. The Azotea Tunnel has a finished diameter of 10 ft. 11 inches while the Oso Tunnel is 8 ft 7 inches in diameter. Both tunnels are supported with circular, structural steel rings as required by ground conditions. In good ground rock bolts and steel roof plates are used.

Jan 1, 1967

By F. L. Pierson

Since the discovery of 'potash in the Carlsbad area in 1926 and the start of mining operations in 1931, "first mining," operations have been carried on. This is a room and pillar system in which approximately 62% of the total ore is removed. Or the basis of ore reserves and rates of extraction, the life of the mine in the early; days was estimated to be well over 50 years, however, even with an increase by additional ore reserves, it became increasingly apparent that the life of the mine was being shortened considerably by increased production. Further cause for the shortening of mine life was due to the exceptionally weak back over the northeast quadrant of the main orebody which had .caved in on first mining up to a height of 8 feet. Thus, in 1953 the decision was' made to begin pillar pulling, also called, second mining or final mining, and in December of 1953 this program was started after much discussion.

Jan 1, 1965

By E. L. Fidler, T. E. Finch

Wayne Anderson Regarding the technical paper by Thomas E. Finch and Edward L. Fidler, "Recovery of Stray (Thin) Seams in Western Coal Mining." I would like to comment on this subject. In western Canada, most strip mines encounter thin seam coal or rider seams. Although the paper addresses the problems and costs associated with the recovery of this coal, it does not take into account what the savings are. Without looking at the savings, the "Total Objective" is of course not clear. I feel that in a stripping operation the mine can spend per ton (of the thin seam) up to their dragline stripping costs per ton to recover a rider seam or thin seam. The reasoning behind this is simply that this is the price the mine will have to pay to expose an equivalent amount of coal without the recovery of these thin seams. If the mine can recover a rider seam or thin seam for less than the dragline operating costs per ton, a savings will be realized. By recovering a thin seam or rider seam, the life of an ore body is extended by that amount of coal not thrown away. In addition, the cost of land acquisition, associated permits, capital, and reclamation will be reduced as more coal is delivered for a given area. When the above points are considered, the recovery of these thin seams can be very profitable and indeed worth recovering.

Jan 11, 1982

By D. W. Scott, D. G. Minnes

Introduction Ontario's diverse industrial mineral resource base includes structural minerals such as sand and gravel, crushed stone, building stone, clay, shale, limestone, and dolostone. These resources are used to produce aggregates, brick, metallurgical stone, fillers, cement, lime, and other construction materials. The majority of the operations are in deposits of Palezoic and Quaternary age in southern Ontario, close to the major markets. Province-wide, there were more than 140 Mt (154 million st) of aggregates produced in 1985. About 115 Mt (128 million st) of that was produced in southern Ontario with the rest being largely from Crown land in northern Ontario. Structural industrial minerals account for more than 80% of the value of total industrial mineral production. The remaining 20% is accounted for by the nonstructural minerals, such as salt, which is produced in the southwestern part of the province. A host of other nonstructural industrial minerals are known. Production, though, is currently restricted to calcite, gypsum, quartz, talc, nepheline syenite, and byproduct metallurgical sulfur products (Fig. 1). Major production is close to the large markets of urbanized southern Ontario and the northeastern and northcentral US. With an abundant variety of industrial mineral resources and the large population within 650 km (400 miles) of most deposits, the market offers great potential. Ontario's nine million people accounted for about 35% of Canada's entire $476.3 billion gross domestic product in 1985. This equates to about one-third of the nation's buying power being within a 200-km (125-mile) radius of Toronto. This major concentration of industrial and economic activity has resulted in a well-developed industrial minerals industry that fulfills most of the structural industrial minerals demand in Ontario. Nonstructural industrial minerals are similarly well placed to compete in this high demand area. Although Ontario manufacturers still import some of these materials, Ontario products are achieving significant market share. And, they serve the needs of neighboring provinces and states. Present production and trends Ontario has traditionally produced significant amounts of industrial minerals. This produc¬tion had a value of $956 million in 1984 (Table 1). Structural materials production in 1985 and 1986 approached or exceeded levels not seen since the early 1970s. Many new products have been developed using these raw materials. The industry is becoming concentrated in the hands of several large companies, mainly four large cement com-

Jan 12, 1987

By C. W. Grate

Cooperative Education is by no means a new idea. The first such program was instituted at the University of Cincinnati in 1906 by the late Dean Herman Schneider with twenty-seven engineering students participating. Today, more than fifty years later, there are in excess of one hundred institutions' with some such program in which thousands of students, are participating in the fields of Liberal Arts, Engineering, and Business Administration. At the same time, according to a conclusion reached during a study of work-study college programs, copyrighted in 1961 by Thomas Alva Edison Foundation, and from which we quote; "We were amazed at the lack of-information about cooperative education among school and college staffs and students, among parents and employers, and on the part of the public generally."

Jan 1, 1963

By D. P. Bryan

The identification and-develop¬ment of new construction aggregate resources, the most common mineral mined, is an essential need in this country's growing urban areas. In developing an aggregate exploration program, a thorough geological identification of all potential aggregate resources in an area is still of primary importance but other factors have also to be considered. These include physical properties, end product application, transportation and mining costs, and local government regulations including zoning. The present major aggregate producers are most likely to develop these future resources and are in the best position to initiate comprehensive exploration programs.

Jan 1, 1987

By C. L. Pillar

In the capitalistic system the success of a mining enterprise is measured by the rate of return on the investment and the speed by which its redemption is achieved. Exploration in search of ore deposits often results in the emergence of the lean orebody which does not meet basic company requisites. At this point a decision must be made whether to place the orebody into production or postpone production pending more favourable market conditions. The wisdom of this decision, borne out by future results, demonstrates the quality of a company's management and is instrumental in the degree of financial success it achieves. The project feasibility report must show a rate of return on the capital invested that is attractive to the company, plus its full redemption in the desired period of time, in order to bring the property into production on a sound economic basis. Mining companies have demonstrated their ability to bring the profitability of a marginal property from a point that says "no go" to a point of "go" by substantial reduction of expenditure without adversely affecting production rate or cost. Here is where the real challenge exists for today's mining engineers and plant designers; they will have to develop better ideas and concepts: ideas that will still allow maximum production at reduced capital expenditure, This is the sound way marginal orebodies can be brought into production without inflationary increases in the price of their product.

Jan 1, 1969

By Byron M. Jones

The use of computers in system analysis is well established. Analog computers have been used for this purpose since about 1940. As the power of digital computers increased and their cost decreased, much of the analysis formerly done by analog computers has been diverted to digital computers. The mathematical foundation for system analysis was laid between the years 1700 and 1900. In the 1930?s, telephone repeater amplifiers were designed using systems analysis techniques. From 1940 to 1960 systems were analyzed using either direct simulation or LaPlace transforms. Since 1960 analytical methods have been expanded to include linear vector space theory. All of these methods are being used to analyze the dynamic behavior of mining machinery.

Jan 1, 1974

By B. A. Kennedy

The instrumentation, monitoring, and prediction of a major slope failure at the Chuquicamata mine are described. In December 1967, pre-existing tension cracks on the south end of the east wall of the Chquicamata mine began to open. Various forms of instrumentation were installed for continuous monitoring. These systems included tension crack stakes, crack extensometers, linear extensometers, tape and transit lines, sliding wire contacts, and a seismograph. From the information obtained, the failure date was accurately predicted some five weeks before failure, enabling the mine to reroute truck and rail access; hence, causing a minimal mine shutdown of two and one-half days and preventing any injuries to persons or damage to equipment. The shape and form of the sliding mass are analyzed, as are the possible modes of failure.

Jan 1, 1970

Exploration for SX-EW copper deposits and plant operation depend largely on the copper and gangue mineralogy inasmuch as? they govern the feasibility of leaching. Mineralogical parameters are pivotal in identifying if an ore is suitable to dump, heap, thin layer, vat or agitated leaching and/or if the ore requires curing, bioleaching or alternate lixiviants. Problems in metallurgical testing, production leaching and recovery forecasting are very often related to lack of mineralogical data. This presentation will illustrate the use of quantitative mineralogical analysis for exploration, acquisition assessment and optimization of copper leach operations.

Jan 1, 1996

By Dani Delaloye, Kas Zurek

Evaluating and selecting the appropriate excavation method is a key to the success of any tunnelling project. The benefits and risks of different methods should be well understood by the designer and communicated to the project owner to enable selection of a preferred method from a technical, social and environmental impact, cost and constructability perspective. For tunnels that have an internal diameter around 3 m, depending on the tunnel purpose and ground conditions, both microtunnelling with pipe jacking and tunnel boring machine excavation with a one- or two-pass lining may be feasible construction methods. Using the Ferry Road and Riverbend Combined Sewer Relief Project located in Winnipeg, MB as a case study, this paper will discuss the benefits and drawbacks of each method, including technical design, social, environmental, cost, schedule, and risk considerations.

Jun 13, 2023

By M. Yekich, W. R. Reed, G. Ross, M. Shahan

"Canopy air curtains (CAC) on roof bolting machines have been proven, through laboratory and field investigations, to protect miners from respirable dust, preventing dust overexposures. Another desired application is to develop a CAC that is mounted in the compartment of a shuttle car to protect the operator from dust. The challenges faced with this design include mine ventilation rates in tandem with the shuttle car tram speeds, causing cab airspeeds that may exceed 600 fpm, as found in this study of a central Appalachian underground coal mine. Prior research and laboratory testing indicate that successfully protecting a miner in high air velocities is difficult to achieve because the clean air from the CAC is unable to penetrate through the high velocity mine air and make it to the breathing zone of the operator. During this investigation by researchers from the National Institute for Occupational Safety and Health (NIOSH), dust concentrations of the shuttle car operator were measured. Also, air velocities experienced by the operator were measured using a recording vane anemometer. Results from the survey indicate that the highest exposure to respirable dust (2.22 mg/m3) occurred when the shuttle car was loading at the continuous miner, where there was an average airspeed of 157 fpm. While tramming, the operator was exposed to 0.77 mg/m3 of respirable dust with an average airspeed of 203 fpm. This study indicates that a CAC system can be designed to greatly reduce an operator’s exposure to respirable dust by providing clean air to the operator, since the majority of the operator’s dust exposure occurs in air velocities less than 200 fpm. INTRODUCTION NIOSH has issued a contract (#200-2015-63485) with Marshall University and J.H. Fletcher & Co. (Salem et al., 2016) to develop a canopy air curtain (CAC) for coal mine shuttle cars. The proposed design maintains a similar design to the roof bolter CAC by providing filtered air via a blower over the operator. The plenum, which will provide the uniform airflow over the operator, is anticipated to be built into the shuttle car canopy. One of the main interferences with a CAC is ventilation airflow perpendicular to the plenum airflow [Engel et al. 1987]. This ventilation airflow, if the velocity is significantly high, can shear the downward flow from the plenum. The shear caused by the ventilating airflow can reduce the effectiveness of the CAC by either disrupting the downward flow or allowing contaminated mine air into the CAC zone of protection."

Jan 1, 2018

By O. Ozcan

Oleic acid has been almost invariably used in the flotation of siliceous fluorite ores. The performance of oleic acid, however, deteriorates with carbonaceous fluorite ores. Oleoyl sarcosine developed recently has been found to produce results superior over oleic acid with ores containing high calcite contents. While the mechanism of oleate adsorption is usually considered as chemisorption involving calcium oleate formation on both calcite and fluorite, no mechanism has been so far proposed to explain the adsorption mechanism of oleoyl sarcosine. In this study, the selectivity of oleoyl sarcosine, as inferred from flotation, zeta potential and infrared measurements, is ascribed to the interaction of fluorine ion to the nitrogen via hydrogen bonding.

Jan 1, 1994

By Norman F. Schulz

Representative sample s of typical manganiferous iron ores from the Cuyuna Range, Minnesota, were reduced to the metallic iron state at temperatures just short of fusion with an excess of coke in the manner prescribed by the R-N Direct Reduction Process. The magnetic separation characteristics of the reduced ores were determined at several grinds by means of the Davis magnetic tube concentrator. The efficiency of metallic iron concentration by magnetic separation was a direct function of the degree of metallization of the ore sample and of the degree of liberation attained in grinding. Some improvement of liberation characteristics was observed if a small amount of sodium chloride was present in the ore during reduction. Despite the extremely fine -grained structure of the crude ores, iron concentrates containing more than 90% Fe at iron unit recoveries of 90% or more were obtained from well-metallized samples of three of the four ores tested. The rejection of manganese to the tailings corresponding to such separations varied from 80 to 95%.

Jan 1, 1967

By G. R. Harrod

Effective mine operation demands that the right people have the right information at the right time. Caterpillar's Mining and Earthmoving Technology System (METS) meets this demand by providing "real-time" information transfer between the mine offices and machines equipped with the Caterpillar Computer Aided Earthmoving System (CAES). Transfers of mine plans from the mine planning software to CAES-equipped machines give operators access to current mine plans within minutes of their creation. Additionally, office personnel have access to a current digital terrain model (DTM) of the mine site as it is updated in "real-time" by CAES-equipped machines. METS provides mine personnel in operations, planning, and management the information they need when they need it.

Jan 1, 1998

By M. Visnjic

Open Pit Mine Production scheduling under commodity price uncertainty suffers from an exponentially increasing problem size as simulations and real options flexibility are used to generate and evaluate multiple production schedules. Robustness evaluation techniques attempt to evaluate a production schedule that is generated on a single set of economic parameters against several varying prices and sources of uncertainty. This approach is invalid as the corresponding optimal LOM mine plan will change for each set of evaluation parameters. Using commodity market futures and treasury bonds as production schedule economic input parameters provides fully price and time-value-of-money risked scheduling parameters that maintain a deterministic problem size. This paper will provide comparative analysis of project NPV’s coming from traditional price uncertainty evaluation based on a single fixed LOM mine plan using varying prices versus evaluation based on varying LOM plans that are both generated and evaluated using varying prices. When cross evaluating constant price mine plans against simulations, the upside potential and downside risk of a project are significantly misrepresented. INTRODUCTION The life of mine (LOM) production scheduling problem seeks to answer the question of from where and when to extract a given block within the ultimate pit limit as well as where and when to process it. Solving this problem takes into account the constraints of extracting any particular block while seeking to maximize the net present value (NPV) of the mineral asset as a whole. A direct driver of the value of a block, and there for the entire asset, is the market price of the commodity in question. Complications arise when an optimal production schedule is attempted to be solved under price uncertainty. Many solution methodologies have been proposed in an attempt to optimize under this criterion, yet there are three salient aspects that are overlooked during this process. They are: • Generating a single production schedule and evaluating it against many simulated price paths. • Failing to understand the mechanism describing particular commodity price behavior • Inappropriate risk adjustment In an effort to address these aspects of production scheduling under commodity price uncertainty, we propose a methodology to define the economic parameters as input that is applicable to most if not all production scheduling approaches. This methodology will not only simplify the production scheduling process in terms of establishing block value but utilizes the risk adjustment of real options valuation to avoid the arbitrary blanket risk adjustment of traditional discounted cash flow valuation. Our findings conclude that attempting to optimize around individual price paths is futile and using a market risk adjusted single price forecast provides a justified economic basis for production scheduling while maintaining the same problem size as a deterministic production scheduling problem.

Jan 1, 2019

By M. Liu

In-situ soil washing using surfactants shows great potential to remove hydrophobic organics from subsurface environment. Lab scale soil washing experiment were performed using Sodium Dodecylsulfate (SDS), an anionic surfactant, and anthracene, a highly hydrophobic compound. The results of this research show that solubility of anthracene increases linearly with an increase in SDS concentration above the critical micelle concentration. Furthermore, SDS can be effective in removing anthracene from contaminated sand.

Jan 1, 1992

By John D. Nelson

Unprotected uranium mill tailings impoundments can pose a significant risk to nearby inhabitants and the surrounding environment in the event of a prolonged or catastrophic release of contaminants contained in the tailings. As a result of this potential, reclamation plans for such facilities must include engineering designs to protect against disruption of the tailings and the potential release of radioactive materials. The goals for such engineering designs should be to provide overall site stability for long-term periods with no need for planned ongoing maintenance and to provide a repository for the tailings that will not place a burden on future generations. Although the goal is to provide a maintenance-free system that does not require monitoring, it must be recognized that some period of surveillance would be reasonable. The surveillance period could be relatively short and only needs to assure with reasonable confidence that the reclamation scheme that was implemented is functioning adequately. An investigation was conducted by Nelson, Volpe, Wardwell, Schumm and Staub (1983) entitled Design Considerations for Long-Term Stabilization of Uranium Mill Tailings Impoundments (NUREG/CR-3397). This report assesses the degree of confidence with which long-term reclamation plans can be expected to remain effective over specific periods of time, and to assess the additional effort required to extend the design period from one long-term period to a longer one. This paper presents a summary of that investigation and discusses some of the important conclusions.

Jan 1, 1984

By P. Zhu

The leaching behavior of copper powders recovered from waste printed circuit boards (WPCBs) was investigated using electrogenerated chlorine and aeration in a sulfuric acid solution with added NaCl and CuSO4. Various parameters were studied to understand the mechanism of the copper leaching. When the current density increased from 0 to 0.1 A/cm2, the temperature from 30 to 60° C, agitation speed from 100 to 400 rpm, and the size ranged from below 75 to 150 µm, the leaching ratios of copper powders increased. The leaching kinetics were analyzed using a shrinking core model: 1-(1-X)1/3 = kt, and the leaching process was chemically controlled with an activation energy of 14.7 kJ/mol due to Cl- ion catalysis. The ratios of [Cu+]/[Cu2+] at various temperatures (30, 40, 50, 60 and 70° C) showed a periodic variation with the increasing of the leaching time. The redox potentials of the leaching solution and copper leaching ratios in different conditions were measured. The result indicates that dissolved oxygen achieved the dissolution of coppers and electrogenerated chlorine can promote the dissolution of copper powders and improve the reaction rate of kinetics in the presence of oxygen.

By Weijie Wei, Jinwang Zhang, Shengli Yang

In longwall top-coal caving (LTCC) mining with an inclined seam, the recovery rate is low and equipment stability is poor due to the unbalanced top-coal drawing process. To address these problems, this paper proposes the dynamic group caving method (DGCM), whose basic premise is that when the drawn volume of top coal from a support reaches about half, the next support begins drawing top coal, and the drawing process between the two supports is half done. Using particle flow code (PFC), the caving mechanism of top coal under DGCM was investigated. The results are of significance to realize high efficiency and precise caving in LTCC mining with an inclined seam.