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By Pierre Rocque

The Red Lake Mine is located approximately 600 km northwest of Thunder Bay. This 545 tpd (600 tons/day) underground narrow vein gold operation is set to produce in excess of 14.8 tonnes (475,000 ounces) in 2001 at a cash operating cost below 75 U$/oz. The high-grade nature of this deposit (>55 g/t or >1.6 opt) coupled with its complex geological environment and relatively deep location dictated the choice of a very selective primary mining method, Mechanized Overhand Cut and Fill. In addition to geological challenges, mine design issues such as material handling, ground stability and requirements for yieldable ground support are also discussed in this paper.

Oct 1, 2001

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

Energy dissipation and fragmentation of rock is of interest for mine-to-mill operations in order to understand breakage and to minimize energy consumption during blasting at the mine site, and comminution at the processing plant. In this regard, high velocity impact breakage of long granite cores, called bars, has been studied with instrumented strain gages to follow the energy dissipation gradient along the bar length resulting from the strain waves generated by impact. As a result of high velocity impact, three zones have been identified (fragmentation, fracture, and elastic) and these three zones have been characterized in 3D using X-ray tomography. The fragmentation zones of the granite bars were studied in detail to describe the particle size distribution and the particle shape characteristics. Finally, the experimental energy dissipation for the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work equation, if the anisotropic granite particles are defined by length rather than by sieve size.

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

Energy dissipation and fragmentation of rock is of interest for mine-to-mill operations in order to understand breakage and to minimize energy consumption during blasting at the mine site, and comminution at the processing plant. In this regard, high velocity impact breakage of long granite cores, called bars, has been studied with instrumented strain gages to follow the energy dissipation gradient along the bar length resulting from the strain waves generated by impact. As a result of high velocity impact, three zones have been identified (fragmentation, fracture, and elastic) and these three zones have been characterized in 3D using X-ray tomography. The fragmentation zones of the granite bars were studied in detail to describe the particle size distribution and the particle shape characteristics. Finally, the experimental energy dissipation for the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work equation, if the anisotropic granite particles are defined by length rather than by sieve size.

By V I. McCallum

In 1954, Falconbridge Nickel Mines Limited began the program of deepening the Falconbridge mine workings for 2,000 feet below the bottom, or 4025, level in order to provide twelve new levels for production. Involved in this program were a production-sized internal shaft, .crushing, pumping and hoisting installations, the integration of the new shaft operations with those of existing shafts, and considerations of ventilation requirements and ground support at depth. This paper describes the major items of equipment, and the depth development of No. 9 shaft as a whole, and also emphasize the planning phases of the program. The factors involved and reasons for the equipment and layouts chosen are given. Introduction and History THIS paper describes the planning and development of that portion of the Falconbridge mine between the 4025 and 6050 mining levels. This mine, the oldest of several being operated by Falcon-bridge Nickel Mines Limited in the Sudbury district, has been a continuous producer for over thirty years.

Jan 1, 1964

By Steve Polegato, J. Coady Marsh, Gary Landry

The Donkin-Morien Mine in Cape Breton, Nova Scotia, has successfully completed the excavation of a 7.6m (25-ft) diameter access decline over a distance of 3.5km out under the Atlantic Ocean. The tunnel, completed in December 1984, was driven through a sedimentary sequence of sandstone, siltstone, mudstone and various gassy coal seams prior to intersecting the Harbour Coal Seam where development work will commence. The tunnel was driven by a Canadian prototype tunnel boring machine (TBM) manufactured by Lovat Tunnel Equipment, Inc., Toronto, Ontario. The 7.6m (25-ft) diameter full-face shielded TBM operated at various grades from 0-20%. This paper outlines the TBM design, excavation, support and backup system utilized in the drivage. Problems encountered and drivage rates will be addressed.

Jan 1, 1985

By Ilpo O. Auranen

Background: Mines of today are moving ever increasing tonnages of rock. The new ore bodies tend be of lower grade and located deeper in the earth?s crust. The industry?s focus to overcome this ?deeper but poorer? ore problem has traditionally been to lower the costs by increasing the scale of mining. This has resulted in an ever increasing size of mining equipment like drills, loading shovels, dump trucks. The main focus has been in reducing the cost per ton of mining. This cost focus has often resulted in increased waste rock dilution and more ore losses. From costs to value: Waste rock dilution means waste rock in the concentrator feed. It?s value in open pit mining is equal to the value of ore it replaces. In underground mining, waste rock dilution?s value is equal to the value of ore it replaces added to the costs of mining it. It is commonly accepted that waste rock dilution in open pit mining ranges between 5 and 20% and in underground mining between 5 and 40 % . In a typical large open pit mine ore value is from 20 to 60 USD per ton and mining costs are 1 to 3 USD per ton. One percentage point reduction in waste rock dilution represents savings corresponding to about 20% of total mining operation costs. The difficulty of reducing waste rock dilution comes from the complicated nature of the ores. Accurate ore waste-border detection has not been possible due to excessive costs. Core drilling combined with geochemical lab analysis is the most accurate method for locating ore waste borders. However, it is also expensive and time consuming, which is why it is often combined with somewhat lower cost methods like sampling drill cuttings from blasting drill holes or from reverse circulation drills and analyzing them in a laboratory. The main drawback with these methods, in addition high costs, lies in the sampling accuracy and in the quality control of the whole process when a large number of samples have to be handled manually. In every mine it is possible to halve waste rock dilution by using new on-line analysis technology .

Oct 1, 2009

By Junya Tokita

In Japan, packaged explosives have traditionally been used as the most common explosive for tunneling. Recently, some blasting systems such as ANFO with a kettle loader and emulsion explosives with a pump loader have been trialed in order to improve safety and efficiency of the charging process. There are issues with these systems relative to the Japanese market. ANFO dissolves in water easily, and generates ammonia gas when it contacts with concrete. Emulsion explosives need costly pump ing unit s, and there is a need to control residuals in the pump unit. Additionally, there are obstacles by Japanese law to site mixing of emulsion explosives.

Jan 1, 2005

By P. Hajiani

"It has been shown that the economics of the hydrometallurgy of a rare earth process depend upon the amount of acid needed to extract the metal per unit mass of the ore. In this paper, we show how to save a significant amount of acid treating a low grade ferrocarbonatite and extracting +99% constituent REEs. In order to save the acid, the alkali earth metals, originated from gangue minerals were removed prior to REE leaching. Moreover, the operating conditions of leaching reactor are optimized to leave iron behind and to leach REE selectively and effectively. Consequently, the hydrochloric acid consumption per ton of ore drops significantly compared to other processes.INTRODUCTIONThe viability of an extractive metallurgy process of rare earth elements (REEs) to produce an intermediate mixed concentrate depends upon a low-cost simple flowsheet (Bogner, 2014). It has been known that regardless of the mineral, the acid consumption is intimately associated with the operational cost (OPEX) of any REE project, particularly when the initial REE grade is low. Besides acid, the other reagents consumed in the process impact the OPEX. This makes minimizing acid consumption in an REE method a critical priority. The acid consumption in different projects has been reported to be equivalent of 100 kg to 1000 kg HCl (100%) per tonne of ore (Average: 500 kg/t HCl 100%) (Bogner, 2014). This value is strongly correlated with the grade of REE in the ore and therefore in the pre-concentrate.Previously, it has been stated that the Montviel flotation concentrate requires about 300 kg HCl (100%)/t ore to attain +99% REE recoveries using direct leaching (Yu, Verbaan, Pearse and Britt 2013). Hence, for an ore feed rate of 2500 t/d ROM, a large acid production plant (744 t/d HCl 100%) would be required for acid leaching of such concentrate. The equivalent Chlor-alkali plant is estimated to cost M$ 150 (CAPEX) and may require 100 MW power. Therefore, there is a necessity to improve the extractive hydrometallurgy and to reduce the acid consumption significantly."

Jan 1, 2016

By Richard Collins

The projected depletion and the increasing costs of petroleum and natural gas along with the public and governmental resistance to nuclear energy have caused coal to emerge as one of today's answers to both our short term and long term energy needs in power generation. In order to satisfy this need, major increases in coal production are mandatory, thus requiring more and higher capacity coal transfer terminals. The logic for selecting coal as the major fuel for power generation is based on many different reports on the existing and potential energy sources, which include petroleum, natural gas, hydropower, solar, geothermal, and nuclear. The following is a brief synopsis of these reports for each type of energy.

Jan 1, 1978

The Cowarra gold mine is at latitude 36°O'S. and longitude 149°19'E. which is roughly 20 miles north-north-east of Cooma.The deposit was· originally worked towards the end of the last century, but the presence of sulphides associated with the gold in the primary zone caused cessation of work when that zone was reached.GEOLOGY AND MINERALIZATIONThe principal country rocks are sandstones and shales of Silurian and Ordovician age, both very strongly folded with structural pitches ranging from a few degrees to almost vertical. The mine proper is within Silurian rocks and the main orebody (there are several minor parallel bodies) is developed within a shear striking approximately north, dipping approximately 70° east, and ranging in width from 2 ft to 15 ft but averaging about 4 ft.This shear is impregnated with quartz and sulphides with which the gold is associated. The predominant sulphide is pyrite though pyrrhotite is commonly present in quantity.Arsenopyrite and bornite are present in smaller amounts.Stillwell (1936, 1937a, 1937b, 1938, 1941) has published five mineragraphic reports on the ore.The various levels have been mapped in detail (Figs. 1-3) and the No. 2 level plan (Fig. 1) shows the general relationship of shearing, as now indicated by mineralization, and faulting. There is no apparent connection between the fold structures and mineralization.Fig. 3 is a longitudinal projection showing the distribution of gold expressed as inch-ounces. The estimation of...

Jan 1, 1965

By D. Millgard

Dennis Millgard introduced the Session by hoping that participants to the Conference would also share their piling problems. He then invited the first speaker to present his paper. Paper 5.1. Pat Kelleher commenced by saying that he belonged to a one hundred year old firm that had experience in the New York Harbour area. They were often asked to assess the integrity of many waterside structures such as piers, walls, and docks which were deteriorating whilst still in use. The earliest structures, built in the 1800's, were on timber piles. These have now changed to Steel H and tube piles and concrete piles. Usually they were called in when the structure was showing signs of distress, or had reached the end of its life but could not be closed. In particular, they had found that marine borers had returned to New York Harbour because of the improved quality of the water. There is now a far greater incidence of attack on the timber piles than when the water was polluted. Repair is usually carried out by encapsulating the pile within the tidal range of about -2ft to +8ft (-0.6 to +2.4m). Reinforced concrete forms, reinforced fibre jackets, or nylon bags are used. Reinforced fibre jackets are used with a protective coat on the pile, while nylon bags prove the cheapest method.

Jan 1, 1991

By Howard J. Pincus

The purpose of the study is to investigate the effects of fracture fillings and associated alteration on the mechanical behavior of rocks. Experimental results are presented for 98 specimens from the Climax mine, which were tested since the annual report (May 1973). The conclusions reached are based on both these results and those reported in the annual report. The locations studied are the Climax and Henderson mines in Colorado and the San Manuel mine in Arizona. The rock types studied from each location are from: 1) Climax, medium-grained granite, fine-grained granite, granite porphyry, schist, and gneiss; 2) Henderson, rhyolite porphyry; 3) San Manuel, quartz monzonite and quartz monzonite porphyry. A description of the rocks was made including: color, texture, mineralogy, composition and fabric of fracture fillings, density, apparent porosity, and optical diffraction patterns. Unconfined and triaxial compression tests were run on the Climax and San Manuel specimens. Sonic velocities were measured during the compression tests; Shore sceleroscope hardness was measured before the compression tests. Conclusions are that some relation appears to exist between compressive strength and the following properties and features for all specimens: dynamic Young's modulus, sonic velocity, density, rock composition, slope of velocity curve, composition and fabric of fracture fillings-veinlets, and apparent porosity. There appears to be some relation between compressive strength and Shore scelerscope hardness for the quartz monzonite (San Manuel). A relation appears to exist between texture and compressive strength and the extent of failure on fracture fillings for schists, gneiss, and fine-grained granite (Climax). The amount of swelling clays (montmorillonite, hydromicas, etc.) present in the rock and the relative number of fractures in which they constitute of major portion of the fracture fillings are related to the strength of the rocks. Possible tests for checking the amount of these clays present is presented including saturation, dyes, and X-rays. A useful index relating to rock strength, as revealed in this study, is the presence of swelling clays in detectable abundances. These clays can be detected in the field with a simple wetting and striking test; in the laboratory they can be detected by X-ray and dye methods.

Jan 1, 1974

THE object of this paper is to review certain features in connection with the mining of narrow lodes, say up to 20 ft. or so wide. The types of ore-body to which it is intended to refer are those which occur. chiefly as fissure or shear-Iodes-that is, those lodes which are to be found in belts of country which have been subjected to dynamic stresses, resulting in the formation of cracks and fissures, into some of which has been concentrated sufficient metal-bearing material to form ores. Very frequently one of the walls of such a lode is found to be a fault, or plane of differential movement.The first point which comes up for consideration is the shaft and its position. From the information afforded by the prospecting which has been done on a lode relative to the dip, nature of country, &c., the position of the main hauling shaft can be determined. For purposes of general utility the hangingwall is generally chosen, if a vertical shaft, though, on account of freedom from creeps, the foot-wall would be safer. Vertical shafts are preferable to underlie shafts in many ways; but wherethe lode maintains a flat dip the cost of cross-cutting at the various levels becomes very heavy'. This difficulty may to some extent be modified· by sinking a vertical shaft in the hanging-wall...

Jan 1, 1912

The conclusions reached by den Tex after a study of the fabric of some rocks from Broken Hill have been used to support the epigenetic hypothesis for the origin of the ore, first by Edwards (1959, p. 70) and then by Stillwell (1962, p. 131) in his criticism of Segnit's (1961) views. Den Tex claimed that the petrofabric study provided "independent evidence that the ore, at least in its present form, post-dates all events of a diastrophic nature in the area concerned".Repetition of this claim by Edwards and by Stillwell and the lack of any criticism of den Tex's work for more than three years implies its general acceptance by geologists in Australia. Therefore it appears necessary to examine parts of den Tex's paper in detail to show that his, conclusions are unwarranted. The major weaknesses in his study are that1. the petrofabric study was inadequate to warrant any major conclusions, and2. the petrofabric data allow alternative conclusions.Den Tex made a single visit to the field, collected six carefully selected specimens and presented quartz and· biotitepetrofabric diagrams for two specimens, quartz-diagrams alone for three more and included three diagrams of the orientation of c-axes and fractures in one specimen. It is not reasonable to come to firm conclusions about the origin of such a complex area as Broken Hill on such inadequate data, despite den Tex's claim (p. 87, lines 22 and 23) that "a thorough investigation of the quartz-fabric of the wall rock was undertaken".Den Tex's interpretation of each diagram is open to criticism, and alternative (and to my mind, preferable) interpretations may be made. It is impossible to evaluate den...

Jan 1, 1962

By H. F. Weaver

The 17th National First-Aid and Mine Rescue Contest was held in the Kentucky Fair and Exposition Center, Louisville, Ky., October 2, 3, and 4, 1957. The meet was under the auspices of the Federal Bureau of Mines and the Joseph A. Holmes Safety Association, in cooperation with the National Coal Association, United Mine Workers of America, State mining departments, local mining institutes, and coal operators' associations. The Arrangements Committee, as authorized by the General Committee, made all the necessary arrangements for conducting the 1957 contest. Members of the Arrangements Committee were: Harry Gandy, Jr. (chairman), National Coal Association; James B. Benson, Southern Coal Producers' Association; Charles Ferguson, United Mine Workers of America; George C. Trevorrow, Bituminous Coal Operators' Association; and James Westfield, Federal Bureau of Mines.

Jan 1, 1958

By E. M. J. Alenius

This paper describing the mining practices at the United Verde open-pit mine at Jerome, Ariz., is one of a series being prepared by the United States Bureau of Mines on mining practices, methods, and costs in the various mining districts in the United States. The purpose of this paper is to present the methods used in developing and operating the mine, and to discuss the problems encountered.

Jan 1, 1930

By Hamid Maleki

Roof falls are one of the leading ground control problems that adversely influence productivity and worker safety in underground mines, construction sites, and nuclear waste repositories. To control roof stability problems, the operator needs to have practical methods for measuring changes in strata conditions and criteria for defining the timing of secondary support installation. The objective of this study was to develop measurement techniques and criteria for assessing roof conditions at the mining face. An integrated rock deformation and tomographic imaging method was developed and applied at two sites in a western U.S. trona mine. It was shown that rock damage occurred at a deformation of 30 to 60 mm (1.2 to 2.4 in) (2 to 4 pct strain) and was associated with a significant (16 pct) reduction in wave velocity. Thus, supplementary support may be installed when there is a measured change in wave velocity of at least 16 pct. Tomographic measurements can be obtained in rocks rapidly, thus providing a powerful tool for analyzing growth of failure and for installing supplementary support systems in a timely manner.

Jan 1, 1996

By William A. Beck

The K.T. Dome Mine in Owen and Henry Counties, Ky., has been operated intermittently under several different owners since the early nineteen hundreds. No record of total production is available, but it is said that during 1943 and 1944, while being operated by the Twin Valley Mining Co., 30 cars of zinc concentrates and 10 cars of lead concentrates were shipped. The vein can be traced for about 10 miles along the strike from Lockport, Henry County, to Big Twin Creek in Owen County. It pinches and swells both vertically and horizontally and is reported to average 20 inches in width. In order to develop additional reserves on the property, the Bureau of Mines drilled four holes on the south extension of the vein. Drilling disclosed that the vein dips to the west on the south side of the Kentucky River and is continuous along the strike and in depth. However, the extent of mineralization in the vein varies widely.

Jan 1, 1949

By T. Robyn

The Bolivar Cu-Zn skarn deposit in the Piedras Verdes mining district of Chihuahua is one of many base and precious metal deposits in the north-northwest trending Sierra Madre Belt extending across the states of Chihuahua, Durango and Sonora in northwestern Mexico. The information presented here is drawn from two papers on the Bolivar property1,4 plus new information. Historical mining and exploration for polymetallic Cu-Zn-Pb-Ag-Au deposits in the Sierra Madre Belt dates to Spanish Colonial days. Access to the Bolivar Property (Figure 1) is by paved road (approximately 305 km southwest from Chihuahua) and approximately 80 km by all-season gravel roads to the villages of Cieneguita (population ~1,000) and Piedras Verdes (population ~500) adjacent to the property. [ ] The Bolivar property comprises an old Cu-Zn producer (the Bolivar Mine), exploration concessions adjacent to the Bolivar Mine, and a new camp at the mine that supports mining, exploration and maintenance. From 1980 to 2000, former operators extracted approximately 300,000 tonnes of ore that was hand sorted to an average grade of 5-6% Cu and 25-30% Zn. From 2005-2010, Dia Bras produced from the mine just over 600,000 tonnes at an average grade of 1.7% Cu and 8.6% Zn. Dia Bras transported mineralized rock 275 km by truck and rail to its Malpaso mill, located about 30 km west of Cuauhtémoc in central Chihuahua, from 2005 until October 2011 when the new Piedras Verde mill was commissioned only 5 km from the mine. (Note: the Company cannot use the term ?ore? because it has never completed a feasibility study.)

Jan 1, 2012

By A. Whillier

The decisive action taken by mine managements in recent years has been the main factor in bringing about the present downward trend in mine fires. A better understanding of the fundamental factors that govern the ignition and spread of fires. obtained as a result of investigations into mine fires, has provided useful guidance to production personnel. Similar investigations into fire-fighting techniques have assisted the Rescue Training Service and mines to institute more effective fire-fighting techniques. Some of the more important findings of recent investigations in these areas are outlined.

Jan 1, 1981