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By W. K. Cunningham, Edwin A. Gee

"INTRODUCTION This paper is one of many reporting on various aspects of the Bureau of Mines program during World War II directed toward alleviation of shortages in certain critical minerals some of these papers are published as technical papers information circulars, and reports of investigations, of the Bureau of Mines or in technical journals.The investigation described in this report was begun as part of the Bureau, of Mines program to develop acid processes for the extraction of alumina from low-grade bauxites and clays. A domestic shortage of high-grade bauxite suitable for treatment by the Bayer process became acute as a result of World War II; and intensive search for a practical acid process using lower-grade alumina-bearing raw materials was therefore warranted.A survey of the various methods for extraction of alumina from clay has been presented in an early Bureau of Mines publication. 4/ The principal barrier to the successful operation of an acid process has been the difficulty experienced in developing a suitable commercial method for purifying the crude aluminum salts after the clay extraction is complete. Iron salts are the foremost contamination influence. A review of the more prominent procedures that have been proposed for separating iron and aluminum salts can be found in the well-known text on aluminum by Edwards, Frary, and Jeffries. 5/The majority of acid processes to extract alumina from clay employ sulfuric acid as the leaching agent, and the purification is thus reduced to the separation of iron and aluminum, sulfates."

Feb 1, 1948

By Kazimierz Gwizdala

In recent years, in Poland the ATLAS piles have been successfully applied for some constructions near Gdansk. The piles have been used as foundations for housing and another areas of civil engineering, in delta Vistula geotechnical region, characterized by weak, highly compressible soils represented by mud and peat, lying in sub-surface layers, several meters thick. Usually below are dense sandy soils or gravel. In all cases, the base of ATLAS piles rested on sandy soils. The analysis of pile bearing capacity has been discussed and verified by static pile load tests (SPLT). The load-settlements characteristics obtained were satisfactory. In the paper, the results of geotechnical investigations as well as calculations and load tests are shown. The ecological aspects of ATLAS piles application within highly urban areas of the cities and complex geotechnical conditions are emphasized.

Jan 1, 2006

By P. Miranda, K. Le, G. Maes, R. Peters

"The Mount Milligan Mine, owned by Thompson Creek Metals Company Inc. (TCM), started operations in September of 2013. It is located between the communities of Fort St. James and Mackenzie and is the first major metal mine to open in British Columbia in 15 years. Based on reserves as of January 1, 2014, it has an estimated 22 year mine life with 2.1 billion pounds of copper and 6 million ounces of gold in reserves. Like all commissioning operations, there have been issues achieving design throughput and recovery due to flow sheet design, equipment failures, control philosophy, and reagent scheme. Efforts to improve overall mill performance include equipment modifications, reagent screening and testing, and grind size testing. Applying these changes to the mill and working closely with the mine has resulted in continuous improvement each month as Mount Milligan looks to achieve the nominal design capacity of 60,000 dry metric tonnes per day in the later part of 2015. Considerable focus is being placed into ensuring size reduction equipment is utilized effectively. Additional modifications and tests are being undertaken to steadily improve processes and alleviate restrictions in the mill. This paper will discuss the start-up and present ramp-up history of Mount Milligan, the current mill processes, and the steps taken to achieve expected production numbers.OPERATION BACKGROUNDMount Milligan is an open-pit copper and gold operation wholly owned and operated by Thompson Creek Metals. It is located approximately 155km northwest of Prince George, British Columbia, between the communities of Mackenzie and Fort St. James. The copper-gold porphyry deposit contains a Measured and Indicated Mineral Resource of 706.7 Mt at 0.18% Cu and 0.33 g/t Au, containing 2.84 billion lb. copper and 7.50 million oz. gold. Mine life is currently estimated at 22.1 years (“Feasibility Update – Mt. Milligan,” 2009). The mill is designed to process 60,000 dry metric tonnes per day and produce 400 dry metric tonnes of concentrate per day averaging 25.5% Cu and 40 ppm Au. Concentrate is delivered by truck and trailer to Mackenzie followed by rail to Vancouver for overseas shipping to various customers.Mount Milligan is considered a “zero discharge” operation meaning no process or surface water will be discharged to the environment. As well, stockpiling is very limited and is only permitted for a short period of time. This scenario presents several unique challenges. Scheduling of ore/waste production must be carefully planned as waste rock is used to build the tailings storage facility (TSF). Reagent selection is also important as persistent chemicals will have a tendency to build up in reclaim water which feeds the process water tank."

Jan 1, 2015

By Edwards A. B

A table concentrate obtained experimentally by the New Occidental Gold Mines N.L. has unusual interest on account of the presence in it of abundant coated or "black" gold. The concentrate was obtained from ore from the New Cobar mine, Cobar, New South Wales, by feeding the oversize product from a "Dorr Bowl classifier to a Card table.Its assay value was 129 oz. of gold and 52 oz. of silver per ton, yet practically no free gold could be seen on panning.When, however, the concentrate was digested in hydrochloric acid fine rusty gold could be obtained by panning.The following chemical analysis was carried out by the mining company on a similar sample of concentrate.

Jan 1, 1941

By Konstantinos Modis

According to recently established theoretical analysis and under certain conditions, a critical sampling density can be determined for an earth-related space-distributed natural variable. Sampling above this critical limit adds little to the mapping results. The objective of this paper is the application of the above theory to the Sesklo clay quarry in Greece, where Heracles General Cement Company had conducted a sampling campaign to estimate its reserves. The structural analysis of Al2O3 values generated a variogram model, from which the critical sampling density was identified. This critical number was by far lower than the existing sampling density. Clay reserves were then estimated using geostatistics and inverse distance squares in different data schemes with variable densities. The results of the comparisons between the various models revealed that, when the sampling density was greater than its critical value, geostatistics and deterministic interpolation gave similar estimations, which is also in agreement to the theory. The optimal sampling grid finally proposed here, will result to significant cost savings in the next drilling program which is now in plan by the company.

Oct 1, 2009

By W. P. Johnstone

The computer assisted generation of geological models to represent the geometry of, and grade distribution within, orebodies is a rapidly growing area of the geological profession. Such models are increasingly used as a necessary starting point in determining the mineability of mineral deposits in terms of practical mine design and economic considerations. The transition from traditional techniques such as field or underground mapping and the manual calculation of grade and tonnage estimates, as well as related activities such as the interpolation of cross-sections, the use of stereographic projections, core logging and hand contouring, to computerized applications, is by no means complete. In fact, many geological professionals deliberately avoid the use of computer simulations based on the perception that the resulting models are simplistic and that their construction is not founded on sound geological principles. The purpose of this paper is to assess current thinking on this topic by considering; (a) an overview of advances in the drafting of geological maps, (b) the theoretical basis for multi-dimensional geological modelling, (c) the case for combining traditional and modern techniques, and (d) the benefits to the mining value chain.

Jan 1, 2003

By W. H. Langer

At the start of the 20th century Denver?s population was 203,795. Most streets were unpaved. Buildings were constructed of wood frame or masonry. Transport was by horse-drawn-wagon or rail. Statewide, aggregate consumption was less than 0.25 metric tons per person per year. One hundred years later Denver had a population of 2,365,345. Today Denver is a major metropolitan area at the crossroads of two interstates, home to a new international airport, and in the process of expanding its light rail transit system. The skyline is punctuated with skyscrapers. The urban center is surrounded with edge cities. These changes required huge amounts of aggregate. Statewide, aggregate consumption increased 50 fold to over 13 metric tons per person per year. Denver has a large potential supply of aggregate, but sand and gravel quality decreases downstream from the mountain front and potential sources of crushed stone occur in areas prized for their scenic beauty. These issues, along with urban encroachment and citizen opposition, have complicated aggregate development and have paved a new path for future aggregate development including sustainable resource management and reclamation techniques.

Jan 1, 2009

By H. Meseck

The new building of the Central Bank of Iraq in Baghdad was footed in difficult underground conditions on more than 600 reinforced concrete driven piles, with cross-sectional diameters of 45 x 45 cm and pile lengths of 12.0 to 18.0 m. The necessary embedded depth and the bearing capacity thus reached were established on all 600 drives piles by means of dynamic pile tests. For the calibration of the dynamic pile tests, 6 static pile load tests were carried out. The execution of the construction and the results of the extensive tests on the building site are shown.

Jan 1, 1989

By Panshi Xie, Xicai Gao, Yi Luo, Youfu Zeng, Yongping Wu, Shenghu Luo

This research investigates roof deformation and failure characteristics, as well as mechanical interaction between the panels of the roof strata above two adjacent working faces in a steeply inclined coal seam. Physical modeling with photogrammetry measurement method has been employed in this investigation. The movement of roof strata and section pillar, as well as the stratum morphological characteristics, was quantitatively analyzed. Results show that the roof movement direction above the two panels has zoning characteristics, especially in the lower panel. Roof migration in the lower panel of the working face is larger than that in the upper panel. The roof to floor closure perpendicular to the seam direction is larger than the sliding along the seam. The maximum roof concave and convex bending occurred at the middle and upper parts of both panels; the roof bending in the upper panel mining area indicates a larger mining disturbance induced by lower panel mining. The void ratio contour of the lower panel is an asymmetrically arched shape, which is different from that of the upper panel area. The higher roof strata above the upper panel exhibit separation and breaking, whereas the lower roof exhibits compression due to mining in lower panel. The section pillar is compressed and slides slightly, which aggravates the mechanical interaction between the panels and increases the caving height of the roof over the lower panel and the periodic weighting intensity

By Panshi Xie, Xicai Gao, Yi Luo, Youfu Zeng, Yongping Wu, Shenghu Luo

This research investigates roof deformation and failure characteristics, as well as mechanical interaction between the panels of the roof strata above two adjacent working faces in a steeply inclined coal seam. Physical modeling with photogrammetry measurement method has been employed in this investigation. The movement of roof strata and section pillar, as well as the stratum morphological characteristics, was quantitatively analyzed. Results show that the roof movement direction above the two panels has zoning characteristics, especially in the lower panel. Roof migration in the lower panel of the working face is larger than that in the upper panel. The roof to floor closure perpendicular to the seam direction is larger than the sliding along the seam. The maximum roof concave and convex bending occurred at the middle and upper parts of both panels; the roof bending in the upper panel mining area indicates a larger mining disturbance induced by lower panel mining. The void ratio contour of the lower panel is an asymmetrically arched shape, which is different from that of the upper panel area. The higher roof strata above the upper panel exhibit separation and breaking, whereas the lower roof exhibits compression due to mining in lower panel. The section pillar is compressed and slides slightly, which aggravates the mechanical interaction between the panels and increases the caving height of the roof over the lower panel and the periodic weighting intensity

By Andy Fortin, Jeet Basi, Simon Hille

Goldcorp’s Eleonore mine is situated in Ell Lake area in the northeastern part of the Opinaca reservoir in the James Bay region of Quebec. The design of the 7000 t/d process plant includes crushing, grinding, bulk sulphide flotation, separate concentrate and tails leaching and detoxification circuits and residue handling. Detoxified flotation tails are thickened and filtered. A portion of the filtered tails are blended with the thickened detoxified sulphide concentration for paste backfill. The remaining filtered tails are trucked to the waste management facility. This presentation will describe the challenges faced with the commissioning and subsequent ramp-up of the flotation tails filter plant and the successes achieved by the multi-discipline team at Eleonore.

Jan 1, 2016

By Stephen T. Young

The construction of Phase 2 of Hong Kong Station, its retail podium and International Finance Centre Two, the tallest building in Hong Kong, will be completed in the middle of 2003. This paper describes the design and construction of the slurry wall for the Station (both Phase 1 and Phase 2) and the two commercial buildings at the Station. The slurry wall is used as the permanent earth support wall for the station box and the excavation depth ranges from 70 feet to 120 feet. Top-down construction technique was adopted to support the excavation of the station, while circular cofferdams relying on hoop stiffness were constructed to support the basement excavation of the two towers. The designed behavior of the slurry wall is also compared to the as built behavior.

Jan 1, 2003

By A B. Phillips

This paper details the approach adopted to upgrade the current metallurgical facilities at both the Driefontein and Kloof Gold Mines in the Republic of South Africa. Goldfields Ltd operates eight metallurgical plants within South Africa of which three have recently been upgraded to replace the older technology previously installed, with modern equipment. This upgrade was undertaken with a view to improving extraction efficiencies and to reduce operating costs. The upgrade was undertaken in a phased approach with the first phase focused on the replacement of the filtration/zinc precipitation processes with modern pumpcell carbon-in-pulp technology. Included in this upgrade phase was the installation of an automated hands-free electrowinning cell, which represents the first commercial application of its kind in the industry. The second phase of the upgrade entailed replacement of the multiple comminution stages previously installed with large SAG and SAG/Ball mill combinations. Due to the rapid return on these projects, a fast-track approach was adopted which necessitated the purchase of available good conditioned second-hand mills from both within South Africa as well as in Australia. Goldfields Ltd is a large mining house with gold mining operations in South Africa, Australia and Ghana. A well advanced PGM exploration project is underway in Finland- Arctic Platinum.

Jan 1, 2003

By Edward J. Cording, William H. Hansmire

INTRODUCTION The Washington Metro, a rapid transit system that will serve the District of Columbia, Virginia, and Maryland, has been under construction for about two years. Construction of the Metro by the Washington Metropolitan Area Transit Authority involves a large amount of cut and cover, soil tunnel, and rock tunnel construction. To aid initial construction and improve future designs, performance observations were undertaken on tunnels in the initial construction phase. The University of Illinois Department of Civil Engineering was engaged to carry out a comprehensive program of field observations and measurements for this purpose. One part of the program was on the first soft ground tunnel constructed in the system. The tunnel is a 2200-ft (670 m) twin-bore section, designated Contract A-2, in downtown Washington. Two objectives of this program were to determine the relationship of construction procedure to settlements and to observe the pattern of soil movement around the tunnel as an aid in evaluating underpinning criteria for nearby structures. A test section, consisting t three instrument lines located across the tunnel path, was established prior to mining in Lafayette Park to measure in detail both vertical and lateral soil displacements as the tunnel was mined through the section. The site was selected because it is free from surface structures and access for installation and reading of the instruments was convenient. Load and distortion measurements on the lining were also made within the test section; observations of construction procedure were maintained throughout construction.

Jan 1, 1997

By WM. H. RINKENBACH, C. A. Taylor

No complete work on explosives, their constitution and analysis, has hitherto been published. Several books that contain chapte.r;s on analysis do not cover the matter thoroughly. Methods tha;t, manu~ facturers, testing stations, and other . agencies have developed to meet their own requirements have not been made public. The Bureau of Mines has issued four publications 1 - cov:eri:ng special phases of the subject. This bulletin. is not inte.nded to replace those reports, but rather to cover present methods employed 'in the , industry and to include all classes of explosives and the materials used in their manufacture. No sharp distinctions can be drawn between classes of explosives. . Surplus military explosives, for example, may be used for blasting, just as blasting explosives, under some conditions, may be employed for military purposes. Moreover, one class gradually merges into another because of similarity in composition. Explosives are here grouped as dynamites, black powders, propellants, detonators, and primers. Some materials are used in practically all these groups ; others in only one. To discuss all the materials that have been or that may be used and the methods for their identification and quantitative determination is not feasible, but the methods described will probably suggest ways of examining new mixtures.

Jan 1, 1923

By Jacob Chacko

The east span of the San Francisco-Oakland Bay Bridge (SFOBB), which is one of the most heavily traveled bridges in the world, will be replaced due to seismic safety concerns. The majority of the new bridge will be founded on large-diameter (1.8 to 2.5 meters), approximately 60- to 100-meter-long pile foundations The large-diameter steel pipe piles and soil conditions are similar to those used/encountered in many offshore structures. Thus, the design methods used are based on site-specific modifications to the procedures recommended by the American Petroleum Institute rather than the conventional procedures that have been formulated and used for the design of much smaller piles. Pile foundations will experience their maximum loads during the design earthquake. For the Safety Evaluation Earthquake, tension loads of up to approximately 80 to 90 meganewtons (MN) and compression loads of up to approximately 120 to 140 MN were calculated. Due to the economic importance of the SFOBB and the consequences of catastrophic failure in both economic and human terms, the design and analysis of the pile foundations supporting the bridge consider a number of aspects of pile-soil behavior that are normally ignored. Those aspects include: 1) the effects of consolidation and setup, 2) the behavior under dynamic loading, 3) the losses of resistance under cyclic loading, and 4) the load-settlement behavior of the piles under severe cyclic loading conditions. Since the treatment of complex aspects of pile foundation behavior is not codified in any guiding documents, several project-specific methods were developed for design and analysis of the foundation piles.

Jan 1, 2002

By T. P. Meloy

A methodology is presented for finding feasible or locally optimal designs in the class of homogeneous, countercurrent, processing networks performing two-component non-sharp separations. The advantage of the methodology developed here is that given a set of independent performance criteria (specifications such as network separation factor, beneficiation ratio or recovery), a feasible or locally optimal countercurrent network design meeting those criteria can be found in one step. In the methodology, graph-theory was used to explicitly obtain the exact network responses of specific countercurrent networks. These responses were used to formulate the linear recursion equations whose solution gives the expressions for the countercurrent network responses which are a function of the stage transfer functions for two-component, non-sharp separations. These expressions are also functions of the network variables n and c. These expressions, together with the set of independent design criteria, were solved simultaneously for n and c using the Levenberg-Marquardt algorithm for systems of constrained, non-linear equations. The network variables n and c embody the coded network design information which is used to find the feasible network design which satisfies the set of independent performance criteria.

Jan 1, 1994

By John E. Leitch

The cost of corrosion as measured by such cost components as the renovation or replacement of coated steel, or the use of expensive coating systems on steel, is considerable. Extrapolating from figures for the USA would place the overall cost of corrosion for South Africa as a figure of the order of magnitude of something over 1% of the GNP. This is a sizeable amount, of which costs associated with atmospheric corrosion would be a significant proportion. The corrosivity of an atmosphere can be defined as the ability of the atmosphere to cause corrosion in a given metal or alloy (International Standards Organization [1]). The ISO Standard 9223 specifies the key factors in the atmospheric corrosion of metals and alloys, and defines categories of corrosivity on the basis of these factors. Prior to the publication of that ISO standard, Callaghan published the results of his twenty-year exposure programme and his excellent corrosivity map of Southern Africa [2]. The present author published updates of the corrosivity map in 1999 [3] and again in 2003 [4]. The summary of the individual areas of corrosivity around Southern Africa was published in the latter paper, and is reproduced here as the following TABLE 1. Of significance in TABLE 1 are the numerous regions of very high corrosivity (C5 or beyond), particularly the rural West Coast shoreline, the North East Coast (KZN) shoreline, and the coastal cities Cape Town, Durban and Richards Bay. The corrosivity map as published is obviously based on much extrapolation as only a small number of points have been measured. During the past three years further measurements have been made, mostly however at the same sites in order to give greater reliability and to monitor long-term trends with changes in pollution. These two aspects are incorporated in this update. There has become available a greater amount of air pollution data for centres in South Africa than was the case some years ago. In this present paper the pollution data are used to extrapolate the corrosivity over areas where little or no direct corrosivity measurement has been made. This methodology is described in ISO 9223.

Jan 1, 2006

By Homor N. McDonald, G. Dale Coe, Will H. Coghill

"INTRODUCTION Sporadic beneficiation tests have been made on the Birmingham (Ala.) red iron ores for the last 55 years. Now, gravity-concentration plants are in operation, of tables are in use. A major problem, as seen by the present writers, is to obtain a coarser concentrate and add to the recovery without increasing the quantity of slime. The oily practicable solution found so far is to recover, by means of concentration (hydraulic) classifiers, the coarse concentrate normally lost in the table middling and, by a similar method, to recover middling particles from the table tailings The size and shape of the coarse concentrate Particles combine to cause them to report in the table middling rather than in the table concentrate. Similarly, mineral is lost in the tailing. Because of this, the nature of the ore, the deportment jerking table, plant tests on classifiers and tables, and the suitability of small concentration classifiers to treat table zonal middlings are discussed herein.The work was done by the Southern Experiment Station, Bureau of Mines, in cooperation with the University of Alabama, Tuscaloosa, Ala."

Jan 1, 1935

By Jouko L. Lehtonen

Sheet pile walls can be sealed watertightly using various methods. The objective of this paper is to introduce a new innovation comprising the use of continuous cement grouting during embedding. The method has been tested on a field test site and installation and permeability features have been observed and analyzed. Installation can be carried out using traditional sheet piling machinery, merely some additional grouting equipment is needed. Installation speed of grouted sheet piles corresponds to that of conventional embedding. The permeability of the tested method is satisfactory in applications where e.g. polluted soil or water has to be isolated from the surrounding environment. In addition, this method can be used for conventional retaining walls where very low permeability is required or for reduction of soil vibration, e.g. close to a railway embankment. The new method to grout simultaneously and continuously during embedding has been developed based on respective innovations on impact driven steel piles.

Jan 1, 2006