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By J. E. Murphy

The Bureau of Mines demonstrated ferric chloride leaching of galena concentrate on a continuous bench-scale basis. Leaching was performed at 95° C and with a contact time of 15 min. The ferric chloride leaching solution was continuously fed to a leaching tank at a constant rate for periods up to 45 h. In each test a constant redox potential was maintained in the slurry exiting the leaching tank by controlling the concentrate feed rate. In the 45-h test, lead extraction exceeded 99.5 pct, and the lead chloride produced was 99.97 pct pure.

Jan 1, 1984

By Thomas A. Gwynn

"A beautiful America will require the effort of government at every level, of business, and of private groups. Above all it will require the concern and action of individual citizens, alert to danger, determined to improve the quality of their surroundings, resisting blight, demanding and building beauty for themselves and their children." "Improvement of our environment" has become a cause much like "motherhood". The increased awareness of the public concerning this subject makes it most unpopular for anyone to be involved in anything that seemingly is detrimental to our environment. And this awarement goes far beyond our biggest pollution problem in America - the distribution of paper, abandoned automobiles, beer cans and other garbage by our enlightened society along every city, highway, trout stream, river and mountain in America. In fact, the greatest awarement comes because of the "sensational" reporting and writing in our various national communication media, wherein the same voting citizens who so generously distribute their refuse about the countryside are emotionally aroused and duped into transferring what is truly a national problem onto the shoulders of a few industries - notably and particularly the mineral extraction industry. Certainly mankind is more and more stumbling over his own garbage daily, a fact that is easier to sell a citizen of one of our large cities than a resident of the wide open spaces of the west. Yet even in the Rocky Mountain states, the "Land of Sky Blue Waters", the "Big Sky Country", and particularly in Salt Lake valley smog is not unknown. Pollution and littering have become problems that need to be faced squarely. In North Dakota alone it has been estimated that one section of farm land each year flows down the mighty Missouri and the greatest producer of sediment is now reported to be the highway department.

Jan 1, 1969

By Susanne Pignolet

Ore microscopy has been applied to the complex lead-zinc-copper-cobalt-nickel ores from the Madison Mire in the Fredericktown subdistrict of the Southeast Missouri Lead District to predict potential beneficiation problems. It has been found that in some portions of the ore deposits, textures are present which may result in metal losses. In ores from the Bonneterre Transition Zone the intimate association of siegenite with chalcopyrite may result in cobalt and nickel losses to the copper concentrate. In ores from higher stratigraphic horizons, this association is relatively uncommon, and siegenite is commonly associated with bravoite. This latter association will increase the recovery of the cobalt and nickel in bravoite, even though some of the fine-grained bravoite will not be recoverable. Other textures which may result in potential beneficiation problems include coatings of covellite on chalcopyrite and inclusions of sphalerite in galena.

Jan 1, 1983

By G. E. Tooker

This paper (1) presents new data on the use of horizontal curves to optimize the alignment of belt conveyors. The operating concept of a horizontal curve is simple. As an element of the belt passes through the curve, it is motivated to drift toward the center of the curve by unbalanced tension forces in the belt. This lateral drift is resisted by the forces of friction and gravity, which in turn can be stated as a function of drift. Resisting forces, as a function of drift, are stated in terms of variables such as the amount of load on the belt, and parameters such as the trough angle, tilt angle, and super elevation angle, and number of rolls in the idler. The trick is to determine that the belt will drift to a position of equilibrium within predictable limits, without physically constraining the edge of the belt. In practice this prediction is not easy to make without the aid of a computer. The motivating force is easy to calculate, but its value is continually changing throughout the angle subtended by the curve arc. The resisting forces are constant throughout the curve for a given drift and load condition, but the calculations are very complex. Data in this paper will assist the conveyor designer in making preliminary calculations for horizontal curves. Presented is the equation for calculating the motivating force, and a family of curves that show the resisting force as a function of lateral drift for some commonly encountered conveyor design criteria.

Jan 1, 1985

By Wilbur J. Morin

Construction of Flaming Gorge Dam in northeastern Utah necessitated the construction of a new state highway, Utah-260, to provide access to the dam and the town of Dutch John. A 550-foot arch structure was designed to span Cart Creek, about one mile southwest of the dam. The rock exposed at the site is highly fractured quartzitic sandstone with interbedded shale of the Precambrian Uinta Mountain Group. Eight exploratory holes were drilled, four in each abutment area, to determine rock types, the extent of fracturing at depth and rock strength. Drill cores in the west abutment revealed blocks of quartzitic sandstone loosened by the weathering and partial removal of underlying shale beds. The rock in the east abutment area was found to be highly fractured to depths of 70 feet and as far east as 50 feet from the footing locations. Selected core sections were tested for unconfined compressive strength but the values were not considered-representative of the in-situ fractured rock. To prevent movement along or, perpendicular to open fractures, four drilled-in columns were provided at the base of each footing. These extended 50, feet beyond the base of the footing, along the bearing and inclination of the thrust reaction.

Jan 1, 1963

By Valerio Violo, Antonio Raschilla, George Kafantaris

"The Cityringen project in Copenhagen, Denmark will form a new circular line in the city center and will consist of 21 new stations (17 + four transfer stations) and approximately 31 km (19 miles) of earth pressure balance (EPB) twin-bored tunnels.The new tunnels passed under the historical building of Magasin du Nord, McDonald’s and two pubs in the heart of the city with a minimum cover of about 4 m (13 ft).To minimize the movements, a complex system of compensation grouting and jet grouting soil treatment was performed. A detailed action plan between the parties involved allowed coping with the critical tunnel boring machine’s (TBM) successful passage.The Cityringen is an extension of the existing metro line underground Copenhagen and will include the City Circle Line, 15 km (9.5 miles) of twin tunnels looping around the city. The City Circle Line will form a new circular track inside the city center and will intersect the existing M1 and M2 lines at Kongens Nytorv and Frederiksberg stations, as well as suburban train services at København H, Østerport and Nørrebro. It will extend the Metro network to the Nørrebro, Østerbro areas and the central station at København H (Fig.1). The two new lines M3 and M4 will run on the same tracks, but the M3 will be a circle route running around the entire line, whereas the M4 will drive from the station to the north side of the city.The €1.5 billion design-build contract was awarded by Metroselskabet in January 2011 to the Copenhagen Metro Team (CMT), a joint venture (JV) between the Italian companies Salini, Tecnimont Civil construction and Seli SpA. Since the bankruptcy of Seli SpA and Tecnimont, Salini Impregilo now owns 100 percent of the JV shares. Seli Tunneling Denmark ApS, a subcontractor to CMT, was initially constituted as a Seli SpA subsidiary and, following the economic difficulties of Seli SpA, was acquired in 2015 by Salini Impregilo. Seli Denmark is in charge of the tunnels excavation and lining and owns the four 5.84-m (19-ft) diameter Seli/Kawasaki earth pressure balance machines."

Jan 5, 2017

By T. Krumins, L. Zunti, R. Frischmuth

"Titanium and titanium alloys are commonly selected for pressure oxidation autoclave vent piping and pressure control valve components, as well as autoclave internals and other process piping. In the autoclave vent application, titanium ignition risk is controlled by limiting oxygen concentration, and preventing high gas velocity gas impingement on surfaces. Oxygen concentration is dependent on the autoclave pressure and temperature operating conditions and therefore oxygen concentration and the associated titanium ignition risk is dependent on standard operating procedures, process control interlocks and permissive conditions. It is not uncommon for these standard controls to be deficient during atypical operating conditions, or for operations to deviate from the operating procedures, increasing the potential for a titanium ignition incident. Titanium ignition risk caused by elevated oxygen concentration in autoclave vent systems can be reduced with the introduction of an online autoclave overpressure calculation and the configuration of associated interlocks and permissive conditions. INTRODUCTION High temperature pressure oxidation (>190°C) is a well recognized and versatile metallurgical oxidative pre-treatment process commonly used to liberate gold from refractory sulphide ores and concentrates before conventional leaching with cyanide. Titanium and titanium alloys are highly corrosion resistant in pressure oxidation process conditions and are therefore commonly selected as materials of construction for many components including: autoclave internals, agitators, process piping, and components in autoclave vent systems. Operations that anticipate or have experienced aggressive corrosion in the vent system often have little choice in material selection other than the use of titanium (Krag & Henson, 1992). Titanium is not suitable for use with elevated oxygen concentrations and is considered a restricted material because of its high pyrophoricity and combustion propagation properties (Beeson, Smith, Stewart, 2007). Several serious incidents have occurred in which titanium materials have ignited in autoclave applications (Zawierucha, McIllroy, Million, 1995). In autoclave vent applications, titanium ignition risk is reduced by preventing elevated oxygen concentrations, maintaining low gas velocities, and minimizing the potential for gas impingement on surfaces. Oxygen concentration in the autoclave vapour phase and vent system is dependent on the autoclave operating pressure and temperature conditions and therefore titanium ignition prevention controls typically include process interlocks and operating procedures based on the selected nominal design operating conditions. However, it is not uncommon for these controls to be deficient or for operations to deviate from the nominal operating conditions over time, increasing the risk of titanium ignition. The introduction of an online calculation of autoclave overpressure and a maximum target autoclave pressure as well as associated process control interlocks and permissive conditions can alert the autoclave control room operator and prevent an elevated oxygen concentration from developing, and therefore reduce titanium ignition risk in autoclave vent systems."

Jan 1, 2016

By Milton Hood

The Copper Flat Property is located approximately 6 miles NE of the small town of Hillsboro in Sierra County, N. M. (Fig. 1). Hillsboro was the center of considerable mining activity in the late 1800's and early 1900's following the discover, of gold bearing vein deposits and later discovery of, placer gold along the east slopes of the Animas Hills. The Copper Flat orebody is a porphyry type deposit occurring in a small quartz monzonite porphyry stock that has intruded the center of a circular andesite plug (Fig. 2). The primary ore mineral is chalcopyrite. By-product values are contained in gold, silver and molybdenum.

Jan 1, 1983

By Robert H. Raring

Viewed abstractly, a mill may be defined as a mineral processing facility located somewhere between the mine and the tailings storage area, Just how mining operations and the demands of tailings storage affect mill design is, the subject of this paper. At the outset, it will be readily acknowledged that no two installations can, or ever will be the same. At one extreme is the bucket line dredge where the distance between the ?mine? and the tailings area is measured in terms of tens of feet. At the other extreme, the large open pit copper mines are frequently spread across twenty, miles or so of countryside with the ore moving to the mill, as exemplified by the operations at Bingham Canyon, Ray, or Ruth - the "upstream" counterparts of Garfield, Hayden and McGill. In each of these cases, mill location was largely determined by requirements for tailings storage and/or water supply.

Jan 1, 1961

By H. E. Rutherford

Monterey Coal Company has begun a geologic monitoring program in order to better understand our in-mine geologic conditions and to apply the knowledge gained to our mining operations. Two methods are used to collect information. The first is a monthly examination of conditions throughout the mine using a rapid mapping technique. The second is the detailed mapping of specific events encountered during mining such as faults and roof falls. The data gathered from both methods is correlated with operational statistics to create a geologic/production database. From the database, a monthly evaluation of mining conditions is made. Also, the database has proved useful in such areas as forecasting roof conditions and examining how faulting has affected mining operations.

Jan 1, 1984

By R. A. Burns

The production of kaolin and calcium carbonate in North America exceeds 13 million tons sold into higher value market segments. With a few exceptions, the markets supplied exhibit mature growth rates. In some market sectors, technology changes have and continue to occur shifting pigment-type consumption and growth. New sources of supply will impact current businesses. New product and process developments for kaolin and calcium carbonates are continuing. Each of these issues is examined in developing a view of the future for kaolin and calcium carbonate in North America.

Jan 1, 1997

By Claus Becker

The Mixshield is a tunnelling machine for water bearing soft soils. Developed on the basis of the Hydroshield, it extents the application of this machine to cohesive soils. The design of the drum-type machine allows three different applications 1. As shield with liquid supported face and hydraulical mucking 2. As Compressed-Air-Shield 3. As Earth pressure balanced shield. The Mixshield is employed on three big contracts 1. a 6.3 km ring tunnel in Hamburg, outer diameter 5.95 m, with a new developed segmented concrete lining 2. a 1.9 km pipe-jack job near Cologne, o.d. 3.6 m 3. Metro Lot 3 in Lille/France, o.d. 7.7 m, 3.2 km long with segmented concrete lining and a most sophisticated separation-plant The site experiences will be reported.

Jan 1, 1987

Bioleaching of solid wastes lithium ion battery industries was carried out in this investigation. A new method for recovery of cobalt, potentially the basis of an economic and environmentally friendly process was examined. The present study was conducted using chemolithotrophic and acidophilic bacteria Acidithiobacillus ferrooxidans and some mixed thiobacilli collected from abandoned mine drainage. These organisms were able to utilize sulfur and ferrous ion as energy source. Bio-dissolution of cobalt was found to be faster than lithium. The effect of initial Fe(II) concentration, initial pH and solid/liquid (w/v) ratio were studied in detail. With increase of time of leaching the dissolution of cobalt was found to be increased and this must be due to competitiveness of the mixed thiobacilli for utilizing the energy source among them. Since the bacteria are belonging to acidophilic group the higher pH studies revealed a decrease trend in metal dissolution. Higher solid/liquid ratio also found to be detrimental for the bacterial activity. It seems bacteria are not resistant to higher concentration of the metal. The optimized conditions for bio-dissolution were sol-id/liquid (w/v) ratio - 10 g/L, initial Fe(II) concentration - 5 g/L, elemental sulfur - 1% (w/v). In the optimized conditions, cobalt dissolution was observed to be about 75 % whereas that of lithium was 15% after 25 days.

Jan 1, 2006

By Francois E. Heuze

We demonstrate a new capability to analyze the behavior of circular shafts in jointed rock. This was made possible by the development of a new, axisymmetric, joint finite element (2). Whereas the only previously reported such element was singular (1) and inadequate at some orientations, the current element has been extensively validated (3). The need for including discontinuities in a shaft analysis comes from two sources. First, the various rock formations may have discrete jointing, bed- ding, and interface between them. Second, there is a joint at the boundary between a concrete liner and the rock, and possibly between the various segments of the concrete liner. To demonstrate the applicability of the new model, we analyze a vertical circular shaft 5.4 m in diameter, in a series of horizontally bedded sandstones and siltstones. The shaft excavation is followed through three initial steps: 6 m, 15 m and 24 m deep.

Jan 1, 1979

By E. J. Wasp

An upsurge of interest in slurry pipelines to move coal from Wyoming, Montana, and Colorado to markets in the southwest, west, midwest and northwest has recently developed. Specific pipelines have been proposed to serve these markets; the routes of these lines are depicted in Exhibit I. It is, therefore, timely to discuss some technical aspects of the terminal facilities for these western coal pipelines. The discussion will be based on experience with the Ohio and Black Mesa pipelines as well as detailed planning and testing for a proposed 1,000-mile system from Wyoming to the middle south area. The economics of the pipeline terminal processes are heavily depend¬ent on site, type of process used, and other specifics of the situation. However, the following approximate breakdown of costs for a 1,000 mile, large capacity pipeline will be useful for orientation purposes. [Water supply 4 Coal cleaning 5 Feed preparation 10 Slurry transportation 72 Dewatering terminal 9 100%]

Jan 1, 1976

By Robert W. Gordon

The art of excavating tunnels with continuous, full-face boring machines began almost 90 years ago, in the early 1880's. At this time, Colonel Beaumont designed and manufactured a seven-foot diameter tunneler for boring under the English Channel, Despite the absence of modern materials and manufacturing techniques, Beaumont's tunneler, powered by compressed air piped in from the surface, was quite successful. During its short, but impressive existence, this machine set a record of advancing in chalk 50 feet per day for 53 days - which is impressive even by today's standards. Despite the apparent success of this early tunneler, almost 80 years passed before any further significant development was accomplished in this field. Demands from the construction and mining industry and society itself have motivated the development of the modern tunneling machine. Our rapidly growing civilization needs faster, less expensive and safer means of excavating tunnels. Space age technology and materials have played a major role in making hardrock tunneling machines possible.

Jan 1, 1970

A Mark IV surface force apparatus (SFA) was used to conduct direct force measurements between mica surfaces in dodecylamine hydrogen chloride collector solutions at varying pH levels. It was found that long-range hydrophobic forces reach a maximum at pH 9.5, which also corresponds to the maxima attained by the contact angle and flotation recovery of quartz. The charge densities are comparable on both mica and quartz surfaces (0.40 to 0.48 nm2), making it possible to draw conclusions on the flotation of quartz from the direct force measurements conducted on mica. Therefore, it may be suggested that, in the pH range of 8.0 to 10.3, the maximum flotation recovery of quartz may be attributed to the appearance of a long-range hydrophobic force, which, in turn, can be related to the formation of a close-packed monolayer (or hemimicelle) in the presence of neutral amines formed as a result of hydrolysis.

Jan 1, 1998

By J. S. Lewis

Beneficiation and physical and chemical processing of non-terrestrial materials borrow strongly from terrestrial experience, but also involve the necessity of handling literally un-Earthly feedstocks, reagents, and environmental conditions. The present state of scientific and engineering understanding of the processing of non-terrestrial minerals, gases and hydrocarbons is reviewed with the production of rocket propellants, life-support fluids, structural metals, and refractories as the goal.

Jan 1, 1992

By C. A. Born

AMAX Inc. climax's mine-mill complex at Climax, Colorado is best known for its molybdenite production: 50,000 TPY of molybdenite flotation concentrate (95% MoS2) from mill heads containing 0.35% molybdenite. Less recognized are the byproducts that are concentrated from the tails generated in the rougher flotation circuit (see Figure 1). Climax recovers a heavy mineral concentrate by passing the rougher tailings from molybdenite flotation over Humphrey spirals (Figure 2a). This concentrate is floated using xanthate at pH 4 to remove sulfides, principally pyrite. The tails from the pyrite float are then cleaned of quartz, feldspar and light minerals by tabling (Figure 2b). Amine flotation follows at pH 1.5 and 75°C to float monazite (Figure 2c). The present circuit at Climax dries the monazite flotation tailings and utilizes high intensity cross-belt magnetic separation Figure 2d) to generate a high grade wolframite concentrate and a low-grade cassiterite product, both of which are contaminated with the mineral brannerite, (UO, TiO, UO2)TiO3. The uranium specifications have recently become difficult to meet due to the increasing percentage of brannerite reporting in the mill feed. A plant is being built utilizing hot sulfuric acid and sodium chlorate to leach this uranium from the monazite flotation tailings prior to their being fed to the wolframite- cassiterite magnetic separators. This modification is the subject of our paper.

Jan 1, 1975

By Reed J. Irvine

One normally does not find sudden and dramatic changes in the investment climate, barring the unexpected outbreak of-wars or revolutions. Asia has seen a fair amount of military action and revolt during the past year, not all of it unexpected There was the fighting in Laos, which resulted in the as yet unconcluded negotiations which will probably lead to the establishment of a neutralist regime. In April of 1961 another revolution occurred in South Korea, and the elected government was replaced by a military dictatorship.. Communist guerrilla activity in South Vietnam was stepped up, and uncertainty about the future of that area increased. Relations between Pakistan and Afghanistan became more strained, and while no fighting has broken out, diplomatic relations between the two countries were broken off. India was both the victim of further incursions of her territory by communist China and the perpetrator of the forcible seizure of territory from Portugal. Indonesia has been making preparations for an armed attack on the Dutch in New Guinea.

Jan 1, 1962