Search Documents

By Dan Swidrak, Bill Zietlow

Halfway through a 17,770-ft long stormwater tunnel, an 11-ft diameter TBM encountered a karst void below the Mississippi River in Missouri, resulting in significant inflow. It was decided that the TBM could not safely advance without external intervention. Low-mobility grout was pumped from the surface. A rescue shaft was constructed and a conventional tunnel with spiling support was mined back to the machine. The TBM was removed and a 14-ft diameter TBM equipped with probing drills was relaunched. Probing from the new TBM encountered one additional karst feature but the machine advanced after grouting and successfully completed the tunnel.

Jun 23, 2024

By R. Quintero

The HYL Direct Reduction Process was the first in the world to operate successfully at industrial scale. The results were so innovative and attractive that other steelmaking companies acquired licenses for the HYL Process. Now in its 40th year of commercial operation, the HYL process has evolved into a modem, highly efficient and economical technology -HYL III. The technology offers high productivity, minimum energy and water consumption, electricity co-generation, raw material flexibility, premium quality DRI/HBI, and is highly versatile for meeting the specific needs of each user. A historical review as well as recent developments and future plans are presented in this paper.

Jan 1, 1998

This paper summarizes the process development behind the design of three different types of paste fill plants at operating Canadian hard rock mines. Each application has a unique paste backfill mix and process which utilizes the materials economically available to the mine site. The different plants produce paste fill composed of base metal tailings, a blend of recovered disposal pond tailings fines and alluvial sand, gold ore tailings, and a blend of gold ore tailings and alluvial sand. This work has led to the joint development by Inco and GL&V Ontario of the compaction storage mechanism for the de-watering of mill tailings to a paste consistency.

Jan 1, 1994

By J. P. Allen

Cobalt, nickel, and manganese can be recovered quickly, cleanly, and selectively from cobalt-rich manganese crust by leaching in dilute acid solutions in the presence of hydrogen peroxide. Common selective precipitation methods can then be used to recover these metals from the leach liquor. The leaching reaction produces only oxygen as a byproduct, and the waste residue from leaching was tested and found to be non-hazardous under existing EPA specifications. The leaching process is effective in either fresh water or seawater. This research is a part of the Bureau of Mines program to identify the mineral resources of the Exclusive Economic Zone and devise methods for recovering their valuable components.

Jan 1, 1990

By Verya Nasri, Mehdi Bakhshi

The development of the Montreal metro extension Line 5 -Blue Line- toward the northeast are located between the existing Saint-Michel station and Anjou. It consists of 6-km long two-track tunnel, five new stations and six auxiliary structures. Most of the tunnel (5.5 km) will be excavated by a 9.6 m diameter shielded rock TBM and supported by a precast segmental lining system. TBM will be fitted for probing and preexcavation grouting to control water inflow into the tunnel during the excavation. This paper presents major design aspects of the TBM tunnel including alignment, geological condition, spaceproofing, precast segmental lining, and geotechnical instrumentation and monitoring.

Dec 1, 2022

By H. Sevim

In a recently developed long term open pit production planning model, the optimum plan is found by exhaustively searching through nested pits of maximum-metal contents. A more efficient, dynamic programming (DP) based search algorithm now replaces the exhaustive search algorithm which was requiring prohibitively long execution time in real life cases. The logic and the formulation of the newly developed search algorithm are illustrated through a small hypothetical case. A real life gold deposit is treated to demonstrate that the algorithm does indeed find the optimum production plan among all possible plans. A comparison, in terms of computational savings between the two algorithms is also given.

Jan 1, 1994

By Allan Rocas, Aswathy Sivaram, Daniel Cressman, Tatiana Chiesa

The City of Toronto plans to construct a 1,350 mm consolidation sewer along the East Don Roadway (EDR). The project includes installation of approximately 260 meter of 1,350 mm diameter concrete pressure pipe through microtunneling methods. The sewer alignment crosses underneath a busy 5-lane arterial road and then follows the very narrow East Don Roadway road allowance. This paper discusses the significant challenges overcome to design the Don Roadway sewer using slurry microtunneling methods through mixed face conditions below the groundwater table in a congested road allowance. A curved microtunnel was ultimately required to avoid conflicts with existing utilities, condominium tiebacks and a bridge structure.

Jun 13, 2023

By Arthur B. Cummins

It is appropriate to discuss diatomite at an AIME meeting in San Francisco. California has led the nation, and the world, in the production of diatomite products for more than 40 years. It appears that our State will maintain this position for a long time to come. Diatomite today ranks high in the list of California mineral commodities, with a total value since 1889 well in excess of $100 million. California's production has more than doubled since 1942. In 1959, the value of diatomite production in California is exceeded only by the following industrial mineral materials-borates, stone, sand and gravel and cement20,28. Also, not unimportant is the production of diatomite in each of our other Pacific Coast States, including Nevada. First, let us define diatomite. It is a sedimentary siliceous rock of organic origin, which consists mainly of the fossilized remains of diatoms. Diatoms are microscopic aquatic plants which have the capacity of precipitating silica bio-chemically so as to form a part of their organized structure. In the economic sense, we are not concerned with the numerous types of sedimentary materials which contain minor amounts of diatom residues, or with impure or highly indurated siliceous materials, which may have been formed from diatomite2. Diatomite (synonyms--diatomaceous earth, kieselgurO is a term generally restricted to material of such qualities as to be suitable for commercial uses. Diatomaceous silica is a designation which is best used to distinguish the basic component of diatomite, that is, the substance of the silica shell itself, and which is the major' constituent of beneficiated diatomite or processed diatomaceous products.

Jan 1, 1959

By Russell L. Cook

Stringent environmental regulations, which have limited the use of sludge ponds, coupled with the economic incentive to clean more 'coal or to add fine coal cleaning additions to existing preparation plants have increased the use of static thickeners in preparation plants. The Lamella Gravity Settler, sometimes de signated Lamella Thickener, is a shallow depth sedimentation device which has been applied in a variety of industrial process and wastewater control projects in place of the conventional raked thickeners. This paper presents the theory and design of the La-mella Thickener, as well as describing the operating results from several full scale installations in a variety of Appalachian preparation plants.

Jan 1, 1977

By L. L. M. Kadnuck

The U. S. Bureau of Mines studied the suitability of using flexible tendon cable supports as secondary roof supports at a western coal mine. The supports were installed in longwall tailgate entries and grouted into the mine roof. This paper quantifies how the use of cable supports can improve ventilation in underground airways. A mine ventilation simulator was used to model the changes in airway resistance and airflow and show potential for further ventilation improvements when cable supports are used. Model results indicated that cable support use translated to savings in air pressure around the longwall panel and increased airflow at the longwall face.

Jan 1, 1994

By Karin Bäppler

Mechanized tunnelling is undoubtedly one of the most innovative disciplines in the international construction industry. Technological progress in the planning and production of most modern infrastructure is constantly striving for new records on basis of highly specialized solutions and know-how. Humans and technology have accomplished excellent achievements over the past few years in varied, difficult terrain. New length records are being set with the 64 km long Brenner Base Tunnel and the HS2 Railway system currently under construction in Europe. Cities are building ever longer and more demanding sewer tunnels. The paper highlights some of the challenges, trends and innovations of long-distance tunnelling projects.

Dec 1, 2022

By Dan Ifrim, Andre Solecki

Tunneling could be a major challenge to tunneling contractors as tunneling operations can be seriously affected by the Tunnel Boring Machine (TBM) performance. Specifying the appropriate TBM methodology, selection of systems and features, is critical for managing tunnel risks and contribute to successful tunneling project. The paper analyzes tunneling records from the recently completed City of Toronto’s Ashbridges Bay Treatment Outfall tunnel project and underlines the righteous selection of the TBM type and associated TBM systems in achieving good advance rates during tunnelling and managing project risks. The paper intends to draw attention of a few aspects of TBM technical specification importance and highlight the lessons learned from this process.

Jun 13, 2023

By N. A. Abdel-Khalek

The objective of this investigation was to compare the results of counter-current flotation column versus conventional flotation cell for the cleaning of a sulphur ore and its discrete size fractions. The tests were carried out using diesel oil as a collector and alcohol as a frother. Generally, flotation column produced concentrates of higher grade. For example, the grade of a rougher concentrate for a given feed obtained with the column increased by 33% higher than that produced with the flotation cell. Such higher grade could not be obtained using conventional cell even after 3 cleaning stages. Moreover, the column gave superior results for flotation of fine and ultrafine particles.

Jan 1, 1991

By Terence P. McNulty

Gold-bearing outcrops were discovered in 1862 by Union soldiers garrisoned at Needles, CA, near the northwest corner of the future State of Arizona. Sporadic mining began several years later, but engineered shaft sinking and mill construction were not adopted at Oatman and the neighboring camp of Goldroad until about 1900. Geological interpretations in 1915 enabled major production during the next decade. In the late-1930s, USSR&M built a new mine and mill in Gold Road and the District flourished until closure by Federal Order L-208 in October 1942. For about a decade, Oatman’s mines were among the largest gold producers in the American West.

Feb 1, 2024

By A. M. Raichur

Flocculation of fine coal is usually accomplished with the addition of commercially available organic flocculants. Recently it has been shown that biopolymers derived from microorganisms can be used to flocculate coal. The biopolymers flocculate coal efficiently and render the coal surface hydrophobic. The increase in hydrophobicity can be utilized either to separate the coal flocs from mineral matter. It can also be used for reducing the moisture content of fine coal. In this regard, flocculation and settling tests of fine coal with biopolymers and synthetic flocculants was undertaken and the results are discussed here. Also, a transport model was developed for the time-dependent settling tests for fine coal.

Jan 1, 1996

By G. H. Sedahmed, S. A. Nosier, M. H. Abdel-Aziz, A. A. Mubarak, M. A. El-Naggar, E. G. Abdel-Aziz

The performance of a rotating fixed bed reactor in recovering copper from industrial waste solutions by cementation is studied under various conditions. The rotating fixed bed is made of stacked woven steel screens to take advantage of two features of screens: the ability to present large area per unit volume and their ability to promote high turbulence. Variables studied are initial CuSO4 concentration, bed rotation speed, mesh number of the screens and bed thickness. The presence of baffles was found to increase the rate of cementation. The data were correlated by a dimensionless mass transfer correlation suitable for the design and operation of large scale cementation reactors.

By R. G. Reddy

Solid state reduction of roast movat chromite ore with carbon was carried out as a function of C/FeO ratio and temperature in the range 800°C to 900°C by thermogravimetry analysis (TGA). A two stage mechanism, (1) the reduction of FeO present in Roast Movat with carbon monoxide; and (2) the regeneration of CO by the oxidation of carbon with CO2 was proposed. The rate controlling step is the carbon oxidation reaction. A kinetic equation, that of random nucleation, was proposed. The activation energy for the reduction was determined to be 55800 J/mole and is compared to those activation energies determined for other chromite ores.

Jan 1, 1998

Over the years, numerous studies have been conducted to characterize the floatability of coal pyrite. Unfortunately, many of the results obtained using isolated samples of coal pyrite are not directly applicable to actual coal flotation systems where liberation and entrainment may be the major factors affecting pyrite rejection. In this paper, the association of pyrite with other coal constituents is investigated, and the data are presented for feed and product streams obtained from release analysis tests. Release analysis is used to minimize the effects of entrainment. Particle distributions for each stream are presented as functions of size and composition in order to discern the behavior of free and composite particles.

Jan 1, 1992

By Pierre Dosmond

In ore mining technology, the loading and hauling operations are undoubtedly the area where the most spectacular progress has been made during the last twenty years. I shall draw some examples from the Eastern France iron ore mines which I how well and whose production of 62 million tons for 1962 and 1963 constitute a worthwhile experience worldwide. The iron ore deposits of Lorraine are of sedimentary origin. They contain many mineralized horizons with workable seams situated from 330 to 830 ft. in depth. The dip of these seams is generally less than six percent. Their thickness varies from 6 to 23 ft. All seams are not workable throughout the whole area of occurrence, but in some mines there are five mineable seams in the same vertical section, with from 5 to 20 ft. of barren ground intervening between them. The iron content of the mineral varies from 28 to 36 percent. Specific gravity of the ore is 156 lb. per cu. ft. m place and 100 lb. per cu. ft. blasted. Reserves of iron ore in the Lorraine region are estimated at six billion tons with an iron content of more than 28 percent. These mines operate by means of rooms and pillars process, with pillar robbing; the final recovery is very good and averages 90 percent. Some years back, competition from richer, imported ores incited these mines to make constant efforts to increase their productivity and reduce mining costs, thus placing them in a leading position in mining technology, as evidenced by the dramatic evolution of their output per manshift (Figure No. 1).

Jan 1, 1970

By D. S. Ramey

In-situ leaching of the oxidized copper mineral resource at the San Manuel mine has proven to be a technically and economically viable method of copper extraction. Although this leaching method has been modeled to predict future production capabilities, the expected magnitude of the ultimate recovery from any portion of the present mine is not fully understood. A closely controlled test has been designed, constructed, and is now operating to determine the rate and magnitude of copper recovery. The test, initiated in June 1992, is scheduled to operate for approximately 18 months. This paper presents an overview of the test design and current results.

Jan 1, 1993