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By Leonard Sugin

Recent changes in the field of ore and bulk commodity handling has forced a reevaluation of previously conceived notions. When vessels were small, and sources of raw material were reasonably close to areas of need, the role of the shipping terminal was of secondary importance. Now terminals must be built to take advantage of the economic benefits of the supercarriers. The shipping rates of the 80's will not be determined by the 60,000 DWT or even 150,000 ton capacity bulk carrier, but rather by the supercarriers in the 250,000 DWT class or larger. When the Suez Canal was closed, the shipping industry took a hard look at the economics of the large bulk carrier. Naval architects overcame the problems and successfully designed large supertankers, which today are plying the seas in excess of 350,000 DWT. Orders have been placed for tankers of 480,000 DWT. The shippers of dry bulk materials are now coming to similar conclusions about the economics of supercarriers. As of today, over 40 orders have been placed for vessels in the 250,000 DWT class, representing an investment of over 11/2 billion dollars, and many more are being considered. These vessels are being designed as combination ore/oil (0/0) or ore/bulk/oil (OBO's) carriers. The oil industry has seen the need for terminals which can accommodate these supertankers. The dry bulk shippers, and particularly ore shippers, must now act.

Jan 1, 1972

By Yang Zhao, Wanping Wang, Siqing Liu, Shuming Wen

"In China, most reserves of rich iron ores have now been depleted and sustainable development of low-grade iron ores has become a critical discussion topic in the mining industry today. The aim of this study was to evaluate the applicability of beneficiating a low-grade, hematite-magnetite ore (assaying 18.64% Fe) for subsequent utilization. In this study, process mineralogy and beneficiation of the ore were carried out in the laboratory. First, mineralogical investigation shows that the main metal minerals are hematite, magnetite and a little octahedrite that cannot be used at present, and the main gangue minerals include albite, quartz and ankerite. Based on the above, a combined process of magnetic separation and gravity concentration has been developed by using laboratory low- and high- intensity magnetic separators and a slimes shaking table, respectively. Factors affecting these separation methods are discussed, including process mineralogy on the tailings of the high-intensity separator, where the iron minerals were found to be finely disseminated in the gangue as inclusions. By applying a two-stage grinding step and a magnetic separation stage together with gravity concentration, a marketable iron concentrate assaying 60.79% Fe at a recovery of 60.23% can be obtained, when the feed assays 18.75%Fe, which provides some useful information for the sustainable use of low-grade iron ore.IntroductionIron is the world’s most commonly used metal. Steel, of which iron ore is the key ingredient, represents almost 95% of all metal used per year, primarily in structural engineering applications and for maritime purposes, automobiles and general industrial applications. By the end of 2009, the iron and steel production in China ranked the first in the world, and reached 0.567 and 0.537 billion tons, respectively. The domestic supply of iron ore was 0.88 billion tons and about 0.628 billion tons of iron ore were imported in 2009."

Jan 1, 2015

By Alexander Karim

This paper reviews the growth pattern in bauxite and alumina production, and primary aluminum smelting through 1980. Because the alumina and primary metal are intermediate products of the major integrated aluminum companies, it is not possible to determine their production costs. The costs indicated in this paper are order of magnitude costs based on published figures and the market price of these products. The conclusions in this paper indicate the general pattern of growth in the aluminum industry and are not meant to be a substitute for the feasibility and economic studies that are needed for individual bauxite mining, alumina refining and aluminum smelting projects.

Jan 1, 1968

By Tom B. Corry

INTRODUCTION Located approximately 48 km (30 miles) south of Dallas, Texas, use to be the site of the Superconducting Super Collider. For those of you unfamiliar with the project, this was a multi-billion dollar project taken on by the U.S. Government for the further advancement of technology, medicine, and science. Major components of the project consisted of a Linear Accelerator known as the LINAC; three accelerating rings known as the Low Energy Boosters (LEB), Medium Energy Booster (MEB) and the High Energy Booster (HEB); the East and West Campuses where the Inner Reactor Halls would have been located; and the 87 km (54 mile) main collider tunnel. Unfortunately, this all came to an end on December 6, 1993, with the termination of the project due to the Government's cancellation of funds. This paper will deal with the two of the underground contracts before the termination. These two contracts were the 1122 contract which ran from N25 to N40 and the 1130 contract which ran from N40 to N55. (See figure 1) The 1122 contract was awarded to us in July of 1992 and consisted of the excavation and support of six (6) shaft varying in diameter from 5.5 m (18 feet) to 8 m (26 feet) and ranging from 39.6 m (130 feet) to 61 m (200 feet) deep and the driving of approximately 13,100 m (.43,000 If.) of main collider tunnel. Our second contract, the 1130, was almost identical to our first

Jan 1, 1995

By Theodore Feldsher, Seung Han Kim, Mourad Attalla, John Roadifer, Chu-Chieh Jay Lin

Lifelines in seismic regions of the world seldom can escape crossing active faults. Cities in California have been mitigating this risk by constructing improved fault crossings. This paper discusses the analyses and design of the lining for a tunnel carrying a water conveyance pipeline through a fault that can potentially displace during a major earthquake event. The paper presents expected fault displacement, fault width and orientation respective to the tunnel, characterization of the ground surrounding the tunnel and its interaction with the lining, and performance required of the lining. Several other fault crossings will also be presented and discussed

Dec 1, 2022

By C. L. Coldren

Recently there has been much discussion of the use of pipelines for the long-distance transportation of solids. Many have come to recognize the economies inherent in pipeline transportation. The widespread movement of oil and gas at astonishingly low costs - a gallon of oil moves from Montana to New York for less than that for the delivery of a postcard - has spurred others to sturdy this mode of transportation. Most interested people are aware of the inherent advantages of pipelines - continuity and reliability of operations - low manpower requirements per ton mile - moderate capital costs per ton mile - low maintenance costs per ton mile - low operating costs per ton mile.

Jan 1, 1963

By C. J. Bise, P. Bucks

Central Appalachian coal reserves are a valuable natural resource in high demand, both domestically and internationally, justifying efforts to increase percentage recovery through pillaring. Unfortunately, the challenge associated with pillar extraction introduces additional safety risks during the activity. Although pillaring developed prior to mechanized mining, current technology and mining practices have made this form of mining highly modernized. However, current fatality trends suggest that work still needs to be done to control the residual risk that is not controlled by modern practices, such as those having a personnel-performance-based component. This paper investigates the application of modern coal pillaring techniques and will present a risk-management-based strategy that targets personnel-performance-based risk, in order to improve the ability of safety engineers, managers and trainers to provide training programs addressing the needs of pillaring sections.

Jan 1, 2012

By M. Spangler

FirstMiss Gold installed a supervisory control system based on Pavilion Technology's Process Insights neural network software and Oil System's PI data historian. The primary goal of the system was to control the acid preconditioning circuit. However, our first successful control loop was on the limestone feed rate to the neutralization circuit. The information gained by modeling these circuits and the better control provided by the system has resulted in reagent savings of over $80,000 per month.

Jan 1, 1995

By I. Mikov

Established in the 60-ies, the Zlatna Panega quarry is a cement raw materials quarry supplying 95% of the needs of the Zlatna Panega Cement Plant with limestone, marl and other silica-aluminates. The two major types of raw materials are formed by accordingly dipping strata of Upper Jurassic limestones and lower Cretaceous marls. Between them there is a ?transition-zone? or ?contact-zone? of a high-silica content layer, about 5-m thick, defined as ?flint? by investigations including spot sampling throughout the quarry. For many years this ?contact-zone? layer was neglected due its negligible thickness. Further, with the increasing demand on the quality of the raw materials feed to the Plant and the focus on variability of the chemical and mineralogical components, it was decided not to mine any of the parts of the quarry contaminated by this material, for about three years. The latter had an impact on the availability of operating benches that could result in a substantial decrease in the total recoverable re-serves of Zlatna Panega, particularly with respect to marls. There were considerations for resorting to a partial, selective excavation of the quarry pit with a reduced lifetime for the lime-stones and re-opening of an other (currently in-active) marl quarry at a distance of 6 Km from the Plant. The Quarry Team of the Zlatna Panega quarry was assigned to study the problem. The ?contact? layer was duly confirmed with systematic geological (including mineralogy) studies, statistical analysis of available data, surface sampling and shallow exploration drills, resulted into distinguishing a third type of reserves and their credible subsurface delineation by means of geological 3-D modeling and quarry design. A new quarry design was finally elaborated with a view of providing flexibility in mining, utilization of the total volume of all available reserves and maximizing the mine life of Zlatna Panega quarry. An industrial test took place in December 2005, by using the contaminated parts of the quarry (co-mining of the ?contact-zone? materials) at a contribution of 15-20% in the raw materials mix, as dictated by their contribution in the total recoverable resources of the quarry. The purpose was to investigate the viability of this solution ? in line with improved quarry planning ? without compromising the quality of cement production and the efficiency of Plant Operations. Results were overall successful.

Jan 1, 2006

By M. du Plessis, J. P. Gouvea

Mesh based areal support is commonly applied in South-African deep-level gold mines. It forms part of an integrated support system that can cater for both rockfall and rockburst incidents. The application has been successfully applied over many years. Operations have different geotechnical conditions and practical considerations, which has led to the development of various types of mesh and integrated mesh-based support systems (i.e. meshing and lacing versus welded or chain-link mesh sheets). Typically rolls or sheets of mesh is pinned with rockbolts to the surface of an exposed excavation. Applications vary from hangingwall coverage in a conventional stope gully to complete excavation coverage in footwall drives of conventional mines or on-reef drives in massive mechanised mines. It is however critical to understand the behaviour of the rockmass and apply suitable support systems.

Apr 26, 2022

By S. J. Schatzel, R. B. Krog, H. Dougherty

Longwall face ventilation is an important component of the overall coal mine ventilation system. Increased production rates due to higher-capacity mining equipment tend to also increase methane emission rates from the coal face, which must be diluted by the face ventilation. Increases in panel length, with some mines exceeding 6,100 m (20,000 ft), and panel width provide additional challenges to face ventilation designs. To assess the effectiveness of current face ventilation practices at a study site, a face monitoring study with continuous monitoring of methane concentrations and automated recording of longwall shearer activity was combined with a tracer gas test on a longwall face. The study was conducted at a U.S. longwall mine operating in a thick, bituminous coal seam and using a U-type, bleederless ventilation system. Multiple gob gas ventholes were located near the longwall face. These boreholes had some unusual design concepts, including a system of manifolds to modify borehole vacuum and flow and completion depths close to the horizon of the mined coalbed that enabled direct communication with the mine atmosphere. The mine operator also had the capacity to inject nitrogen into the longwall gob, which occurred during the monitoring study. The results show that emission rates on the longwall face showed a very limited increase in methane concentrations from headgate to tailgate despite the occurrence of methane delays during monitoring. Average face air velocities were 3.03 m/s (596 fpm) at shield 57 and 2.20 m/s (433 fpm) at shield 165. The time required for the sulfur hexafluoride (SF6 ) peak to occur at each monitoring location has been interpreted as being representative of the movement of the tracer slug. The rate of movement of the slug was much slower in reaching the first monitoring location at shield 57 compared with the other face locations. This lower rate of movement, compared with the main face ventilation, is thought to be the product of a flow path within and behind the shields that is moving in the general direction of the headgate to the tailgate. Barometric pressure variations were pronounced over the course of the study and varied on a diurnal basis.

Jan 1, 2018

By S. J. Schatzel, R. B. Krog, H. Dougherty

Longwall face ventilation is an important component of the overall coal mine ventilation system. Increased production rates due to higher-capacity mining equipment tend to also increase methane emission rates from the coal face, which must be diluted by the face ventilation. Increases in panel length, with some mines exceeding 6,100 m (20,000 ft), and panel width provide additional challenges to face ventilation designs. To assess the effectiveness of current face ventilation practices at a study site, a face monitoring study with continuous monitoring of methane concentrations and automated recording of longwall shearer activity was combined with a tracer gas test on a longwall face. The study was conducted at a U.S. longwall mine operating in a thick, bituminous coal seam and using a U-type, bleederless ventilation system. Multiple gob gas ventholes were located near the longwall face. These boreholes had some unusual design concepts, including a system of manifolds to modify borehole vacuum and flow and completion depths close to the horizon of the mined coalbed that enabled direct communication with the mine atmosphere. The mine operator also had the capacity to inject nitrogen into the longwall gob, which occurred during the monitoring study. The results show that emission rates on the longwall face showed a very limited increase in methane concentrations from headgate to tailgate despite the occurrence of methane delays during monitoring. Average face air velocities were 3.03 m/s (596 fpm) at shield 57 and 2.20 m/s (433 fpm) at shield 165. The time required for the sulfur hexafluoride (SF6 ) peak to occur at each monitoring location has been interpreted as being representative of the movement of the tracer slug. The rate of movement of the slug was much slower in reaching the first monitoring location at shield 57 compared with the other face locations. This lower rate of movement, compared with the main face ventilation, is thought to be the product of a flow path within and behind the shields that is moving in the general direction of the headgate to the tailgate. Barometric pressure variations were pronounced over the course of the study and varied on a diurnal basis.

Jan 1, 2017

By Robert G. Lundquist

REAM (for Rapid Excavation And Mining) is a method of rock fragmentation by high-velocity projectile impact developed by Physics International Company. This paper reports the results of field testing over the last two years. The success of the method is based on the fact that the amount of rock broken per shot scales nonlinearly with projectile impact energy. Thus, high energy impact yields spectacularly low specific energies for rock breakage. The field work reported used 90- and 105-mm military guns to accelerate 8-1/2 and 10-pound concrete and steel projectiles to velocities of 5000 to 5500 fps. All tests were performed in a competent 25,000 psi granodiorite at Hope Valley, California. During the first year of field testing 26 feet of 13-foot-diameter tunnel were produced with the 105-mm gun. The first 20 feet of this tunnel were line-drilled to aid in producing a stable portal. During the second year the tunnel was extended an additional 29 feet using the 90-mm gun. The 55-foot tunnel was produced by 590 shots. Between 1-1/4 and 1-1/2 tons of granite were broken by each shot. A silenced 90-mm gun was placed underground and the tunnel portal closed with a steel barrier. Overpressures of less than 1 psi were measured on the inside of the barrier, corresponding to an impulse noise of about 170 db. The muck produced was similar to drill and blast muck. Overbreak and ground support problems appeared to be less than with drill and blast. The contour of the tunnel was easily controlled using the 90-mm gun; the tests were also conducted using a 57-mm gun for trimming. Projections indicate that advance rates with REAM will be three to seven times faster than drill and blast, at less than two-thirds the cost. This is based on the development of a fully integrated continuous system and an inexpensive propellant giving a total expendables cost of less than $3 per shot. Other applications of the REAM technology are found in secondary breakage for open pit mining, in drilling large diameter holes, and in underground mining for longwall mining, overhand stoping, and raising.

Jan 1, 1974

By T. Emery, D. Sweet, J. Bourgeois, B. Seymour, D. Porter

Cemented rockfill (CRF) is being used to backfill primary and secondary stopes at the Eagle Mine, an underground nickel and copper mine operated by Lundin Mining. National Institute for Occupational Safety and Health (NIOSH) researchers from the Spokane Mining Research Division (SMRD) are conducting cooperative research with the mine staff to determine if the size of a CRF sample affects its measured strength properties. Based on previous research by NIOSH, cylindrical samples of CRF ranging in size from six to eighteen inches in diameter were cast at the mine and cured underground. The samples were later transported to the SMRD laboratory and the Michigan Technological University where tests were conducted to determine the strength and elastic properties of the CRF. To further analyze the relationship between backfill density and compressive strength, different ASTM International compaction techniques were used to cast the samples. For comparison, tests were also conducted on in-situ core samples that were drilled from a stope which had been backfilled with the same CRF mix. The data collected from this study not only improves our understanding of CRF in-situ properties but also helps optimize Quality Assurance/Quality Control (QA/QC) methods for backfill preparation and testing.

Feb 1, 2023

By Robert D. Thomson

The plastics industry runs into the billions, both in the dollar value of its finished, products and in the pounds of plastic raw material produced. It is, too, one of the fastest growing industries with a 300 percent increase in production in the past ten years. Informed estimates set 5.9 billions pounds as the plastic volume for 1959. Statistically, this is equivalent to a per capita consumption of 25 pounds in the United States. Plastics are man-made materials in contrast to natural materials like wood and are a family of materials -- not a single material - each member having special advantages. A generally accepted definition; for plastics is; a large and varied group of materials which consist, wholly or in part, of combinations of carbon with oxygen, hydrogen, nitrogen, and other organic and inorganic elements. This, while solid in the finished state, at some stage in its manufacture is soft enough to be formed into various shapes, most usually through the application either singly or together of heat and pressure. Many combinations and many different materials are thus possible. Therefore, for purposes of simplification, most plastics can be classified under one of 14 recognized basic family groups. These groups in turn generally can be further classified into one of two major subdivisions - thermosetting or thermoplastics. A few plastics are in between and they can be formulated to be either thermosetting or thermoplastic.

Jan 1, 1960

By B. G. White

Traditional interpretations of vein ore deposits in the Coeur d' Alene Mining District, such as the view that these deposits formed in a transcurrent tectonic regime during the Precambrian, are being supplanted by the view that the deposits (1) formed in low-grade metamorphic shear zones similar to those that host an important type of gold deposit, (2) display features, such as wall rock carbonate zoning and vein zoning, that are common to ore deposits elsewhere, and (3) are probably Mesozoic and possibly related to emplacement of the Idaho batholith. In recent years, new interpretations have led to major ore discoveries that are likely to extend the life of the district for decades.

Jan 1, 1998

By P. Guliov

In the first part of this paper the authors present an overview of industrial minerals produced in the Canadian provinces of British Columbia, Alberta and Saskatchewan, and supplied to the Pacific Rim countries. The second part outlines some of the unique opportunities for industrial minerals that exist in the three western Canadian provinces and those minerals we feel have development potential for overseas markets. Because of time constraints, it is not an exhaustive presentation on industrial minerals, but is focused on a few selected minerals that we believe have high potential.

Jan 1, 1990

By S. A. McGhee

ASARCO Incorporated embarked on a modernization and expansion program to improve overall operating efficiencies and to more effectively develop the large mineral reserve at the Ray Complex Open-Pit Mining operation located near Kearny, Arizona. Major elements of this Ray Modernization and Concentrator Expansion Project included engineering and construction of a 54,400 MTPD (60,000 STPD) In-Pit Crusher and Overland Conveying System. and a 24,200 MTPD (30,000 STPD) Copper SAG Concentrator and Tailings Disposal System. Detailed engineering, procurement, and construction management were initiated in November 1989 under contract with Bechtel Corporation. Field construction commenced in May 1990 leading to mechanical completion and start-up during February 1992.

Jan 1, 1993

By H. EI-shall

Bench top centrifuge is used to study the consolidation behavior of phosphatic clays. A mathematical model (based on first order kinetics) is developed to describe the relationship between the void ratio (at any time) and the effective stress. Permeability of the sediment as a function of the void ratio is also described. The obtained data are compared with that obtained by other consolidation testing methods. Centrifuge results indicate that consolidation data may be developed in a short period of time (hours) as compared to days or weeks when other techniques are used.

Jan 1, 1995

By W. H. Jang

Although surface chemistry fundamentals of semi-soluble minerals have been studied by many researchers, detailed understanding of these systems is still incomplete. In-situ FT-IR/IRS techniques have recently been used to successfully describe the adsorption of carboxylates at semi-soluble mineral surfaces. However, the wetting characteristics of these adsorbed films require further consideration. In this regard, the hydrophobicity and stability of transferred Langmuir-Blodgett (LB) monolayers of fatty acids at fluorite and calcite surfaces has been studied by contact angle measurements with polar and apolar liquids. Generally, it was found that the transferred LB monolayers of fatty acids at a calcite surface are unstable whereas such monolayers transferred at a fluorite surface are stable, as revealed from advancing and receding contact angle measurements. These results are believed to be due to the incomplete reaction of fatty acid monolayer at the calcite surface. In addition it was found that a closely packed well-ordered stearate monolayer with good hydrophobicity, equivalent to that of a transferred LB monolayer, can be formed at fluorite surfaces by spontaneous adsorption and self-assembly from aqueous solutions.

Jan 1, 1995