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By Dennis E. Peterson

Land subsidence had been observed in recent years throughout the Southwest. Particular examples of this phenomenon that have gained wide publicity axe in the Long Beach and Central Valley areas of California and, the Houston area of Texas. Less well known is the fact that the land surface Is subsiding in many parts of Arizona, including the Phoenix area. The causes of this problem vary from place to place, as do also the rates of subsidence. In Houston it has been related to pumping water from artesian aquifers; in Long Beach to the development of oil fields; and in the Central Valley to both the lowering of artesian pressures in deep aquifers and the wetting of poorly consolidated surficial deposits. The mechanism by which subsidence occurs in southern Arizona, even though it can be correlated with the continued lowering of ground water levels, is not as apparent as in these other cases. It is the purpose of this paper to examine both the causes and affects of land subsidence in southern and central Arizona.

Jan 1, 1965

By R. C. Gilmore

Computational fluid dynamics (CFD) has been used to model gas compositions in underground longwall coal mine gobs to study oxygen ingress and the development of potentially explosive methane-air mixtures that may form in the gob. The scenarios studied involve various headgate and tailgate ventilation and inertization schemes and controls. In a project sponsored by the National Institute for Occupational Safety and Health (NIOSH), researchers at Colorado School of Mines have used an innovative meshing approach, allowing easy adaptation of the CFD model to adjust to a variety of bleeder and bleederless mining geometries, with gob porosity and permeability scalable over a wide range. This paper presents the methodology of the meshing and scaling approach along with recommendations for using CFD modeling in longwall gob ventilation applications. The new meshing technique was utilized to evaluate the function of a back return in a progressively sealed gob. The back return was successful in maintaining sufficient oxygen concentrations in the tailgate corner of the longwall face.

Feb 23, 2014

By W. G. Pariseau

Recent advances in rock mass mechanics and computational technology now allow for stability analysis of excavations in "wet" mines where mining-induced changes in rock mass deformation and fluid flow are coupled and time-dependent. All the usual dry mine parameters including the premining stress state and rock mass properties are taken into account, in addition to water pressure and flow in jointed, possibly porous, rock masses. Finite element analyses of shafts and tunnels as circular, elliptical, rectangular and arched-rectangular hole shapes excavated in an initially stressed and pressurized rock mass indicate that the usual guidelines for optimum shape and orientation of single openings apply. Here, optimum means maximizing the minimum wall safety factor, or equivalently, minimizing the peak stress concentration. The results also show that failure originates in elements at the wall and that the minimum safety factor at the wall in the wet case is always less than the dry case regardless of drainage time allowed.

Jan 1, 1995

By R. J. Matetic

Mining operations have long been accused of causing a disruption to local, domestic and agricultural water supplies. More recently, concern for water supplies has increased with the advent of high-extraction mining techniques, namely longwall mining. Theoretically, any water bearing zone in the overburden above a high-extraction mining operation may be affected by mining. In some cases, a confining bed may be fractured causing a loss of water to a particular zone. In other cases, increased fracture permeability may enhance the ability of an aquifer to transmit and deliver water. Unfortunately, only a limited amount of studies have been conducted that characterize hydrologic changes and also quant1fythe magnitude of mining-induced subsidence. The U.S. Bureau of Mines conducted such a study at a mine site located in Greene County, PA. A total of 8 water wells were drilled and hydrologic parameters such as specific capacity, transmissivity and well yield were determined both before and after mining. Electronic water level recorders were installed on each water well to provide continuous observations of water level fluctuations.

Jan 1, 1990

By F. Heivilin

If the past is the key to the future, we will have ?tough? times maintaining Industrial Mineral reserves we have and proving new reserves around our plants and in new locations. The tough times will come from resources being more difficult to find, more hoops to go thru to make them Proven or Probable reserves. As always, Industrial Minerals require competitive quality, location, and costs. Since in most cases the market has suppliers, you will have to take away customers from their present supplier. This may take years or not happen even with lower cost higher quality raw materials. To determine the finished cost for a new deposit you need to design, determine capital costs, and operating costs for a new plant . Stripping, mining, hauling, processing, and transportation costs are part of the equation. After satisfying that your costs are in line you will need to do production tests to make sure the process works on the ore. You may want to complete permitting before purchasing the property. If you are new in the business you will have to prove you can deliver the right quality, the right quantity, on time consistently year after year at lower cost to take away a customer. Without being in the market this will be hard. The cut off grades to enter a market may be much lower than sale indicates because a competitor often lowers the price to keep you out of the market. We have many more items to check before the new deposits can be put on reserves. Our old reserves will require drilling to check for new products and prove that they do not contain items that would make them unusable for our product line or cause permitting problems. Archeological checks, wetlands, more water discharge testing, county zoning, and endangered species are among many items that have been added to mine permits. There will be more. A 4-6 page mining permit becomes 30-300 pages and consists of 5-15 permits, any of which might be a fatal stumbling block. It is not guaranteed that we can mine what we have on reserves. We may fight and lose. Oil-Dri?s loss in Reno and LaPort?s in England are examples where permitting failed. The NOx, sulfur, and carbon problems are just starting. Dioxin is in the background requiring monitoring on food products to Europe. What other anions, cations, endangered species, and land types are going to be problems in the future are guesses now. What new products are we going to have to test for and cause out of balance reserves? If there are none we probably won?t be here. We are competing for land use with ?Endangered Species?, wetlands, farming, forestry, cities, roads, and hunting. We?ve mined the best quality, low overburden, easiest to mine and process raw materials. The price of land and taxes are increasing. Old royalties are 2-3 times the present acre value instead of 8-10 times the property value when leased. Land taxes are up. It was and is best that we get the land in Fee Simple Title. This isn?t always possible. However, plants are closing and people have overlooked, made mistakes in drilling or interpretation of deposits. These may be opportunities. China is eating up high quality ?Industrial Minerals ?which have caused prices to rise. We may need to change our cutoffs? in terms of smaller pit sizes and higher overburden ratios. This is money in the bank. Overburden ratios and other items increasing cutoff costs need to be rethought. Suddenly doubling cutoff ratios for overburden and decreasing pit sizes are good alternatives to looking elsewhere where we might not be able to mine for a number of reasons. The higher prices make them competitive, especially when a competitor goes out of business. However, our low overburden ratios and short hauls around our plants are not safe from new roads, condemnation by county or city governments (N. J.), zoning changes (Reno, FL., CA, and environmental regulation changes (Buffers GA, MS). New roads ?Interstates? can take reserves, increase hauling distances and reduce tons per load. Let?s combine the Refractories, fullers earth, and bentonite industries and use the last 40 years as a guide to the future looking for problems and opportunities. Some or most of the following will apply to other minerals. WHERE DO WE LOOK? First, on our own properties, those next to our properties and on properties near our competitor?s plants. Where the profit margin has increased, the distance from the plant and thickness of overburden we can use is increased. The thickness of clay is decreased. For new locations we pick the ideal location and look at deposits and closed or open operations in ever increasing distances away from that location. We need to be aware of: 1. Increased transportation costs a. Access to Roads -Backhauls b. Haul with doubles and triples c. Railroads - Loading on sidings - Ability to get switches - Cars/backhauls versus rates 2. Cost of building a new plant 3. Cost of infrastructure 4. Cost of repair or new equipment when purchasing an operating or shutdown plant. 5. Local, state, and federal mine and environmental permitting. When exploring around an established operation expect that property acquisition, drilling, mining, stripping, and hauling costs will be greater due to them having second, third, or even fourth the pick of the deposits. I found this in New Jersey looking for refractories and around Quincy, Florida looking for attapulgite. You may be able to get some better properties because the operating company has angered some land owners, their drillers missed the clay, or the property wasn?t available when they were actively exploring for reserves. You may have some product lines your

Jan 1, 2009

By Bruce D. Hanson

A computer model capable of simulating the basic production system in a variety of underground mining methods has been developed at the Twin Cities Mining Research Center. This Bureau of Mines paper describes the simulation of the basic production system at the working face, which includes drilling, blasting, mucking, and roof bolting. The model is event-oriented; that is, the status of the system is updated at the occurrence of an event. All event or activity times, including failure and repair of equipment, are treated as stochastic variables. A location dimension, in addition to the time dimension, is used, allowing the simulation of multiple location systems. To aid the user in determining the efficiency of his system, the model provides several reports. An event or activity report gives the frequency of occurrence total active time, and cumulative delay statistics for each event. An equipment report delineates the availability and utilization of all equipment. A production report provides information on various performance measures such as tons produced and holes drilled. The cost report gives the cost of various elements in the system. Operating data from an actual mining situation were used in validating the model. In addition to the description of the model, examples of simulation experiments which were performed on a room-and-pillar mine system are given. Use of the model to determine methods for improving the efficiency of the system is discussed.

Jan 1, 1974

By W. W. Hartley

Following a Major underground coal mine incident there followed a review of the role of mines rescue ? the Queensland Mines Rescue Brigade. It wasn?t until 2002 that the real change started to happen. The issue of geographical distance was addressed by mines rescue sub stations being located on the mines sites with parent rescue stations in a central location. The funding was by means of a levy on the mining industry with legislative standards and performance included. The previous Rescue Brigades were not well organised (central districts) and the application of recognised quality management practices within local management was lacking. The structure was based on other nations models and miners managing miners was an issue for the organisation. The reform was some what painful and the QMRS organisation will still evolve with continuous improvement. Queensland has the National Champion mines rescue team for the eighth year. QMRS is participating at the level in the industry of influencing emergency systems and training senior mine management in ?Emergency Mine Management? coaching the industry in emergency response systems. We have come a long way. We have had some success and there is always the challenge of setting the standards, those we should aspire to and the courage to influence the industry to higher goals of a safer future.

Jan 1, 2010

By B. J. Vorster

Introduction The South African Iron and Steel Co. Ltd., in Sishen, operates a large iron ore mine in the Cape Province of the Republic of South Africa. The mine is about 600 km (370 miles) west of Johannesburg. Its annual capacity is 100 Mt (110 million st) of ore and waste. Present production is 60 Mt/a (66 million stpy). The mine operates continuously six days a week. Primary equipment includes 55 154 t (170 st) Wabco and Unit Rig trucks and 14 P&H shovels. During 1979, a feasibility study into the application of a trolley assist system was launched. This was due to the escalation in diesel fuel costs and the appeal by the South African government to reduce the use of fossil fuels. Tests and economic evaluations proved the system technically feasible. The estimated discounted cash flow return exceeded 50%. Diesel fuel consumption would be reduced by 120 ML (31.7 million gal) in the next 10 years. The construction of 7.7 km (4.8 miles) of line and the conversion of 66 154 t (170 st) trucks were completed in March 1982. System description The conventional 154 t (170 st) diesel electric rear-dump haul-truck is equipped with two direct current wheelmotors in the rear axle. They drive the rear wheels through planetary gearboxes. A 1.2-MV (1600-hp) diesel engine and an alternator is used to power the wheelmotors. The trolley assist system consists of an overhead power line, a current collector mounted on the truck, and add-on control equipment where external electric power is routed by way of the current collector to the motorized wheels. The diesel engine is used to propel the truck on level sections. On inclines, the wheel-motors of the truck are coupled by way of a current collector to the externally generated electrical power supply for propulsion. The diesel engine, having lower output than the wheelmotors, limits the truck performance. Previously, maximum output was required from an engine on inclines. By supplying the wheelmotors from a virtually unlimited outside electric energy source, the truck performance is enhanced to the extent that speed is increased by 46% and fuel consumption reduced by 75%. System design The unique operational requirements of this mine rendered the already proven trolley pole system useless. Minimum loss in truck mobility and flexibility was required. Overhead lines and substations were required to be relatively light and portable. This enables fast repositioning of a line with no loss in material. These unique specifications set the base for the design of the Sishen system. Steel I-beams, 203 x 203 mm x 52 kg/m (8 x 8 in. x 35 lb per ft) with lengths varying from 8.3 to 11.3 m (27 to 37 ft), mounted on base plates about 4 x 2.6 m (13 x 8.6 ft) were used as masts. The masts were erected at about 50 m (165 ft) and the base plates covered with about 12 t (13 st) of iron ore to keep them absolutely stable. Results from the pilot installations indicated that using single cantilever cross arms for insulator and overhead conductor suspension was not practical. The tension in the overhead varied too much with temperature changes, causing too much sag in the lines. There had to be a positive and negative conductor. It was decided to suspend each polarity on an independent cantilever and keep the conductors under constant tension by weights acting through a two-to-one pulley tensioning arrangement. For each overhead conductor, a standard 160-mm (6.5-sq in.) grooved copper railway conductor was used. To obtain the necessary current carrying capacity, two of these conductors are used in parallel per pole. Insulators are rated at 4 kV and are of the composite type. An 11-kV three-phase line, supported by the pantograph line masts on the opposite side of the dc line, feeds the rectifier stations. The rectifier stations consist of an 11-kV to 860-V, three-phase 1.46 MVA transformer and a three-phase diode bridge rectifier. The output voltage is 1200 V do earthed through a current limiting resistance network so that the line po-

Jan 4, 1986

By DING TANG, JINGHE CHEN, Shuiping Zhong, CHEN KUANG

The Zijinshan gold-copper mine, in spite of the low-grade nature of the ore, has become one of the largest production-scale and most profitable non-ferrous metal mines in China. The successful application of hydrometallurgy as well as proper engineering design are the key factors for large-scale development of the Zijinshan gold-copper mine. In this contribution, the practical experience acquired in the development of the Zijinshan gold and copper mines is summarized. This covers most aspects of the production process including mining, beneficiation, ore stacking, heap (bio)leaching, carbon-in-leach, solvent extraction, electrowinning, wastewater and tailing treatments. The authors believe that this practical experience will not only help to promote the development of hydrometallurgy, but can also serve as a model for other gold and/or copper plants around the world.

Jun 3, 2020

By J. M. Keating, R. L. Wiegel

Those processing plants which depend on flotation for their mineral separations are always looking for reagents which are cheaper, more selective or in some other way may provide improved economic performance. This paper describes the rationale for and some results from applying a statistically based approach to reagent testing in those flotation plants which still rely on experienced operators for manual flotation control.

Jan 1, 1986

By SANDEEP KUMAR JENA

This review work reports the recovery of potassiumfromdifferent rocks and mineral sources. The global demand for potassiumis rising consistently due to the growth of agricultural production. A major portion of the world potassium production is consumed in making of fertiliser; however, other uses include those in pharmaceutical, glass, ceramic, food and detergent industries. The availability of soluble potash minerals (sylvite, kainite and carnallite) in different countries like Canada, USA, Israel and Russia makes them as major potash producers, whereas agricultural-based countries like Liberia, Somalia, Central African Republic, Thailand, Indonesia and Malaysia including India meet their potassium requirement through import only. On the contrary, the availability of huge potassium-bearing rocks/minerals (like nepheline syenite, feldspar, mica, glauconitic sandstone) in these countries containing around 4–17% K2O would be a prospective for commercial production of potassium. The potassium recovery from minerals/rocks is very complicated due to the uniform distribution of potassium throughout the crystal structure. Different physico-chemical separation methods like bioleaching, chemical leaching, flotation and roast leaching have been discussed for the successful recovery of potash values from these rocks/minerals. However, the recovery of potassium from hugely available seawater using the chemical precipitation, solvent extraction,membrane separation and ionic exchangemethods is not cost-effective due to the low concentration of potassium.

Aug 31, 2020

By Cory Bolen, Nadav Bar-Yaakov, Eric Zimmerman, Gregory Raines

The Chimney Hollow Reservoir Project broke ground in August 2021, constructing the tallest Asphalt Core Dam in North America, intending to improve reliability of drinking water supply to Northern Colorado communities. Aiming to expedite and streamline the geological mapping process in the tunnel, Stantec’s teams have developed a mobile and web-based GIS application for digital mapping input and rock mass evaluation, allowing real time decision making for assigning tunnel support class and resulting in a faster more efficient process. The following article presents and demonstrates the GIS mobile and web application-based process, the mapping results and review additional uses of the database created.

Jun 13, 2023

By R. Perlo

"INTRODUCTION Peoples’ and operators’ safety in construction are tightly linked to the engineering choices, as much as the necessity of reducing time and costs of realization. Therefore, it is of paramount importance to address them properly from the earliest stage of the design, identifying the risks connected to the work and the variability of such during the different phases of the project. Risk is often measured as the expected value of an undesirable outcome. Regarding to occupational safety and health, the risk is the likelihood that a person may be harmed of suffers adverse health effects if exposed to a hazard. This combines the probabilities of various possible events and the assessment of the corresponding harm into a single value. However, the actual occurrences are often more complex than a single binary possibility case. In a real case scenario, with several possible accidents, the total risk is the sum of the risks for each different accident, provided that the outcomes are comparable. The semi-automatic tunnel support system along with its erector machine proved to be a solution with improved structural performance, able to reduce the time and yet to deliver an enhanced, quality-aware and safer working environment for the operators. The implementation of the system provides the engineers, the contractors and the owners with an effective alternative option shortlisted in 2015 for the ITA Award for the Safety Innovation of the Year. In a market industry driven by safety and time constrains the efficiency shall be the ultimate goal, in order to provide solutions able to negotiate with the most challenging ground conditions. In this paper, the authors describe the recent developments on regard of this whole new tunnel support system, including design approach and presenting related case histories OFFSETTING THE RISKS Considering the above factors, from the manufacturers’ point of view, an effective way to limit the construction risks is to focus on the material and technological characteristics, their application and the risks related to them including any residual risks. Finally addressing the construction needs also involves time and cost-effective solutions. The path to follow is an integrated approach where the efficient management of the risk is supported by a flexible, user-friendly, and time effective product that is able to provide a safe, reliable and viable solution to address the construction requirements. Therefore, in a market sector driven by safety and time constraints, the efficiency is a key goal, in order to avoid redundancy and yet to deliver a safe working environment able to meet the construction schedule. The safety of all the parties involved is given by stable working conditions, either for the workers, or the operators and eventually the public. Therefore, the solutions provided should ‘strengthen’ the overall condition and such “to limit or to reduce the deformations within acceptable designed limits and to prevent [the tunnel] to collapse” [1: Clause 207.1.4]."

Jan 1, 2018

By P. C. Thakur

The productivity in coal mines, measured in terns of the output per manshift depends largely on the efficiency and speed of men and materials transport between working faces and the surface. The mechanization of coal winning and material handling processes has led to a great rise in the mine productivity (1). Early applications of power in U. S. coal mines were mainly electrical. The excellent traction available with the DC motor and the ease of the distribution of the DC power have made trolley wire installations for haulage very popular. In shallow mines with very limited emissions of methane it did not constitute a major hazard but as mine depths increased and corresponding emissions of methane also increased fire and methane ignition hazards have become very serious. Conveyors have proved economic where intense mechanization of coal faces generates a large output of coal from a single face, but the fire and respirable dust hazard associated with them are no less serious. Recognizing these shortcomings, the Federal Coal Mine Health and Safety Act of 1969 laid down numerous provisions for the safe use of trolley-wire haulage and conveyors (2) which generally improve safety but in some cases complicate mining operations and have decreased productivity significantly since 1969. In course of time as coal mines become deeper and hence gassier and as the emphasis on safety increases it would be inconceivable to use trolley-wire haulage under ground as already witnessed in several other countries with deep coal mines. With rising capital investments and cost of the protection against fire and respirable dust, the use of conveyors may also have to be limited to special areas, e.g. main entries. Indeed, there are only two alternatives available, namely; (1) Degasify the coal seams prior to mining and use conventional electrical power, or (2) Develop alternate sources of power which would be safer and yet efficient and cheap.

Jan 1, 1975

By J. Morris, R. Sellaro

Petro-diesel is a common collector for coal flotation, but the partitioning of diesel range organics (DROs) in process streams has not been widely studied. Preliminary research suggested that under normal dosing schemes total residual DRO contents in process waters should be limited to the sub-ppm water-soluble fraction (WSF). Further, polycyclic aromatic hydrocarbons (PAHs) should partition proportionately with DROs. The purpose of this study was to confirm these findings in laboratory flotation tests. Total DRO and specific PAH contents were measured in the waters associated with the concentrate and tailings streams. The results show that concentrate waters consistently had higher amounts of DROs than tailing waters. Moreover, the DRO contents in both streams generally increased with increasing diesel dosage. In line with preliminary research, DROs appeared to be limited to the WSF, and PAHs tended to partition proportionately with DROs. Under typical operating conditions, it appears that residual DROs should not present an environmental concern, but conditions should be avoided that allow significant overdosing of diesel.

Jan 1, 2014

By R. L. Garrett

The quality of mineral additives used 1n a drilling fluid (mud) can dramatically affect the fluid's properties and the overall cost of drilling an oil or gas well. The principally used minerals are bentonite, barite, barite/hematite blends and hematite alone. The high specific gravity minerals, barite and hematite, are used to increase drilling fluid density. Bentonite clay is used to increase drilling fluid viscosity, gel strength and to provide a low permeability filter cake. A multi-million dollar investment in a well and the safety of the personnel on the drilling rig can depend on how effectively these mud additives perform with other constituents in the mud. This paper points out effects caused by small amounts of certain carbonate and sulfide mineral impurities in barite or hematite and how polymeric extender additives in bentonites contribute to unpredictable behavior of a mud. Effects like these are the reason why oil companies who use these materials sometimes set their own quality standards beyond those already specified in API Spec. 13A. Also discussed in this paper are the current standardization activities in API Committee 13 on these minerals.

Jan 1, 1986

By Francis F. Pitard

The presence of elements, minerals, or chemical compounds in materials at very low concentrations is becoming a constantly increasing concern for several segments of the Industry. Some trace elements or chemical compounds may be considered as hazardous, some are simply considered as undesirable In complex processes where they could be constantly recycled and end up as the major factor of decreasing quality for some valuable products. In some other cases, the presence of a trace element or mineral may be highly desirable because of its economical value: precious metals are falling into this category, they probably were the first trace elements to draw our attention. Tremendous quantity of money is spent for analysis at the trace level, also the analytical "tool" has been considerably improved during recent years, but still the sampling aspect of the problem remains obscur for many, and because of it, large quantity of analytical efforts become meaningless. Not only the absence of sampling strategies is badly affecting the representativeness of a large majority of samples, but furthermore for the same reasons, many laboratories are failing In their endeavor to prepare reliable standard reference materials. The reason of this failure has its roots in the unability to estimate effectively the sampling characteristics of the element, mineral, or compound of interest, not to mention the unability to perform precise and accurate complete analysis, so essential for the instrumental analyst (1). In this paper a strategy to perform a better sampling operation is recommended. SELECTION OF A PROBABILISTIC APPROACH AS SOON AS PRACTICALLY POSSIBLE It Is essential to differentiate probabilistic sampling from non-probabilistic sampling. As Illustrated in Figure 1, the sampling operation Is a selection process which could be performed In two different ways: I. A probabilistic selection process according to which all elements of a lot of material to be sampled are submitted to the selection with a same probability of being selected. 2. A non-probabilistic selection process according to which all elements of a lot of material to be sampled are submitted to the selection with different probabilities of being selected.

Jan 1, 1986

By Viggo C. Bertelsen, David G. Hammond

LOCATION AND EXTENT OF BART TUNNELS The San Francisco Bay Area Rapid Transit District (BART) during the past six years has become the Owner of 23.5 miles of single-bore tunnels. The tunneling experience gained while working closely with our Engineer and Contractors in the design and construction of these major transit facilities provides a basis for our "Owners" viewpoint. The 23.5 miles of tunnels are divided into two categories. Fifteen and one-half (15-1/2) miles of tunnels were constructed in soft ground underlaying the downtown areas of San Francisco, Oakland and Berkeley. Eight (8) miles of tunnels were built in "hard ground" in the hills separating Oakland and Berkeley from Contra Costa County and in the San Francisco hills on the Mission Line. Location of tunnels within the BART system are shown on Figure 1. The tunnels comprise 15.7% of BART's 75-mile dual track system. Their 176 million dollar costs (excluding rail, electrification or ventilation features) are 12.4% of the system's total estimated cost of $1.4 billion. The tunnels constructed in soft ground were shield and boring machine driven with ground support provided by steel liner rings. The exterior diameter is 17 foot, 6 inches in the majority of tunnels; however, on two tunnels with a 500 foot radius of curvature, the diameter was 18 feet. BART awarded 14 contracts for soft ground tunneling. The work was accomplished under free air or compressed air depending upon the ground water and soil conditions, safety requirements, and considerations for protecting adjoining property from damage either from the de-watering operations or settlements due to excavation. The tunnel bores, except on curves, were normally parallel being spaced at 32 foot centers on the Mission

Jan 1, 1997

By E. A. Wieselmann

In 1970 Texasgulf (Australia) introduced natural gamma radiation logging of drill holes for exploration in the Hamersley Iron Province of Western Australia. Drill hole logs have allowed positive stratigraphic and structural correlations within complexly folded secondary hematite ore deposits and between individual iron ore deposits separated by distances in excess of seventy-five miles. A Neltronics model KPD logging system and gamma-ray sonde are being used to measure the natural gamma radiation of the enriched Brockman and Marra Mamba banded iron formations. The parent banded iron formations are composed of thick, chemically precipitated iron oxide, chert, iron silicate, and carbonate with thin intro-formational clastic horizons. These clastic horizons give a greater natural gamma radiation than the banded iron horizon, and each clastic horizon has a characteristic radiation profile related to its composition and thickness. Because the natural gamma-radiation profile is unchanged during secondary enrichment of the iron formation, the present stratigraphic position of each drill hole can be established and complex folding can be accurately traced in the sub-surface. Gamma ray logging of percussion drill holes has made feasible a significant reduction in diamond core drilling without loss of accuracy. At the same time, it has provided a means of rapid evaluation of complexly folded iron ore deposits.

Jan 1, 1975

By Naeimeh Shabani, Hamid Mirzaie, Javid Sadeghi, Hoda Jafarizadeh-Malmiri, Afshin Javadi

Iron oxide nanoparticles (Fe3O4 NPs), despite their small size, are stable and have a large surface area that allows for absorption and removal of ions as well as turbidity in a short period of time. Thus, the present study addressed the synthesis and characterization of Fe3O4 NPs synthesized using the co-precipitation method and evaluated their effect on the coagulation process in water treatment. The Fe3O4 NPs characteristics were evaluated as follows: magnetic properties were measured using a vibrating sample magnetometer (VSM), surface area using Brunauer–Emmett–Teller (BET), crystal phase using X-ray diffraction (XRD), and morphology using field emission scanning electron microscopy (FESEM). In addition, the effects of the synthetic Fe3O4 NPs on the turbidity reduction of water in various pH levels were evaluated. The synthesized Fe3O4 NPs were without any impurity in the sizes of 22–32 nm, surface area of 99.6 m2/g, pores’ mean diameter size of approximately 10.6 nm, and maximum magnetic saturation of 66.21 emu/gram (emu/g). Using 0.2 g of synthetic Fe3O4 NPs with an initial turbidity of 17 NTU and pH of 6 could reduce all water turbidity (100%). Considering the cheap and facile production and separation, as well as the possibility to reuse them and reduce the sludge water content, iron oxide Fe3O4 NPs can be effectively used for turbidity reduction in the water treatment process.

Oct 26, 2020