Search Documents

By E. McCullough, S. Gaillard

"Diesel particulate matter (DPM) remains a health concern in many underground metal/nonmetal mines, and has been regulated by the Mine Safety and Health Administration since 2002. While the NIOSH 5040 standard method for DPM monitoring is required to demonstrate regulatory compliance, the FLIR Airtec DPM Monitor can serve as complementary engineering tool. It is a handheld instrument that offers near real-time measurements. As part of an ongoing field study, the Airtec has been used to survey elemental carbon concentrations (a proxy for DPM) in an underground stone mine. Via “spot-checking” and more prolonged area monitoring, this effort was aimed at determining spatial and temporal DPM variation in several key locations. INTRODUCTION Diesel particulate matter (DPM) is the solid fraction of the exhaust emissions from a diesel engine. It is largely made up of elemental and organic carbon (EC and OC, respectively), which can be measured as proxies for estimating mass concentrations of DPM. The National Institute for Occupational Safety and Health (NIOSH) considers DPM to be a health hazard and potential carcinogen [1]. It is believed to cause and/or exacerbate respiratory illness upon inhalation, deposition, and retention in lung tissue [2]. Since DPM exists in both the micro- and nano-particulate ranges, it can surpass typical auto-immuno defense mechanisms that keep larger particles out of the respiratory system [2]. Relative to other occupations, the DPM exposure potential for underground miners is high because these individuals work in enclosed environments where diesel powered equipment is frequently used [3,4]. A variety of engineering and administrative controls have been devised to reduce DPM exposures in underground mines, and increased airflow is often a key component of control strategies. In large-opening mines, which are most common in the metal/nonmetal sector, DPM abatement via increased ventilation can be especially complex due to moving and controlling the large air quantities [5]. The Mine Safety and Health Administration (MSHA) has regulated DPM exposure in metal/nonmetal mines since 2002. The final rule limits personal exposure to total carbon (TC, which is the sum of EC and OC) to an eight-hour time weighted average (TWA) of 160 µg/m3. To demonstrate compliance, operators must use the NIOSH 5040 Method [6]. However, the Airtec DPM Monitor (FLIR Systems, Inc., Nashua, NH) was developed as an engineering tool to provide near real-time measurements of both EC and TC for tracking personal exposures [7]. The portable Airtec works by capturing DPM on a filter and successively measuring laser extinction on the filter as DPM accumulates; the EC fraction of the DPM is dark, and so as it accumulates the filter becomes darker and absorbs more laser light [8]. The laser extinction value is directly correlated to EC, but since EC and TC are generally observed in consistent proportions (i.e., TC = EC*1.3), the Airtec is also programmed to display TC as a TWA [9]. There have been multiple studies conducted to validate the Airtec and the instrument has been adopted by some mine operators as a tool for their health and safety programs [3,8]."

Jan 1, 2016

By J. W. Marx, R. H. Langenheim

The authors are to he complimented for a timely presentation of useful information concerning application of heat to oil reservoirs to increase the rate and ultimate recovery of oil. The solution for heated area resulting from constant rate injection of a hot fluid, presented by the authors, and the fluid-flow analogy, solved by Carter,' are particularly interesting in that 110 restriction is placed on the direction of development of the heated area. It is not necessary that the heated area grow radially. Thus the solution could provide useful information for heat injection in any type of well pattern with any specified swept area data. However, it was assumed in the development that the heated region would remain at a constant clevatcd temperature. Vertical heat losses were computed on this basis. Physically. the assumption that the heated region will remain at a constant temperature (independent of distance from the injection point) appears to require that the heat injection medium be stcam, or other condensible gases near the boding point at injection pressure. If a hot liquid below the boiling point or a hot gas considerably above saturation temperature were used, the temperature of the heated region would decrease with distance from the injection well. Lauwerier2 has discussed this problem for a linear system. (See also Jenkins and Aronolsky; and McNiel and Nelson.') Thus, the authors' solution applies more nearly to steam injection than to hot water injection or hot, non-condensable gas injection. Assuming steam as the injection medium, it appears that steam would pass through the constant-temperature heated region and condense upon contact with the unheated sand. The tempcrature in the condensing region would probably be governed by the release of heat of vaporization required for phase equilibrium at the existing pressure distribution. Temperatures in the region would also be influenced by vaporization of hydrocarbon. Thus, it is doubtful that an expression for radial temperature distribution based on heat conduction only (such as the authors' Eq. 9) would have practical significance. As pointed out by Marx and Langenheim, the growth of the heated area under constant rate steam drive will eventually be limited economically by vertical heat loss. The possibility of continuing to move heat economically by cold water injection or by increasing the steam injection rate appears to be a very important consideration. (Movement of liquids away from the injection well should increase injectivity.) Fortunately, the solution presented by the authors may be generalized to thc case of a variable heat injection rate. The general solution is:

By Webster S. Anderson

The design, development, and testing of hydraulic props to provide a lightweight, high strength, recoverable unit is described. Modifications in design incorporating threaded components resulted in the development of a lightweight hydraulic prop fabricated from aluminum alloy tubing. This new design facilitates interchange and replacement of component parts, and the physical properties of the material are not changed as they are when welding is required. The new prop is 65,000 pounds and has a maximum load capacity of a lower weight-to-load capacity ratio than the hydraulic props now available.

Jan 1, 1967

By Oliver Bowles

"Asbestos" is not the name of a distinct mineral species but is rather a commercial term applied to fibrous varieties of several minerals. The origin and significance of names applied to asbestos by early writers are discussed in the section devoted to sources of supply and terms employed in ancient times. VARIETIES The most useful variety of asbestos is chrysotile, a fibrous serpentine the composition of which is expressed by the formula H4Mg3Si209. Chrysotile is characterized by a strength and flexibility that permit the use of the longer fibers for spinning. The bulk of the world production of both long and short fibers, is of this variety.

Jan 1, 1935

By Walter Kawa

Bureau of Mines research on the hydrogenation of coal has been concerned with developing processes that could be used to supplement the Nation's petroleum and natural gas resources. Motor fuel was produced in a subsidized coal hydrogenation industry in Europe prior to 1945, but the process used is still not economical and other methods of producing liquid and gaseous fuels from coal are being investigated. As an aid to the planning of coal hydrogenation research, a literature survey was made of processes or methods of hydrogenating coal that differ from the subsidized or conventional process. This report contains a bibliography of unconventional methods of hydrogenating coal and a brief discussion of the economics of the conventional method. A general discussion of unconventional methods is included, and the advantages and disadvantages are pointed out where possible. The survey supplements a previous Bureau of Mines survey3 and a comprehensive review published in 1930.4

Jan 1, 1964

By Donald Leroux, Simon Gariépy, Luc Lachance

"Quantitative information about the quality of metal balance results is often overlooked when making important plant production planning decisions. Not only is this common omission made in a context where many measurements taken in and around mineral processing plants carry significant errors, but it also conflicts with the AMIRA P754 Code of Practice for Metal Accounting. The fact that metal balances are typically published without any indication of data quality may give the wrong impression that the measurements are unquestionably accurate. While it is true that statistical data reconciliation can improve the confidence intervals of redundant variables, there is no data processing technique that brings them down to zero at a finite cost. In this paper, we review the entire data flow, starting from field instruments to metal accounting-based decision-making to show how measurement errors are transmuted into business risks associated with production planning. Necessary conditions for first exposing then quantifying such business risks are stated. Pitfalls to be avoided are also discussed. Finally, a simplified risk assessment and management procedure which considers the quality of metal balance results are applied to a polymetallic mineral processing plant. INTRODUCTION Each and every mineral processing plant has production reporting obligations. In this paper, we are concerned with metal accounting reports (Morrison, 2008) where saleable metal flows and inventories are estimated and published. These metal accounting reports are delivered to a variety of stakeholders who use them for internal management purposes (day-to-day plant production planning, plant operation optimisation, capital spending, etc.) as well as for external management (royalty settlements, tolling agreements, etc.). Hence, there should be no doubt that spotless metal accounting is instrumental to high-quality corporate governance (Gaylard et al., 2014) of mining and metallurgical companies. To this extent, one would have expected industry-endorsed standards to have emerged a long time ago. However, the lack of an accepted set of standard procedures for metallurgical accounting was explicitly recognized as an industry-wide problem only in August 2001 during an SAIMM workshop held in Cape Town, South Africa. Discussions that followed this workshop led to the initiation of the AMIRA Project P754, “Metal Accounting and Reconciliation”, in 2003."

Jan 1, 2015

By Tracy Brettmann, Melis Sutman, C. Guney Olgen

"The use of energy piles for geothermal heat exchange has been steadily increasing during the last decade, yet there are still pending questions on their behavior during temperature changes. This paper focuses on the thermo-mechanical response of three full-scale energy piles installed in Richmond, TX. The behavior of test piles subjected to thermo-mechanical loadings was studied in situ with the aim of quantifying the thermal influence on the performance and capacity of energy piles. An extensive field test program, including conventional pile loading tests and application of heating-cooling cycles was conducted on the test piles during a period of six weeks. For thermal load applications, the heat exchanger fluid with maximum temperature of 113°F (45°C) and minimum of 47°F (8°C) was circulated in the geothermal loops placed at the center of the test piles. Optical fiber sensors, vibrating wire strain gages, thermistors and thermal integrity profile wires were installed to monitor the strain and temperature variations along the energy piles throughout the field tests. The strain and temperature profiles during heating-cooling cycles on the test piles under static loads and without a maintained load were monitored to investigate the effect of thermo-mechanical and pure thermal loads on the energy piles, respectively. Conventional pile load tests were applied before and after the application of thermal cycles. The results of the pile load tests are compared to evaluate the effect of temperature cycles on pile capacity.IntroductionEnergy piles are deep foundation elements designed to access and exploit the relatively constant temperature of the ground and its heat storage capacity for efficient heating and cooling of buildings. The deep foundation elements that are already in place for structural support are integrated with adsorber pipes to perform as heat exchangers connected to ground source heat pump (GSHP) systems. With the use of energy piles, the heat energy is fed into and withdrawn from the ground for cooling in the summer and heating in the winter, respectively.Energy piles present an innovative way to harvest near-surface geothermal energy and to provide lower carbon emissions, however, there are still pending question on their performance. During heating-cooling cycles, energy piles experience temperature changes, which result in expansion or contraction of the piles."

Jan 1, 2017

By R Ayothiraman

Tunnel excavation may induce adverse effects on nearby existing structures/foundations in urban areas. Accurate prediction of tunnelling effects on pile foundations of nearby structures in the urban environment poses a major challenge during design. Several studies have been undertaken to understand the mechanisms of the soil-tunnel-pile interaction, which focused only on influence of tunnelling on nearby existing building and foundations. However, effect of pile loading on existing tunnels did not receive enough research attention so far. So it is essential to measure the response of existing tunnel-lining due to loading on newly constructed pile to assess to the safety against the additional forces/moment caused by pile loading and to evaluate the critical distance for the proposed construction of any structures from the tunnel location. This paper presents result of three-dimensional (3D) finite element analysis carried out in ABAQUS to investigate the effects of pile loading on existing tunnels embedded in cohesive soil. It is found that the effects on tunnel lining depend on horizontal separation distance between pile and tunnel as well as location/elevation of pile tip with respect to tunnel location.

Mar 8, 2011

By Christian Leble, Dr. -Ing. Jakob Vogelsang, Dr. -Ing. Oksana Solt, Dipl. -Ing. Joachim Meier, Dr. -Ing. Wolfgang Orth

In the course of closing the gap between the Brandenburg Gate and Alexanderplatz, the Museum Island station was built by Implenia Construction GmbH. The tunneling for the platform hall took place on a length of about 106 m (347 ft) under the protection of a major ground freezing measure and crossed the Spree canal as well as the listed castle bridge. The approximately 20,000 m³ (4.54 E+06 US gal dry) frozen mass lay mainly in the Berlin sands. In order to ensure safe tunnelling and to protect the adjacent buildings, the planners had defined requirements for the mean freezing temperature and thickness of the frozen mass. For a reliable conclusion on the dimensions of the frozen mass, we used innovative temperature sensors as well as the new, web-based 3D measurement visualization and the associated site-specific evaluation software. The largely automated evaluation enabled a quick and reproducible determination of the temperature distribution in the frozen soil and its thickness in the relevant cross-sectional areas. The measurements were validated by thermal calculations using the Finite-Element-Method. Thus, an objective and clear assessment basis was available to ensure rapid coordination between stakeholders. The evaluations provide new insights into the temperature influences from tunneling, the application of shotcrete and the concreting of the inner shell. The newly implemented active thawing system is also an interesting innovation.

May 1, 2022

By China University of Mining & Technology, Yuemin Zhao, Bo Zhang, Liang Dong, Zhenfu Luo, Chenlong Duan

"In China, approximately 65% of coal reserves are in the west region, where water shortage is a serious problem: high-efficiency dry coal beneficiation technology is desired. Using magnetic powder and fine coal as heavy medium, and using air as the fluidizing agent, a novel air dense medium fluidized bed separator is proposed for coal preparation. Coal can be efficiently separated according to density in the fluidized bed, where bed density is steady. The separator is highly reliable, the circulation quantity of heavy medium is low, and the gas distributor cannot be easily easily. The world’s first industrial modularized dry coal preparation plant was built by China University of Mining and Technology. Dry coal beneficiation technology was first used to produce low-ash coal. Results of industrial production show that the ash content of clean coal is 3.46%, the probable error E value is 0.055 g/cm3, and the organic efficiency is over 90%. The advantages of the modularized dry coal beneficiation system are the high separation accuracy, the simple process flow, the low operation cost, low energy consumption, and so on. This technology provides a new effective method for coal separation in acid region and coal tending to sliming.INTRODUCTIONCoal is the most important primary energy source in China, where coal output reached 3.68 billion tons in 2013 and represents approximately 68% of the primary energy consumption. Coal has made a great contribution to the development of the Chinese national economy, but it also brings serious environmental pollution. However, approximately 65% of coal reserves are in the arid west region in China where water shortages present a challenge for wet coal preparation technology. In addition, the abundant lignite resource, because it is easy to mud in the water, should not be treated with the wet separation method. Therefore, it is critical to develop highly efficient dry coal preparation technology to meet the demand in arid areas. Further, water resource shortages are a global problem, thus the development of efficient dry coal preparation technology in has potential application in other water-short countries like South Africa, Brazil, India and Turkey."

Jan 1, 2016

By M P. Sandy, R M. Stephenson

Portals to access underground mines are important infrastructure and their design requires careful consideration. Portals are generally expected to last for the life of the mine. Typically, the exposure of personnel and equipment is high, with many hundreds of movements through the portal per day. Consequently, the risk associated with geotechnical instability must be extremely low. Portals are often established from a boxcut. In areas where the weathering profile is well developed, the design and execution of the boxcut can involve significant effort, with the objective of minimizing the volume of the boxcut, whilst ensuring that conditions at the design depth are suitable for establishing a stable portal. Properly designed site investigations are a critical part of this process. Currently available portal design guidelines have not been updated for decades, however the equipment and ground support systems have changed significantly in recent years. Many mine portals have since been constructed in a relatively short time frame with success, often in challenging ground conditions using some of the more modern approaches to ground support. This is beneficial because delays in establishing a portal will generally delay other critical path activities, and lead to cost overruns.

Mar 15, 2021

The effect of superficial gas rate distribution (Jg profile) on down-the-bank metallurgical response was tested in the rougher-scavenger bank (eight 10-m3 tank cells, 4 roughers and 4 scavengers) at Highland Valley Copper Mine's Cu/Mo separation circuit. Three Jg profiles were tested: (a) as found (i.e., typical practice), (b) increasing decreasing (i.e., increasing from cell 1 to 4 and decreasing from cell 5 to 8), and (c) decreasing-increasing (i.e., decreasing from cell 1 to 4 and increasing from cell 5 to 8). The Jg profile approach proved to be of considerable value. Profile (b) gave the best metallurgical results, i.e., the highest down-the-bank grade/recovery (increase in grade at constant recovery was approx. 3-4% compared to the as found case) and the most efficient Cu/Mo separation (cumulative Cu recovery was reduced by almost half - approx. from 20% to 12%, at 99% Mo recovery). The success of the evaluation prompted the implementation of profile (b). Detailed gas dispersion characterization tests (Jg and Db (bubble size)) showed significant discrepancies between the Jg measured directly (using the McGill University sensor) and the Jg calculated from field instrument readings (volumetric gas flowmeter) and machine dimensions (cell cross-sectional area). Tests were designed to reveal the source of disagreement. It was observed that a significant number of bubbles were not able to float (i.e., they were entrained with the tailings), the evidence appearing to be a significant number of very small bubbles (approx. 200-300 µm) which did not have sufficient buoyancy to rise. Consequently, rather than relying on the field instrument, the evaluation depended on the McGill University Jg sensor, which collects bubbles in a tube near the pulp-froth interface, thus providing significance to the data as the measurements were obtained from bubbles that almost certainly floated.

Jan 1, 2007

With the change in legislation under the Resource Management Act 1991 (RMA), the responsibility for administering the effects of blasting on the environment, has transferred from an essentially central government system to local bodies. This naturally will allow for a variety of compliance levels and control procedures which will depend on the particular local body and rather ad hoc arrangements. It is anticipated that the existing NZ Standard on blast vibration levels will soon be replaced by the Australian Standard. These changes raise the question as to what should be used as suitable compliance levels to prevent damage to structures. The paper will address the measurement, control levels and the appropriateness of current standards in relation to the overall legal framework of the RMA.

Jan 1, 1996

By M Burdick, A Harding, M Krulc, M Chappell

Substantial schedule advantages can be made on projects if cross-passage construction can occur at the same time as tunnel boring machine (TBM) operation with little or no impact on TBM logistics. However, this approach can prove difficult to achieve with many of the more cost-effective means of supporting the segmental lining during cross-passage break-out. This paper discusses the constraints and shortcomings of conventional approaches, and describes how a cost-effective solution involving a shotcrete shell and opening constructed inside the segmental lining was designed and constructed to deliver cost and time savings on Seattle University Link contract U220.The paper explains the spatial and schedule constraints on the TBM tunnelling and cross-passage construction, and how a shotcrete solution was arrived at in preference to traditional approaches. As the solution was novel the design had to be robust, and the paper explains how this was achieved through a combination of 3D finite element modelling and closed form solutions. Following a description of the trials to verify that the structure could be demolished post-cross-passage completion, the paper describes how the shell solution was constructed, used and demolished safely to leave the lining surface in a clean and undamaged state fit for tunnel operation.CITATION:Harding, A, Chappell, M, Burdick, M and Krulc, M, 2014. Opening supports to segmental linings – a novel shotcrete support solution, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 267–274 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Robert F. Droullard

The Bureau of Mines has investigated techniques of using gross alpha or beta detectors to continuously measure working levels. Both methods measure radioactive particulates collected on a filter paper using a constant airflow. Inherent-error studies indicate a value of about ±3 percent for the gross alpha method and about ±8 percent for the beta method in typical mine atmospheres. However, the beta method avoids problems associated with alpha detectors and is therefore more useful. Applications of these continuous working-level detectors include work area monitoring of exposure levels in underground openings, such as mines and caves, and calibrating personal dosimeters exposed over extended time intervals.

Jan 1, 1977

Albert Ladd Colby, New York, N. Y. (communication to the Secretary†):—I observed (Trans., xxxvii., 585) that to obtain tenders from several American mills, the foreign engineer should modify his maximum phosphorus to 0.10 per cent., not as Mr. E. Windsor Richards quotes me, that no American rail-maker can produce rails under 0.10 per cent. of phosphorus. Mr. Richards claims that no English engineer would agree to accept 0.10 per cent. of phosphorus on any terms whatever. Mr. Webster writes that only after an engineer has .been convinced that rails can be made in America equal in every respect to those he is getting abroad, should he be asked to modify ally conditions in his specifications. I know it to be a fact that during recent years in many cases, as, for instance, When delivery could be secured more promptly in the United States than in Europe, the consulting engineers of several British and colonial railroads have frequently agreed to modify their phosphorus requirement to a maximum of 0.10 per cent., and the rails delivered' under these modified specifications have, under like conditions, given just as satisfactory service and proved to be no more brittle than similar sections of 0.07 per cent. phosphorus rails, rolled in England under the same specification except without modification as to phosphorus. Furthermore, it would appear from the analyses of British rails, quoted by E. A. Dancaster,2 in his discussion of Mr.

Jan 1, 1908

By R Kjar

Globally, it is anticipated that the mineral sands industry will enter a period of short supply. Demand for both titanium dioxide and zircon is forecast to continue increasing, with new projects needed to come on-stream to fill the supply gap. Victoria is well placed under this scenario as a source due to the high quality of its mineral assemblage, its excellent resource grade and the globally significant size of its mineral sands resources.Australia’s mineral sands rich Murray Basin remains under-developed, especially at its extensive Victorian margins. Development to date has not progressed adequately for the reasons of technology difficulty, history of competition with other jurisdictions and the absence of a platform that requires development as a consideration for security of tenure. Victoria’s mineral sands potential is not just about the Murray Basin, in addition, there have been discoveries in the Gippsland Basin and prospective sites in the Gippsland Basin remain under-explored. Key problems included the lack of available ground for potential developers and the intellectual property of solutions to technological problems associated with the fine grained mineral deposits belonging to a previous developer (with patents now expired).As such, the timing is right to re-visit the potential of the Murray Basin as a site for long-term development with high returns based on current and predicted prices.In order to understand why Victoria’s earth resources in general, and mineral sands in particular, remain under-explored and undeveloped, the Department of Primary Industries initiated an internal review of its role in encouraging and supporting investment in the earth resources sector.As a result, the Victorian Government has committed to taking action to encourage effective ground turnover and acknowledges that a new focus on engagement with industry is needed to bring new investment to the State. The revision of the Mineral Resources (Sustainable Development) Act 1990 provides an opportunity for the government to better align its legislative processes with industry project lifecycles and facilitate access to valuable resources that currently remain undeveloped.Victoria has a track record in assisting projects reach development stage. Iluka currently has two operations in the State in addition to its mineral separation plant that is capable of processing HMC from its South Australian operations. Iluka is expected to ramp up its Murray Basin Stage 2 operations with the WRP mine scheduled to come on line in early 2012. Meanwhile, Astron is actively seeking partners for its Donald Mineral Sands project. The project is becoming increasingly attractive given the recent price hike in zircon; Astron has access to an estimated five to 6 Mt of zircon in its Donald WIM 250 deposit.Given its substantial and valuable mineral sands endowments, the State of Victoria should sensibly be the centre of future investment in project development. However, as previously mentioned this is currently not the case. The Government is therefore committed to implementing new measures that protect security of tenure but ensure that genuine companies can access endowments where they have a clear intent to work those resources.

Oct 5, 2011

By Joe M. Bryan, George E. Rodger

The development of small precious metal mines in the western states has been directed at heap leach operations. Crushing plants are an essential adjunct to heap leach operations. They must meet environmental air quality regulations which generally follow a similar pattern from state to state. Prior to mine construction a permit must be obtained and an operating permit granted during or shortly after the start-up period. The typical construction permit application consists primarily of drawings, specifications and an explanation sufficient to indicate that the mass of particulate matter entering the atmosphere is below minimum standards. The operating permit may be granted following demonstrations that air emission control equipment or methods comply with information submitted in the construction permit application.

Jan 1, 1987

By Ragnhild E. Aune, Shahid Akhtar, Reza Beheshti

"The potential use of Black Dross (BD) as a raw material for the production of refractories, fluxing agents and glasses is the main motivation of the present study. Heat treatment experiments were carried out in Ar, and under reduced pressure (20 Pa), to evaluate the salt removal efficiency. The chemical composition of the BD after heat treatment was investigated by SEM-EDS and XRD analyses. Based on the present results, it is established that the salt starts to evaporate at ˜1273 K in Ar, and under reduced pressure. The salt removal efficiency in a 20 g sample was found to increase in both cases as a function of time and temperature. Moreover, in Ar the chlorine concentration was lowered to 0.3 wt% after heat treatment at 1523 K for 10 hours. Under reduced pressure, however, 0.2 wt% residual chlorine was obtained after 8 hours at 1473 K.IntroductionIt is believed that aluminum recycling in the near future will become the main route of aluminum production [1]. Black dross (BD) that is produced during this process contains, among other things, high amount of salts like NaCl and KCl [2, 3]. Almost 800,000 tons of BD is annually land filled in United States and this number continues to grow with the increase in aluminum recycling [2]. The BD should be dumped in controlled land field and it is costly procedure [4, 5].The water-soluble compounds in BD react with water or environmental humidity and release chlorides into the water and/or generate toxic gases such as H2, CH4, NH3 and H2 S [6-8]. In the Europe, BD is considered as toxic waste and its disposal as landfill is forbidden [8, 9]. After salt removal, the BD is considered to be non-hazardous and can be buried under ground [10].On the other hand, BD do also contains many relatively valuable compounds that may be changed in to useful materials as a result of further treatment [11, 12]"

Jan 1, 2012

By G. W. Jones, R. E. Kennedy

A simple , quick, and relatively accurate device is needed for determining the presence of very small concentrations of organic halide gases in various atmospheres . Such a device would enable safety engineers , health officials , and others to discover quickly the presence of these gases in a suspected atmosphere and thus be able to apply protective measures promptly. This detector should prove useful in detecting leakage of halide gases from refrigerating and air - conditioning systems and in determining the presence of halide solvents in the atmosphere of dry - cleaning and degreasing establishments where organic halide solvents are used . Virtually all poison war gases are halide compounds . Because of the high toxicity of these gases , even in very low concentrations , a detector having the proper sensitivity should be useful in civilian defense for determining when atmospheres are relatively free of poison gases .

Apr 1, 1943