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By F. J. Perzak

The Bureau of Mines conducted a study to develop a standard fire test for 5-gal containers used for storing combustible fluids in underground coal mines. A standard test method was developed which evaluates the performance of the container in a 4-min tray fire. Bureau investigators used the standard test method to evaluate several types of closed 5-gal plastic and metal cans in outdoor tests. Each can tested contained 1 gal of nonfire-resistant (NFR) hydraulic oil. A container failed the test if it lost its contents in any of seven trials. Contents spilled either as a result of thermal rupture or melting. Fewer than 10 pct of the metal containers failed this criterion, but all the plastic containers failed. The metal container failures were usual-ly due to tipping over during pressure relief, which spilled the NFR oil. Replacing the NFR oil in the container with kerosene resulted in failure of more than 30 pct of the metal containers. The standard tests and preliminary tests showed that plastic containers are not equivalent to metal containers in their ability to contain combustibles such as lubricants and greases in a fire. For solvents and lubricants more volatile than NFR hydraulic oil, approved metal safety containers are recommended.

Jan 1, 1985

By K Ehrig, V Liebezeit, E Macmillan

The results from metallurgical test programs are used in feasibility studies for design of new plants and brownfield expansions, in long term mine plans, and to make decisions in an operating plant. There are many elements which contribute to a well-constructed test work program. Ultimately, understanding the accuracy and precision of the test work results is critical to ensuring good decision-making at various phases of a project.Every resource drilling and associated assaying program will have a quality assurance / quality control (QA/QC) component, however this often seems to be overlooked in metallurgical testing programs. The principles of “international standard” or “certified reference material” samples and replicate/duplicate testing can be applied to metallurgical programs, although there are metallurgical-specific considerations in both generating and analysing the data.This paper will describe the QA/QC program carried out within the Olympic Dam geometallurgy program. It will present results in the form of case studies from ten years of testing of replicates and bulk reference samples for industry-standard comminution tests as well as laboratory flotation and leaching tests. The Olympic Dam geometallurgy quality control program has enabled quantification of the precision of metallurgical testing and improved our understanding of the best possible modelling results given the underlying dataCITATION:Ehrig, K, Liebezeit, V and Macmillan, E, 2017. Metallurgical QA/QC – who needs it? The Olympic Dam experience, in Proceedings MetPlant 2017, pp 31–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 11, 2017

By G. Jandieri

An improved methodology is presented for assessing the economic feasibility and effectiveness of recycling industrial waste. The methodology is based on the break-even control mechanism, but at the same time provides for the introduction of new evaluation criteria such as the threshold of conditionality and the degree of ore substitution. Based on an improved analysis, it becomes possible to more precisely predict recycling efficiency. A more refined determination of the lower limit of concentration of recoverable metals, at which technogenic waste can be assigned the status of secondary raw materials and processed profitably, leads to a significant expansion of the secondary raw material base suitable for recycling. The potential for recycling manganese-containing dust from the production of ferrosilicomanganese, dehydrated sludge from the hydro separation of slags, and cake from the production of electrolytic manganese dioxide at the Chiatura mining enterprise is used as an example. It is shown that with a threshold of –24% Mn content, the highest recycling efficiency can be achieved by the production of low-phosphorus manganese slag and conversion to ferrosilicomanganese using the above waste to replace 40-60% grade III and IV manganese concentrates in the feed.

Jan 26, 2023

By James P. Odendahl

Missouri is a state rich in mineral commodities. There is a variety of types of mining as well as minerals in the state. Different phases of mining are controlled by a variety of state and federal laws. What I hope to do today is to present briefly some of the interaction and interplay that has occurred in the recent years between the mineral industry and the Missouri regulatory agencies, as well as some of the interactions by federal agencies. First a little history which dates back to the late 1600's. For many years Missouri has been a leader in the production of lead and zinc. In fact, recent studies have indicated that Missouri produces better than three-fourths of the nation's present lead supply. Less well known but important resource is iron mining. Some of these operations were the source of confrontation during the Civil War. Major battles were fought in and around Ironton, Missouri where iron mining has occurred for many years. One of the largest pelletizing operations in the state is currently located within the city of Ironton. Joplin, Missouri, the home of Thomas Hart Benton, the famous Missouri painter, has a history of lead and zinc mining, going back to the later 1800's. Many of the paintings by Benton contain reference to the early days of mining in Missouri. There is a Benton mural in the City Hall at Carthage depicting the early days of lead mining in that area. Later, the center of lead mining moved to southeast Missouri near Bonne Terre and Flat River. The names of the towns in this area reflect the history of mining, examples - Leadington, Old Mines, Rivermines, etc. The history of lead mining in Missouri has been referred to in some detail in various publications(l).

Jan 1, 1977

By J. R. Sims

Gold assays from production blastholes in the Mercur Hill Pit were used to delineate known ore zones and to determine how well previous exploration drilling defined these zones. The most important factors causing inadequate ore zone definition were: 1) inappropriate location of drill holes relative to the ore zones, 2) presence of stopes from previous mining, 3) sampling and assaying errors, and 4) smoothing of the ore zone boundaries during ore reserve estimation. Infill drilling strategies were evaluated to determine the efficiency with which a given drill pattern defined the known ore zones. A drilling strategy was developed which improved ore zone delineation when compared to techniques which maintained uniform drill spacing.

Jan 1, 1992

By R Fanni, D Reid, M Kulessa

Recent updates to Australian industry guidelines emphasise the importance of the assessment of liquefaction potential of tailings. This includes assessment of the cyclic liquefaction potential, and the post-seismic strength of tailings expected to undergo strength loss from seismic loading. Despite this increase in focus, a relatively small number of Australian tailings appear to have been characterised through cyclic and post-cyclic testing. This paper presents the cyclic characterisation of four Australian tailings, consisting of iron ore, lateritic nickel, vanadium and bauxite residue. Material was obtained either from surficial tube sampling or through remoulding samples in the laboratory from slurries. Testing consisted of monotonic, cyclic and post-cyclic tests for each material. For three of the materials, laboratory-scale shear vane testing was also performed to provide a comparison to post-cyclic strengths from direct simple shear.The results indicated cyclic resistances consistent with the results of other tailings presented in the literature. The lateritic nickel tailings provided the greatest cyclic resistance of the four materials tested, followed by the vanadium tailings. This was somewhat consistent with expectations for material behaviour based on index properties. Post-cyclic strengths were seen to decrease as cyclic strains increased, consistent with typical observations in the literature. Following significant cyclic straining, in some instances the post-cyclic strengths approached those obtained through residual shear vane testing. This provides further insight into the strain-dependent nature of post-cyclic strengths for some materials. The implications of these observations on the post-seismic stability condition are discussed.CITATION:Reid, D, Fanni, R and Kulessa, M, 2015. Cyclic and post-cyclic behaviour of four Australian tailings, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 207–214 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By M. E. Tyrrell

This Bureau of Mines investigation was made to determine the possibilities of using Florida beach-sand concentrator wastes in ceramic products. Sands used in the investigation originated in the Trail Ridge area of Florida, where continued operation of processing plants for recovering titanium minerals promises a dependable source of raw materials. Three general classes of ceramic products were studied, namely: (1) Structural, (2) refractory, and (3) electric-furnace slags.

Jan 1, 1956

By C. Vass, A. Noble

"The chemical treatment of mine-influenced waters is a longstanding environmental challenge for many coal operators, particularly in Central Appalachia. Mining conditions in this region present several unique obstacles to meeting NPDES effluent limits. Outlets are often located in remote areas with challenging terrain where conditions do not facilitate the implementation of large-scale commercial treatment systems. Furthermore, maintenance of these systems is often laborious, expensive, and time consuming. Many large mining complexes discharge water from numerous outlets, while using environmental technicians to assess the water quality and treatment regime multiple times per day. As an alternative solution, this paper describes the ongoing research and development of automated chemical treatment systems for mine water discharges. The current work explains the development of a bench-scale prototype that has been used to evaluate various monitoring, notification, and control strategies. Results from this testing are compared to present day practices to show the costs and benefits of implementing an automated treatment and monitoring program. INTRODUCTION Background The National Pollution Discharge Elimination System (NPDES), per Section 402 of the Clean Water Act, requires permitting of all point source discharges from coal mines. This program dictates that all water leaving a permitted boundary, whether it be process water or storm water, must leave through a monitored NPDES outlet. These permitted NPDES discharge points, also denoted outlets, outfalls or monitoring points, must meet a rigorous set of effluent limits to maintain compliance. Common effluent limits monitored by coal companies include but are not limited to iron, manganese, aluminum, total suspended solids (TSS), and pH. Raw mine water is often deficient in meeting these effluent limits, and as a result, various treatment processes are required to bring the water into compliance prior to environmental release. Depending on the mining and geologic conditions, water monitoring and treatment programs can constitute a significant operating cost for the mine operator. In Appalachia, acid mine drainage (AMD) constitutes one of the most significant and widespread water quality challenges that must be treated per NPDES guidelines. AMD is a general lowering of water pH that occurs when water and sulfide minerals interact within oxidizing conditions in coal and metal mining. Acid Rock Drainage (ARD) is a similar term that applies more generally to non-mining causes such as highway construction and other large-scale excavations. Today, mine influenced waters (MIW) is becoming more popular as the general term referring to all types of mining-induced water issues. AMD has been researched substantially over the last 30 years, with investigators studying various causal mechanisms and treatment strategies (e.g. Gazea, 1996; Ziemkiewicz, 1998; Skousen, 2000; Kleinmann, 2001; Johnson, 2003; Akcil, 2006; Kalin, 2006). This research has produced several pragmatic results, which provide numerous methods to predict, prevent, and treat AMD."

Jan 1, 2016

By M. Rotz

In the minerals industry today, the ?low hanging fruit? that once existed to debottleneck production and improve recovery, while meeting market needs for quality in mineral processing operations, are more and more difficult to find. Systematic methods for establishing plant mass flow, recovery, operational efficiency and control strategy in context with customer specifications provides the necessary insight and confidence for plant operators to prioritize improvement projects in order to maximize return on investment (ROI) for the site. The evaluation of aggregate and industrial mineral processing plants requires the following steps when projecting cost saving opportunities: collecting background data, conducting a base-line evaluation, analyzing specific unit-operation performance, defining investment options, prioritizing the selected improvement opportunities and the implementing process changes. The following paper describes the approach and challenges of developing an improvement plan for a dry and wet mineral processing operation.

Feb 23, 2014

By O. Babak, O. Leuangthong, M. A. Cuba

Integration of data from multiple sources and/or multiple scales is a common, yet challenging aspect of geostatistical resource modeling. Common approaches to data integration are based on a cokriging framework that assumes a consistency of scale in the information that leads to a requirement to composite the data prior to model construction. It is well known that the geostatistical model parameters are scale dependent. In particular, the volume variance of integrating these various scales has a direct impact on the semivariogram that should be used in model construction and/or the assessment of volume-variance relations as it affects resource estimation. This paper reviews and compares two different approaches for semivariogram upscaling. The first approach is the scaling laws. It is an empirically derived approach, involving several simplifying assumptions, one of which is a strict assumption of invariance of the semivariogram shape. The second approach is a theoretically derived direct upscaling of the semivariogram. This approach has been around for a number of years, but is seldom implemented due to software limitations. In this paper, we present a numerical integration approach to facilitate direct semivariogram upscaling. The advantage of direct upscaling over the scaling laws approach is shown by considering a synthetic example and a case study. Further, in the case of multiple codependent random variables, the extension of the direct semivariogram upscaling to the cross semivariograms is derived and an upscaled consistent linear model of coregionalization is presented.

Jan 1, 2013

By Frederick B. Kuhnow

Harmonic energetic delamination of T2 building is being considered for demolition at a formerly known atomic lab. The T2 building is within a containment structure that is under a negative pressure of -49 Pa (-0.2 inches of WC) so that no remaining radioactive material is leaked out. The T2 containment enclosure is a portal frame-type system that spans east/west over 35.05 m (114’-11 7/8”) and spaced 2.9 m (9’-6”) apart. The west side of the portal frames is supported by a 64 cm (2’-1”)thick concrete wall which is backfilled to the west and open to the T2 basement to the east. The east side of the portal frames is supported by a 61 cm (2’-0”) thick concrete wall that is backfilled to the east and open to the tank farm vaults to the west. A concrete slab-type footing supports both the east and west walls. Transverse walls provide lateral support for the walls as part of the original design. The west wall has an elevated slab that provides further stiffening of the concrete wall between the transverse walls.

Jan 1, 2017

By Pier Francesco Paglini, Gian Luca Menchini, Pier Francesco Boschi

"PROJECTThe “Caltanissetta” Tunnel is part of the ANAS S.p.A (National Autonomous Roads Corporation) $ 1.3 Billion Highway 640 Caltanissetta-Agrigento (Sicily, Italy) Rehabilitation Project, consisting in upgrading of 62 km (40 miles) of highway. The Italian multinational construction company Cooperativa Muratori & Cementisti di Ravenna, is the General Contractor for the design and build contract. The highway S.S. 640 starts from Porto Empedocle, to the intersection with the Motorway A 19 Catania-Palermo.The entire project, double carriageway designed for speed 70-120 km/h and maximum longitudinal slope of 4.2%, is divided into two sections. First Section: just finished and opened to traffic. Second Section: mainly involving the province of Caltanissetta, length about 28 km (18 miles), works started in 2013. This second section includes the most challenging work of all the project, the “Caltanissetta” tunnel consisting of two separate tubes, each with 3.9 km length and inside diameter of 13.50 m, in order to host 2 traffic lines and an emergency line. HORIZONTAL AND VERTICAL ALIGNMENT - GEOLOGY AND HYDROGEOLOGYThe plan alignment of “Caltanissetta” tunnel is formed by two tubes which are located at a minimum mutual distance of 22 m to a maximum of 63 m, with n. 9 pedestrian and n. 4 road cross passages; ventilation shafts are not provided. Overburden over portals area is about 5 m till a maximum of 120 m. Tunnel sections have variable longitudinal slope from 2.6% to 0.5%, transversal slope of about 3.5%. Right tube length is 3,992 m, left tube length is 3,877 m."

Jan 1, 2016

By Anuradha Khetwal, Tala Tahernia

The estimation of TBM utilization rate can be problematic due to the uncertainty involved in the tunneling system reaction to various geology along the tunnel. Moreover, the impact of operational and management issues on TBM performance is unsettled. This includes the occurrence and duration of downtimes and the uniqueness of projects relative to the geology, machine type, backup system, site setup, crew experience, and operational restrictions imposed on the project by localities. The CSM2020 is a model based on discrete event simulation that predicts machine utilization for single or double shield TBM. This model was developed by the Earth Mechanics Institute (EMI) team, using the database of tunneling activities which was compiled based on field observation and measurements in pertinent projects. In the current study, CSM2020 was modified to simulate the workflow of slurry TBMs. The operating principle of slurry shield TBMs is different than open-mode TBMs. The model was verified by comparing results with a recently completed project in the United States. As a result, the model offers reliable utilization rate estimation in different types of TBM by implementing appropriate workflow.

Dec 1, 2022

By J. S. Gardner

Fortunately, few mining professionals have dealt with what all mining professionals fear---a mine disaster. Unfortunately, many have dealt with ?accidents? which may or may not claim lives but nevertheless rise to the level of a ?disaster? given the fallout of liability and litigation in today?s society.1 The undersigned authors published an article some ten years ago regarding crisis management2 based upon their collective first-hand experiences in actual disasters to that point in history. Unfortunately, disasters have occurred since that time, prompting legislation, and a fresh analysis and expansion of those basic principles is certainly in order. Without question, no two disasters are ever alike, yet general guidelines for forming an effective plan of action can be formulated?and if a mining operation is to have any chance of survival after a disaster, such a plan is vital. The primary concern as any disaster evolves remains as stated a 2003 SME article3--the protection of human life. From that point, the focus moves to any assistance that may be needed given the magnitude of the situation. Permeating throughout this process is "damage control." The first step in dealing with a disaster, however, begins long before any threat of danger arises?formulation and implementation of an Emergency Response Plan.

Feb 23, 2014

By A. Bozorgzadeh, B. M. Jensen, B. N. Koelling, B. R. Murtaugh

"The Service Base mooring system originally consisted of two general types of structures, 19 timber piles cabled together and steel three-legged pipe piles. The St. Louis District fleet moored to the fleet barges which were tied off to shore-side concrete deadman and supported on the landward side by the timber and steel piles. The purpose of this project was to replace the existing floating wharf mooring system at the St. Louis Service Base. The Marine Design Center of the U.S. Corps of Engineers developed a three pile cluster system concept. The clusters consisted of one vertical pile and two batter piles. Piles in rock sockets were selected to resist the uplift loads due to high wind loads on the tall, spare lock gates stored at the floating wharf. This paper focuses on the design of the rock sockets for steel pipe piles with large uplift loads and the lessons learned during the design and construction of this system.INTRODUCTIONBackgroundThe U.S. Army Corps of Engineers’ St. Louis District is located at the critical transition point on the Mississippi River where it is a “locking river” north of St. Louis and an “open river” to the south. The St. Louis District is responsible for maintaining navigation channels on the Mississippi River, the Illinois River and the Kaskaskia River. It is also responsible for the operation and maintenance of five locks and dams within its geographic boundaries.The St. Louis District utilizes a fleet of vessels (dredges, crane barges, motor vessels, and barges) to support the navigation mission identified above. The St. Louis District Service Base, located in St. Louis, Missouri, serves as the base of operations for the district fleet. This riverfront facility originally consisted of a floating wharf, a railroad trestle, and a walkway down the river bank to the floating wharf. Historically, there have been two fleeting areas at the Service Base. The main fleeting area was approximately 965 feet long and consisted of six fleet barges (Figure 1). This area supported the Dredge Potter and its attendant fleet. The upper fleeting area was approximately 1,050 feet long and consisted of various stop log, crane and work barges, dredge pipe pontoons and work flats."

Jan 1, 2017

By T. J. Langan, M. Ramajayam, T. Dorin

"6xxx-series Al alloys are the most commonly used alloys in the automotive industry as they have an appropriate balance of strength, corrosion resistance and formability. The main strengthening phase in these alloys is the ß’-Mg2Si precipitates. One opportunity to achieve stronger 6xxx-series Al alloys, without affecting corrosion and formability, is the use of Sc. The main challenge of using Sc in 6xxx-series lies in the heat treatment, which must be designed to allow for a fine precipitation of both Al3Sc and ß’-Mg2Si. In this work, two model alloys are used, an Al-Sc-Zr and an Al-Mg-Si-Cu-Sc-Zr, to explore the impact of the 6xxx-series key elements (Mg, Si and Cu) on the Al3Sc precipitates. Transmission electron microscopy and atom probe tomography are used to investigate the precipitates present in the microstructure after casting. We find that higher Si content results in the formation of dispersoids upon casting. The average composition of these dispersoids is (Al0.8,Si0.2)3 (Sc0.888,Zr0.024,Mg0.08,Cu0.008). A closer look at the solid solution reveals that most of the Sc and Zr is supersaturated after casting even in the presence of Mg, Si and Cu. We discuss the impact of these results on the design of a suitable heat treatment for 6xxx-series alloys with Sc.INTRODUCTION The most common strategy to strengthen aluminum (Al) alloys is by micro-alloying to form a fine distribution of precipitates (Gladman, 1999). Whilst precipitates enhance the strength, this is often done to the detriment of ductility and corrosion performance (Davis, 1999). The 6xxx-series Al alloys are heavily used in the automotive industry as they offer an appropriate balance of strength, ductility and corrosion resistance (W. S. Miller et al., 2000). The strength increment in these alloys comes from the formation of the ß’–Mg2Si and the quaternary Q’ phase (Chakrabarti & Laughlin, 2004; Polmear, St. John, Nie, & Qian, 2017). One opportunity to achieve stronger 6xxx-series alloys, whilst keeping good balance of corrosion resistance and formability, is the use of small additions of scandium (Sc). Sc is one of the most potent strengtheners in Al alloys (Dorin, Ramajayam, Vahid, & Langan, 2018; Røyset & Ryum, 2005). Most of the strengthening benefits from Sc come from the formation of fine Al3Sc dispersoids. The following strengthening mechanisms apply to Sc: 1) Solid solution strengthening, 2) precipitation hardening, 3) inhibiting recrystallization, 4) assisting nucleation of other strengthening phases (Dorin, Ramajayam, Lamb, & Langan, 2017). As compared to other dispersoid phases, Al3Sc dispersoids have good electrochemical compatibility with Al alloys and hence do not affect their corrosion resistance (Cavanaugh, Birbilis, Buchheit, & Bovard, 2007). The coarsening resistance of Al3Sc is often improved by adding zirconium (Zr), as it forms a Zr rich shell around Al3Sc which prevents Sc from moving across the interface."

Jan 1, 2018

By Francoi Robert, Andre J. Audet, Alex C. Brown

"The Sigma gold deposit is in a band of deformed metavolcanic rocks that are cut by an irregular mass of porphyritic diorite and by narrow undeformed feldspar porphyry dykes. The gold is in veins consisting mainly of quartz and tourmaline with minor pyrite, carbonate, chlorite, scheelite and free gold. The results presented here concern the structural setting of the ore and are based on a study of the mode of emplacement.Two principal types of veins have been recognized: subvertical and oblique veins. Both types are contemporaneous, mechanically linked and postdate regional deformation. The sub-vertical veins are composed of numerous mineralized lenses that occupy the central part of ductile shear zones of great lateral and vertical extent. Normally, several lenses occur in the same shear zone. The vein material seems to have resulted from incremental filling of openings by repeated vertical movement along rupture planes developed in the central part of the shear zones.The oblique veins are small elliptical lenses of ribboned vein material which formed essentially by progressive vertical opening of oblique fractures. Two types of oblique veins are known: one is restricted to feldspar porphyry dykes, within which they are arranged in an en-echelon fashion; the other is of greater extent and is not restricted to one rock type, but tends, however, to occur in the more competent porphyritic diorite.Vein orientation and mode of formation suggest that both sub-vertical and oblique veins developed during progressive deformation associated with the formation of the ductile shear zones. The latter probably formed in response to a compression that took place late in the tectonic history of the host rocks at Sigma."

Jan 1, 1983

By Francoi Robert, Andre J. Audet, Alex C. Brown

"The Sigma gold deposit is in a band of deformed metavolcanic rocks that are cut by an irregular mass of porphyritic diorite and by narrow undeformed feldspar porphyry dykes. The gold is in veins consisting mainly of quartz and tourmaline with minor pyrite, carbonate, chlorite, scheelite and free gold. The results presented here concern the structural setting of the ore and are based on a study of the mode of emplacement.Two principal types of veins have been recognized: subvertical and oblique veins. Both types are contemporaneous, mechanically linked and postdate regional deformation. The sub-vertical veins are composed of numerous mineralized lenses that occupy the central part of ductile shear zones of great lateral and vertical extent. Normally, several lenses occur in the same shear zone. The vein material seems to have resulted from incremental filling of openings by repeated vertical movement along rupture planes developed in the central part of the shear zones.The oblique veins are small elliptical lenses of ribboned vein material which formed essentially by progressive vertical opening of oblique fractures. Two types of oblique veins are known: one is restricted to feldspar porphyry dykes, within which they are arranged in an en-echelon fashion; the other is of greater extent and is not restricted to one rock type, but tends, however, to occur in the more competent porphyritic diorite.Vein orientation and mode of formation suggest that both sub-vertical and oblique veins developed during progressive deformation associated with the formation of the ductile shear zones. The latter probably formed in response to a compression that took place late in the tectonic history of the host rocks at Sigma."

Jan 1, 1983

By V. D. Tathavadkar

Chromite ore is of immense importance for the extraction of metallic chromium and chromium chemicals. The mineralogy and crystal structure of chromite phase are therefore important part of our investigation on the extraction chemistry of chromium species. In this investigation, we have studied the effect of the processing parameters, i.e., the temperature and the oxygen potential on the microstructure and composition of mineral phases formed in the Cr2O3 ?Al2O3 -FexOy -MgO system. In particular the importance of the spinodal decomposition reaction is emphasized in the extraction of chromium as sodium chromite and sodium chromate. Experiments were carried out in order to study the differences in the crystallography of different chromite minerals. Phase equilibria in natural chromite minerals were investigated by calcining chromite mineral in air, argon, and 5% hydrogen + argon atmospheres over a temperature range from 200 to 1200 °C. The effect of the oxygen partial pressure and temperature on the phase constituents of the calcined product has been discussed. The microstructural changes were examined using scanning electron microscope (SEM) and the changes in elemental composition in different phases were analysed by electron probe micro analyser (EPMA). The results obtained from EPMA studies were used to calculate lattice parameter of the spinel lattice, and these values were compared with the values obtained from X-Ray powder diffraction data. On the basis of the experimental data, the mechanism of the spinodal decomposition of complex spinel phases is described under the influence of oxygen partial pressure and temperature.

Jan 1, 2000

By L. C. IlsLey

[The service given by a flame safety lame is twofold: It provides a safe light and it gives evidence of the condition of the mine atmosphere relative to the presence of methane and the deficiency of oxygen. Since the development of portable electric mine lamps, flame safety lamps are little used for lighting but their use as detectors is as extensive and important as ever. A flame safety lamp in the hands of a trained user will definitely show methane concentrations as low as 1 percent, which in well below the lower explosive limit of methane and air. However, this does not always suffice, especially when making studies of mine ventilation, where it may be desireable to detect concentrations below 1/2 of 1 percent.]

Jan 1, 1936