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By Fred Perea

The practical example of the effectiveness and necessity of establishing and maintaining close communications between the design engineering section and operating section of a large plant concerned with the building of an underground crusher will be presented.

Jan 1, 1969

"What is your history and how did you get involved in mining?Like many SME members, I came from a mining community with a family history in mining, in my case Walkerville, MT. Both of my grandfathers were underground miners. My father was a miner for a short time. He later sold drinks to the miners. Unfathomable by today’s standards, my dad would pick up the miners’ checks at the pay office and have them cashed and waiting with a shot and beer for the miners when their shift ended. My mother was a nurse, who from time to time, would patch up an unfortunate miner. I remember walking past multiple picket lines on the way to and from grade school, watching homes being boarded-up. I grew up with a deep respect for the critical relationship between labor and management.I had no intention of going into mining and initially set out to pursue a career in chemical engineering. But I attended my first two years of engineering at Montana Tech, due to the proximity and affordability. This is where I met Dr. Tom Finch, a mining professor who taught statics to the engineering students. After a coaching session in a hallway, half way through my sophomore year, I switched to mineral processing engineering. In his colorful way, Professor Finch advised me that, “You do not want to make #@*!! erasers and #@*!! Jell-O the rest of your life go talk to the guys in mineral processing.” He was very persuasive and here I am today.How about your involvement with SME?I encountered SME out of school and a little later in my career. Terry Maio and Jim Arnold invited me to local section meetings in the Missouri Lead Belt. That was my first exposure to the technical programming and relationship building that was possible at the local level. After Ozark Lead shut down and I relocated to Nevada, Rich Johnson, Scott Barr and Dave Collins encouraged me to attend my first annual meeting in Salt Lake City, UT. I joined SME at that time and was fortunate to be engaged by members like Art Schweizer and Jim Arnold, and I soon began the leadership progression for the Mineral & Metallurgical Processing Division. Since then, I have supported SME at the national and the local level serving in multiple roles and capacities."

Mar 1, 2017

By James E. Jones

The coal mining industry is being called upon to vastly increase production in the coming years. Many mining operations will have to prepare an environmental impact report of some kind and all will have to comply with various types of environ- mental regulations. Therefore there is a great need within the industry for access to environmental data, information, and literature. This paper discusses the informational resources available, the current lack of access to these resources, and the Environmental Data, Information and Literature (EDIL) Bank of the Kentucky Institute for Mining and Minerals Research. The bank's major emphasis concerns the environmental, social and economic aspects of producing clean solid, liquid, and gaseous fuels from coal. The data bank promotes information interchange between other related governmental and private projects and the energy development community.

Jan 1, 1976

By Panshi Xie, Yingyi Zhang, JIANJIE DUAN, Shenghu Luo

The most important safety aspect associated with great mining height in steeply dipping coal seam mining is the stability and control of the roof. When soft coal and hard gangue make up the immediate roof of a working face, the soft-coal interlayer plays a significant role in gangue damage and can cause problems such as roof collapse in front of the support, collapse of partial area supports and other problems that can affect the stability of the supports and the surrounding rock system. This study found that the first weighting step of a multigangue roof is larger than that of a nongangue roof, but periodic weighting steps are similar. The overburden collapse height is lower in a multigangue roof than in a nongangue roof due to the buffering and supporting function of the collapsed gangue. Failure of the coal interlayer is the key factor in the collapse of multilayer gangue. The limited load of the interlayer and maximum resistance of the support is concluded by the hard gangue and soft coal interlayer mechanical model. The maximum resistance of the support increased with the dip angle of the seam and burial depth. Certain measures are proposed to control the stability of the gangue roof, including zoning control of the mining height and resistance and advancing the support while maintaining roof contact, thus ensuring the integrity of the support and surrounding rock system.

By Yueyue Ding, Yuanhui Li, Zhengrong Li, Pengfei Yu, Kunmeng Li, Zhipeng Xiong

The overburden responses in gently inclined orebody mining are different from those in horizontal orebody affected by the orebody dip angle. In particular, the mining-induced stress presents asymmetrical distribution characteristics spatially, resulting in stress concentration and large-scale pressure relief phenomenon in the surrounding rock. As a result, frequent ground pressure disasters such as roof collapse and barrier splitting occur frequently. Moreover, the ground pressure evolution law and the interaction between stopes in multistope mining are complex. The effective ground pressure control measures cannot be taken due to unclear understanding of the evolution of stress and displacement fields, justifying the investigation of the distribution and evolution of underground pressure for safe and efficient mining.

Jun 1, 2023

By Mritunjoy Sengupta

The Green River formations in the Western U.S.A. contains vast amounts of petroleum reserves in oil shale deposits. Exploitation of this petroleum reserve calls for large scale mining of the oil shale. Applicable mining methods include conventional underground mining using roan and pillar, sub-level caving and block caving; underground insitu retorting of oil shale and open pit mining. Roam and pillar mining offers one of the most economic methods of underground mining of oil shale. A 2.4 x l09 litre per year (50,000 barrels per day) of crude oil production would require a daily oil shale production of 100,000 tomes per day from underground operations. For this large production, a highly mechanized room and pillar mining muld utilize large capacity diesel equipment such as 85 tonne trucks and 8m front end loaders. The total air requirements of an oil shale mining operations can. be as high as 28443/s. Ventilation planning for such a large scale underground mining operation presents a formidable task. The major objectives of providing ventilation air to underground workings are to dilute airborne .dust and diesel fumes to harmless levels, and to insure that the mine environment is compatible with the health and safety of mine personnel. Regulation of air velocities and air temperatures is a major factor in mine environmental control. Colorado State law requires that a minimum of 0.047m3/s of fresh air be supplied for each kW of diesel power operating underground. Additionally, 0.047m3/s of fresh air must be supplied for each underground employee, and a minimum air velocity of 0.15m/s must be maintained in all working places. It is desirable to exceed this minimum velocity in order to prevent stratification of ventilation air. Moreover, Colorado law also stipulates the maximum allowable concentration of noxious gases mine air, below: ? C02 - 0.5% by volume, 5,000 ppm. ? CO - 0.005% by volume, 50 ppm. ? Oxides of Nitrogen - 0.0025% by volume, 25ppm. ? Nitrogen Dioxide 0.005% by volume, 5 ppm. This paper examines ventilation requirements for the underground mine, with respect to air quality requirements and distribution of air in mine workings in light of the above regulations. Analyses were made for sane typical mining plans to determine airflow resistance or pressure drops and fan horsepower requirements. In addition, the possible occurrence of high concentrations of toxic gases, was examined. Expected temperature levels in mine workings were approximated.

Jan 1, 1980

By N. Duru

"Gravity concentration is still a challenging area in the mineral industry. This is mainly because of the fine size valuable mineral losses to the tailings during its application. But the recent developments in centrifugal separation methods and their mutual application with conventional separation techniques has increased mineral recoveries. In this paper, field application of conventional gravity separation methods with the combination of 2” diameter hydrocyclone cluster unit and a multi gravity separator (MGS) was discussed. Additionally, particle size distribution and chromite content of the plant streams is presented and initial laboratory test results were compared with the actual plant data throughout the paper. As expected, field data showed derivations from the laboratory tests but the combination of MGS and conventional gravity separation techniques resulted in gravity separation of -0.1 mm chromite particles. INTRODUCTION The purpose of this mineral processing plant project was to investigate the possibility of upgrading chromite ore from 12% to 48% Cr2O3 and having final tailings assay as 2% Cr2O3. For this reason, initially a set of laboratory gravity separation studies were conducted to evaluate the performance of combination of 2” diameter hydrocyclone cluster and multigravity separator. After obtaining successful results from the laboratory work, a feasibility study was initiated. Economical results of the feasibility study showed that an achievable high net present and return on investment values. Following the investment decision; engineering, equipment procurement, construction of the processing plant was completed in eighteen months. This paper focuses on the initial laboratory test work results, operational data of the 2” diameter hydrocyclones and MGS units; resulted chromite recoveries. Processed ore has the chromite associated with serpentine and olivine minerals. The chromite particles are generally in round shapes with sizes between 50 µm to 1600 µm and average size of 450 µm. The microscope images of the chromite and associated formations are presented on Figure 1.Chromite is formed in mixture with iron oxides, with varying amounts of magnesium, aluminum. The average chemical composition of the representative drill core samples of the ore deposit is given on Table 1."

Jan 1, 2017

By Alix Thierart, Yann Rouillard, Bernard Catalano

Bessac's presence in Singapore started in 2014 with the construction of the Thomson metro line, which includes 18 miles of twin-bore tunnels and 22 stations split into 17 construction packages. Bessac joint venture was allotted the T219 lot. The works include the construction of a new 660-foot (200-meter) long transfer station, two parallel 19-foot (5.8 m) ID tunnels and a pedestrian underpass. The urban context and the very soft ground stratum imposed to utilize unusual tunneling techniques, from upgrading a slurry TBM to a high-density slurry TBM to launch with very low cover and canopy pipe roofing completed with a MTBM without retrieval shaft.

Jun 23, 2024

By S. G. McDowell

This paper discusses the utilization of automation to increase productivity of continuous miners. Automation techniques are used during the design stage to decrease the time required and ensure the accuracy of the design. This is followed by automated manufacturing processes to reduce manufacturing time and improve the quality and consistency of parts. Combined, the result is a more reliable machine which can provide ongoing production capability. With the use of automation to enhance operator effectiveness and monitoring machine condition the productivity of machines is also improved.

Jan 1, 1991

By Victor S. Sazhin, Alexander Kostenko

The hydrochemical method, which is based on the separation of aluminium oxide and silicon oxide by the hydrothermal decomposition of aluminosilicates by alkaline solutions in the presence of calcium oxide, can be effectively used for the complex processing of high-silicon aluminium ores. In this case, the silica is bound to a slightly soluble compound: Na20.2Ca0.2Si02•H20 (under the conditions: [&k]= 9, CaO/SiO2 = 1.05, alkali concentration in the solution: over 300 g/l Na20, T = 240...300 °C). If alkaline solutions of 100...150 g/l Na20 concentration are used, Ca0•SiO2•H20 or 2Ca0•Si02.0.5H20 compounds, depending on calcium oxide dosage, are formed at 280...320 °C. New methods for the crystallization of Na20.Al203.2.5H2O from concentrated alkaline solutions rand low-concentration solutions are proposed to isolate aluminium from solutions. The hydrochemical method, which involves no sintering process allows one to decrease the expenditure of heat by a factor of two, to reduce the investment and to exclude the pollution of the ambient air by dust-laden gases. The expansion of the raw-material resources base of

Jan 1, 1984

By William P. Diamond

Production trends have been analyzed for 82 gob gas ventholes on 7 longwall panels in the Lower Kittanning Coalbed, Pennsylvania. Cumulative production from individual holes was found to vary considerably, ranging from 0.03 x 106 m' to 10.1 x 106 m3. Peak production rates were generally about 0.03 to 0.06 x 106 &/d, but rates over 0.10 x 106 m3/d were observed. The variability of gas production from individual holes can be attributed to several factors including: completion practices and problems, the extent of fracture development in the strata above the extracted panel, water production, and location on the panel. Of particular significance, is hole location. Holes on the ends of the panels, where overburden strata are in tension due to the support of the surrounding pillars, were generally the highest and longest producers. This observation led to the experimental placement of gob gas ventholes in the zone of tension along the margin of a panel, instead of in the traditional centerline location which is in compression. Analysis of gob gas production data indicates that the experimental near-margin holes produced 77 pct more gas than did centerline holes on the same panel.

Jan 1, 1995

By R. S. Mateer

Linear programming on desktop computers is commonly used to optimize coal blending proportions. The objective function is usually the cost of the blend. The constraints consist of materials and heat balances as expressed as linear functions of the blend. This is illustrated in Example 1. Inclusion of a sulfur compliance constraint in more complex because the maximum permitted sulfur percentage is not a pre-specified constant. Rather, it is a function of the calorific power of the blend itself. The current limit of 1.2 pounds of sulfur dioxide per million Btu may be expressed as: [Sulfur Max%= 0.6 . Hl10,OOO with H in Btu/lb.] A proper constraint equation may be formed by defining for each coal a function that is the difference between the actual sulfur percentage and the maximum sulfur percentage. This may be regarded us an excess sulfur percentage. For Coal A of Example 1. this would be: [ Sulfur Excess%=0.5-0.6 13,000/10,000=-0.28] This value would be used as the coefficient of the weight proportions of this coal in the blend. The complete constraint equation would then be the sum of such terms for each coal set less than or equal to zero. This is illustrated in Example II. [ ]

Jan 1, 1995

By Phillip Crowson

The annual surveys of corporate exploration expenditures carried out by Metals Economics Group (MEG) show that estimated total spending rose to a record $13.2 billion in 2008 ($14.4 billion including expenditure on uranium exploration). This compares with the previous peak of $5.2 billion in 1997. MEG does not adjust its figures for the effects of inflation but recognizes that the substantial increase in budgets of recent years has not been reflected in a proportionate rise in actual activity on the ground (MEG, 2009). In recent years, costs were boosted by rising prices of fuel and other inputs, and acute shortages of qualified staff and drilling rigs. The inflation rate for exploration substantially exceeded increases in general price levels as measured by national indices. Just how much exploration costs in-creased, however, is probably not widely appreciated. Figure 1 compares the MEG estimates of total annual dollar spending in Australia, Canada and the United States combined with their drilling activity, measured in meters drilled, as reported by national agencies. These three countries accounted for 39 percent of MEG?s estimate of total spending on minerals exploration in 2007 and 40 percent in 2008. Expenditure is shown both in money terms, as reported by MEG, and adjusted to real terms, with the U.S. implicit gross domestic product (GDP) price deflator. The comparison is of index numbers based on 2000 as 100. Comparisons for the individual countries are shown in Fig. 2 to 4. National figures for drilling activity and expenditures cover some minerals like iron ore, coal and industrial minerals (29 percent of Australian spending in 2007 to 2008 and 10 percent of Canadian in 2008) that are not included in the MEG estimates of spending. Such exploration has risen more than the total since 1997 so that the index of drilling activity in the figure may be overstated for recent years on a like for like basis with the MEG data. MEG only includes spending on uranium exploration in recent years whereas the national agencies include it throughout. Figures 5 and 6 com-pare national and MEG estimates for Australia and Canada. No comparable figures are available for the United States. The national estimates have been converted to U.S. dollars at the appropriate annual average exchange rates, and the Australian annual totals have been summed from the published quarterly data. Not only is spending cyclical, but so are unit costs. Australian and Canadian data show that total exploration spending per meter drilled rose by 2.5 to 3 times between 2001 and 2008. These rises may partly reflect increasingly complex drilling methods, and an increased share of assaying and testing in total exploration costs. In Canada, however, diamond drilling accounted for a lower footage of the total in 2005-2007 than in the preceding few years, and spending on exploration, as opposed to deposit appraisal, made up a higher proportion of the total. Figure 7 compares index numbers of exploration spending per meter drilled in U.S. dollars for Australia and Canada. These figures raise a number of questions. First, is the relationship between total expenditure and meters drilled in the three countries for which data are available typical of the global experience? Secondly, has there been a significant change in the make-up of exploration spending in recent years? The Canadian data do not suggest that there has been, but is Canada typical? Has drilling become less important relative to other exploration techniques, or is it just as important as ever in confirming the existence of viable ore deposits?

Jan 1, 2009

By J. S. Hu

FTIR spectroscopy has been used for the characterization of adsorbed oleate at the fluorite surface. It has been found that modest changes in the adsorption density at high temperature and high oxygen potential do not provide a satisfactory explanation for the significant increase in the hydrophobic character of the system under similar conditions. Rather, FTIR spectroscopic measurements suggest that chemical interaction between adsorbed oleyl groups occurs at high temperature and/or oxygen potential and accounts for the increased hydrophobicity. Specifically, the intensity of the =CH bond of the adsorbed oleate diminishes at high temperature and/or high oxygen potential. Such a phenomenon was not observed in control tests with the calcium oleate soap. For extensive reaction at the fluorite surface, the presence of a new surface species has been identified. These results indicate that the fluorite surface catalyzes an oxidation and/or polymerization reaction between adsorbed oleyl groups which results in a more hydrophobic structure at the fluorite surface.

Jan 1, 1986

By R. C. Bunge

Many minerals float best with fatty acids in the intermediate pH range. For example, fluorite, a semi soluble salt mineral, exhibits a maximum contact angle and a maximum flotation recovery in the pH range of 6-8 after conditioning in a palmitate solution (fig. 1). The maximum in flotation coincides roughly, as many researchers have observed, with the boundary of bulk precipitation of the fatty acid. According to fig. Z this boundary is in the above case of 5xl0-7 M palmitate approximately at pH 6.3. For assessing the phenomena occurring at the bulk precipitation boundary of fatty acids, the surface tensions of carboxylate solutions have been measured under various conditions. Fig. 3 shows the surface tension development of palmitate and myristate solutions of increasing concentration at pH 12. Also shown are the bulk precipitation edges (BPE) of the respective solid species that is stable under these conditions, that is the potassium acid soap, HKAZ. Both curves display a similar behavior. As the concentration of carboxylat,e increases, the surface tension decreases, until a minimum is reached at which the curves level off. The decrease of surface tension with increasing carboxylate concentration is generally taken to indicate the surface excess of the carboxylate ion. The point where the curve suddenly levels off has not yet been explained. While it is well known that the onset of micellization (CMC) may cause such an inflexion of the surface tension curve, this cannot be the case here because the position of this point depends, as shown in fig. 4 for palmitate, on pH (the CMC is generally independent of pH). We believe that this point indicates the precipitation of a colloidal acid soap (colloidal precipitation edge, CPE) before the bulk precipitation of this species sets in (BPE).

Jan 1, 1994

By Michael J. Cruickshank

MICHAEL J. CRUICKSHANK SENIOR AUTHOR Marine mining is a very broad field. It encompasses every facet of terrestrial mining but with the unique addition of a superimposed liquid overburden, which is itself mineralized. It is the unique aspects of marine mining that are discussed in this section. In keeping with the times, a systems approach is taken in the presentation of the material. The environment is first described, and this is followed in logical sequence by the common requirements for working there, then the mineral exploration phase, the exploitation and, finally, the operational restraints imposed by man and nature. Free use is made of tables and figures from original and published works and extensive listings of reference material round out each section. The title "Marine Mining" was chosen in preference to ocean or underwater mining because it is broad enough to include oceans, beaches and inland seas. The selection of terms sometimes may seem odd but they have not been chosen arbitrarily. All things are reduced, where possible, to basics and defined. Applying systems terminology, the word "platforms" is used in the functional sense and includes not only airborne, waterborne and fixed platforms, but man himself in his capacity as a working diver. If there is confusion it is often because of familiarity with a word in a context personal to the reader. For example, what does extraction mean to you-or mining or exploitation? Cost data have been interspersed throughout the section whenever they could be obtained. The use of these data should be tempered with understanding because no two situations are alike and improvements in marine technology are constantly being made. The names of individual authors are listed with each subsection. Where no name is given, the responsibility has been that of the senior author. Acknowledgment is sincerely made to the U.S. Bureau of Mines, and latterly the National Oceanic and Atmospheric Administration, for encouraging and supporting the preparation of the work ; to the secretarial staff at the Marine Minerals Technology Center and to Donald Eisman for editing. To the many other contributors who may not be listed by name, grateful acknowledgment is also due. It is hoped that the chapter will be useful to the practicing mining engineer who suddenly is assigned to marine work or to the experienced marine engineer who is equally suddenly assigned to mining work. It is not possible to put "everything-you -need-to¬-know" into one section, but. the very full bibliographies at the end of the text should adequately fill in for those who wish to know more. 20.1-THE MARINE ENVIRONMENT Marine mining is set apart as a separate discipline by the marine environment. The following subsections describe the environment from the point of view of the physicist, the chemist and the geologist. The interrelationship of these disciplines with the economic mineral potential of the oceans and seas is apparent from the description of the marine mineral resources. The marine environment is an extremely complex natural phenomenon with which the marine mining engineer must learn to live. It can be the source of his wealth or his frustrations and sometimes both. It can never be ignored.

Jan 1, 1973

By Robert Sturk, Knut O. Halvorsen

"INTRODUCTION AND BACKGROUND The world needs visionary people to break new ground and bring development forward. The human race has an inherent power and lust to explore and push borders, but also to connect and bring people together. Transport of people and goods has through history been a key factor to develop societies and increase collaboration between people and regions. Today, in the era of globalization, efficient transport systems are still vital for further development. Often, ideas of bold projects, like long bridges or tunnels, have been raised long before those projects are realized and actually built. This shows that visions must gradually be transformed into feasible business cases and sustainable political solutions. In some cases also technological development is necessary to make visions come true. Isambard Kingdom Brunel, indeed a visionary engineer, completed the oldest underwater tunnel in the world when the Thames Tunnel in London was opened in 1843. This tunnel is still in operation and now part of London’s rail transport system. Another milestone for the tunnelling industry was passed when the 54 km long Seikan tunnel in Japan was opened in 1988 after more than 15 years of construction. This tunnel is presently the world’s longest railway tunnel. Together with the 50.5 km long Channel tunnel between the UK and France, which has the longest undersea portion 37.9 km, they constitute examples of pioneering engineering projects that bring the industry forward. In 2016, the Gotthard Base Tunnel will be opened and then becomes the longest railway tunnel in the world with its 57.1 km. The trend is obvious that tunnels throughout the world are getting longer and longer. The Brenner Basis Tunnel presently under construction will yet again break the record being 64 km long. Presently, a number of even longer tunnels are planned and under design, some of these also have very long subsea portions, e.g. Bohai Straight Tunnel (123 km), Irish Sea Tunnel (around 100 km) and the Helsinki – Tallin fixed link (approximately 90 km). Northern Europe sees an increasing demand on efficient transport corridors to meet the growth of freight transportation between the Scandinavian Peninsula and central-Eastern Europe. Sustainable solutions will be required, and a shift from road/maritime transports to rail is imperative. Consequently, this paper describes yet another visionary project, a fixed railway link between Sweden and Germany, the Shortcut, to enhance traffic between these regions and to make it greener. It is true that this project still requires some work from politicians, economists and engineers to be realized, however, building a 100 km long tunnel under the Baltic Sea may become reality sooner than we think."

Jan 1, 2016

By Basilio Giurgola, Federico Bonaiuti, Norbert Fuegenschuh

The North East Boundary Tunnel (NEBT) project in Washington, D.C. requires design and construction of several SEM adits which have to be built between lateral shafts and the NEBT-TBM Tunnel. The paper describes ground improvements, the actual excavation, and also the final lining works. Schedule and sequencing restrictions provided some unique challenges which had to be considered when designing and constructing these mostly short, but essential portions of the project

Dec 1, 2022

By Ian Sherrell, Christian Cardoso, Henri Vepsäläinen, Guillermo Bermudez

Performance of mixing mechanisms in flotation cells is paramount, as inefficiencies can lead to financial losses through valuable minerals lost to tailings. Technological advancements have been implemented in flotation cells to optimize performance, but regardless of the efficacy of these developments, room for improvement may persist. Since its launch in 2005, FloatForce® has set a high industry standard for flotation mixing mechanisms. However, current mining trends call for sustainability-driven developments while improving metallurgical performance. Metso has recently introduced FloatForce®+, the latest iteration of FloatForce, developed through extensive laboratory, pilot, and industrial testing, aligning with mining sustainability trends. It has been designed to maximize recovery, reduce power draw and optimize manufacturing materials. This development stems from a redesigned rotor profile paired with a harmonizing stator configuration. This paper presents the development journey of Metso’s latest patented flotation mixing mechanism, an advancement to improve metallurgical performance at a high sustainable standard in flotation cells. The theory, CFD modeling and test work are discussed in detail.

Feb 1, 2025

By Zohreh Kazemi Motlagh, Evan J. Owen, Virginia T. McLemore, Jakob Newcomer

Five-element style deposits are unusual hydrothermal systems that are typically characterized by a nickel-cobalt-arsenic- silver-bismuth metal assemblage. This mineralization is often represented by abundant native silver, arsenic, or bismuth, and followed by nickel, cobalt, and iron arsenides (skutterudite, safflorite, nickeline, rammelsbergite, and lollingite). The Black Hawk district in Grant County, New Mexico is one of the few examples of this mineralization style in the United States. Despite the differences in formation temperature, depth of emplacement, and host rocks between five-element style deposits worldwide, there are commonalities in mineralogy, ore texture, and composition. A detailed exploration of the native metal and arsenide phases will be performed to compare ore forming fluids between systems and the effects on styles of mineralization and paragenesis, as well as to aid in broader classification of the deposit style. Mineralogy and mineral relationships of the Black Hawk District and other five-element deposits worldwide will be characterized by reflected light petrography, scanning electron microscopy, X-ray diffraction, and electron microprobe analysis. Mineralogical phase diagrams will be generated to better understand the driving processes and evolution of the systems through native metal and arsenide precipitation.

Feb 1, 2024