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By Roberto Dalmaso, Vinícius Pesente Binotte, Luiz Alberto Moreira Andrade, Alan Amorim Margon, Davi Fiorese Bissoli

Esse trabalho tem como objetivo apresentar o equipamento de medição automática de placas desenvolvido pela ArcelorMittal Tubarão na área de condicionamento de placas. Anteriormente este processo era realizado de forma manual pelos inspetores. Esse equipamento visa facilitar a rotina de trabalho do inspetor e aumentar a qualidade da medição, assim como diminuir a dispersão dos dados eliminando a divergência nas medições das placas que se verificava entre diferentes operadores, além de possibilitar a criação de um histórico das medidas de toda placa. Para validação do equipamento o mesmo foi submetido a um sistema de analise de medição e teve seu resultado aprovado, no momento atual o mesmo se encontra em funcionamento para se realizar uma comparação estatística do seu desempenho em relação aos inspetores..

Oct 1, 2019

By Kyoungkeun Yoo

A citric acid leaching test after heavy medium separation process was performed to remove the heavy metal contaminat such as Pb, Cu, and Zn from contaminated soil. The lead component was removed from soil by heavy medium separation whereas zinc component shows 0 % - 37.9 % removal ratio with particle size. The citric acid leaching was conducted to remove the remained zinc component. The removal ratio of Zn reached to more than 95 % under the conditions; 10 % in pulp density, 200 rpm in agitation speed, 50 °C, 2 mol/L in citric acid concentration at 2 hrs in leaching time. These results suggest that the heavy medium separation method followed by citric acid leaching is effective for treatment of soil contaminated with various chemical forms of heavy metal. Keywords: metal contaminated soil, citrate, heavy medium separation, zinc

Sep 1, 2012

By Mohamed Elgouhary, Carol L. Tasillo, Daniel Koziol

"The Bolivar Dam, located near the Village of Bolivar, Ohio is one of a system of dams designed to provide flood control and water conservation in the Muskingum Watershed. The Bolivar Dam is a “dry dam” that only impounds water during flood events. In order to address problematic seepage, which negatively affects the structural stability of the dam, the U.S. Army Corps of Engineers (USACE) designed a partial-depth and partial-length Seepage Barrier Wall (SBW) through the upstream slope of the dam. For this project, TREVIICOS constructed a 36 in (914 mm) positive SBW by plastic concrete panel wall method and excavated using hydromill and clamshell equipment. The plastic concrete was manufactured on-site, which allowed for enhanced quality control and prompt service. This required the installation, commissioning and operation of a concrete batch plant on-site. This paper presents the challenging aspects of the design, manufacture and placement of the plastic concrete for the SBW in order to meet contract strength and permeability requirements as well as workability requirements necessary for tremie concrete placement.Project General InformationBolivar Dam is located in Northeast Ohio (Fig. 1). It is one of a system of sixteen dam projects designed to provide flood control and water conservation in the Muskingum Basin, which covers 20 percent of the State of Ohio (Fig. 2). Bolivar Dam is on Sandy Creek, a tributary of the Tuscarawas River.The Dam has been constructed, operated and maintained by the USACE, for the Muskingum Watershed Conservancy District. Its construction was completed in 1937 and it has been in operation for flood control since 1939.Bolivar Dam is a rolled earth fill dam, with a typical embankment section made of a central impervious core flanked upstream and downstream by a pervious outer shell with downstream rock toe. The embankment has a maximum height of 87 ft (26.5 m) and a crest length of 6,300 ft (1,920 m), and is comprised of the main embankment starting on the left abutment of about 1,500 ft (457 m) heading to the Northeast, followed by the terrace embankment of 4,800 ft (1,463 m) heading to the North. An upstream impervious blanket extends up to 500 ft (152 m) upstream of the dam along the majority of its length. The outlet works are to the left of the embankment, and consist of an intake structure with six gates, followed by two outlet conduits that finish in a stilling basin. To the left of the outlet works is the uncontrolled emergency spillway, which was doubled in width to 540 ft (165 m) in 1989, and excavated material utilized for construction of a stability berm against the upstream face of the main embankment. A concrete parapet wall was also installed along the upstream side of the crest during this work. In 1982, a toe drain, downstream filter berm and line of 35 relief wells were installed. The filter berm was recently extended an additional 200 ft (61.0 m) downstream and granular filters were placed over an approximate 2000 linear ft (610 m) reach of the lower terrace slope. (Fig. 3)."

Jan 1, 2016

In 2005, a total of 4,490 stone mining operations reported employment to the Mine Safety and Health Administration (MSHA). Stone mines comprised 30.6% of all mining operations. ? Mines producing the primary commodity of limestone (crushed and broken) comprised the largest number of operations (n=2,039; 45.4%). ? Stone mining operations were located in all states and territories except Delaware and North Dakota. ? Of all states, Pennsylvania had the most stone mines (n=379; 8.4%).

Jan 1, 2008

By C. J. Toberman

Improvements in fine (28x0) and ultrafine (200x0) coal cleaning is an acknowledged goal with potential benefits in both steam and metallurgical coal markets. This work focuses on adaptation to fine coal flotation of FLOTE, a computer simulation model of the froth flotation process originally developed in the hard minerals field. FLOTE describes the flotation of solids based on particle surface activity, composition, and size. The quasi steady state model was applied to predict flotation performance at an Eastern Kentucky, full scale metallurgical coal preparation plant. Parameter estimation and model testing used detailed flotation test data from a five stage rougher flotation bank. Overall grade/recovery predictions compared well with known plant performance under variation of principally feed grade, plant throughput and reagent addition; however, grade/ recovery predictions for each cell weaken under overloading conditions. Analysis of grade/recovery over a range of sizes is presented. Suggested model improvements and extensions are discussed.

Jan 1, 1984

By Joseph W. Leonard

By combining statistical methods with specialized coal technology, novel and widely applicable procedures are developed which are useful for making important decisions based on coal seam structure. By analyzing such properties as ash in visual coal types of seam cross sections and by processing the ash data to 100 gram increments of coal ranging from the top to the bottom of the seam, intraseam comparisons between data populations of samples from a given seam and a reference seam can be made. Moreover, illustrations are presented for estimating the number of drill cores required to purchase a specified level of sampling accuracy together with procedures for determining the probability that different coal scan cross sections are not unlike and by inference are therefore comparable. Such comparisons can be valuable when making important, costly and long prevaling decisions involving coal exploration, mining, preparation and utilization.

Jan 1, 1969

By Kenneth R. Chadwick, Thomas J. Tuozzolo, Terence P. Holman

"Micropiles are often installed to retrofit existing foundations that experience distortion and to underpin structures prior to future construction. The Dublin Road Pump Station project is an example of retrofitting due to a basal failure during construction that compromised the bearing capacity of the soils. A completed pump station settled and had to be restored to its original position, and work could not proceed until a new support system for the partially completed wet well could be designed and installed. The project involved the construction of three below-grade structures for a new pump station in a growing area of Jackson Township, N.J. The general contractor constructed three pump station structures consisting of a pump chamber, wet well and an inlet chamber in early 2006.The geologic conditions beneath the project site (Figure 1) consisted of loose/soft to medium dense/stiff sand, silt and clay to a depth of 40 ft below ground surface, underlain by medium dense to dense glauconitic silty fi ne sand. When the general contractor was constructing the wet well, which involved an internally supported sheet pile excavation 32 ft below the ground surface and 28 ft below the static groundwater level, basal failure, boils and ground loss occurred. Driven piles were installed to support the wet well structure, but additional ground loss was observed within and outside the sheet pile excavation, followed by settlement of the adjacent pump chamber structure. Post-failure investigations were conducted by Mueser Rutledge Consulting Engineers, N.Y. (MRCE), a geotechnical and foundation engineering consultant. Their investigation concluded that the ground losses around the pump station structures had compromised the supportive capabilities of the natural subsoils.The owner engaged Moretrench, a geotechnical specialty contractor, to work with MRCE to develop a constructible solution to support the pump station structures in general and to restore the pump chamber to its original position. Knowing that ground loss had already occurred as a function of the initial basal heave and subsequent pile driving, the team selected micropiles as the preferred foundation element, primarily due to their flexibility in bypassing these disturbed zones and generating capacity as a function of grouting volume and pressure. Drilled piles were also recommended due to concerns about causing additional settlement of the pump chamber if driven piles were used."

Jan 1, 2008

By Jean Philippe Santos Gherardi de Alencar

O fenômeno de colagem é a formação de aglomerados de pelotas, denominados clusters, devido à sinterização do ferro gerado durante o processo de redução. O resultado disto é a elevação da perda de carga nos reatores de redução direta. Tal fenômeno vem sendo estudado por vários pesquisadores, pois as práticas operacionais dos reatores têm priorizado o uso de temperaturas de bustle gas (BG) cada vez maiores, o que potencializa o aparecimento dos clusters. Uma alternativa para controlar a colagem é por meio de utilização de agentes de coating (AC’s). Em relação às matérias primas utilizadas como AC´s, as questões que surgem agora são as seguintes: Como se comportam os AC’s em temperaturas muito elevadas de BG? Qual seria a maior temperatura possível de BG? A fim de começar a entender a melhor maneira de responder a estas questões foram realizados alguns testes de caráter exploratório e não convencionais para avaliar o comportamento de alguns materiais de coating a elevadas temperaturas de redução. Os resultados destes testes mostraram a possibilidade dos AC’s funcionarem a temperaturas maiores que a de inicio do amolecimento da carga e que, nestas temperaturas, a sua granulometria pode ser parâmetro determinante para seu desempenho. O aprimoramento dos ensaios de simulação do processo de redução em reatores de redução direta é fundamental para responder as questões que se apresentam em relação ao tema.

Aug 2, 2018

By J. J. Jonas, J. L. Uvira

Equipment was constructed which permitted the hot compression of 99.8 pct Armco iron and 2.8 pct Si steel at constant true strain rates of 0.05 to 1 per sec over the temperature range 600" to 1000°C. A maximum true strain of 1.9 could be attained, followed by immediate quenching or by isothermal annealing. True stress-true strain curves were obtained, and the steady-state flout stress, a, strain rate, i, and temperature, T, were found to fit the following expression: The constants A, a, n', and AH were determined for the two ,materials. The activation energies obtained for Arrnco iron and silicon steel are 66 and 80 kcal per mole, respectively, and approximate those for seu- diffusion and for creep. This indicates that hot compression is a diffusion-controlled thermally activated process. THE hot compression of iron and steel is usually carried out in the austenite temperature range,1"7 as this is the one of greatest interest with respect to industrial hot working. However, a disadvantage of testing in the austenite range is that the hot-worked structure is destroyed by the phase transformations taking place during cooling. The present study was therefore carried out in the ferritic temperature range, and the hot-worked substructures were preserved by rapid quenching after deformation. The substructural results will be described in a separate paper, and the present communication is restricted to the strain rate/stress/temperature relationship observed during hot working. The results of hot-compression testing are usually given in the form of true stress/true strain curves, with a different curve for each temperature/strain rate ~ornbination.',~,~ Sometimes simple algebraic equations are fitted to the curves, so that certain extrapolations or interpolations can be performed.1'2'5 These equations are, however, devoid of mechanistic interpretations. The present study was undertaken to show that hot compression can be described by an equation of the type used in creep studies. That is, it will be shown that the temperature dependence of the strain rate in hot working is well-represented by an Arrhenius term, with an activation energy similar to that for creep. Also it will be seen that the stress dependence of the strain rate is similar to that for creep EXPERIMENTAL METHOD AND MATERIALS The investigation was carried out with the following three ferrous materials: 1) Armco iron; 2) Armco iron with 0.26 pct Mn; 3) 2.8 pct Si steel. The first two materials were utilized for investigations performed in the temperature range 600" to 800°C; the last one was used for tests at temperatures from 600" to 1000°C. The materials were of commercial purity,* as shown in Table I. Cylinders of five different sizes were prepared by strain annealing. The resulting mean grain diameter was 3 mm in the 1-in. Armco iron and 2 mm in the other sizes and grades. Different ratios of diameter/height were used to enable the determination of the coefficient of friction. The specimen faces were provided with concentric grooves, which acted as lubricant holders during compression, as recommended by English and ~ackofen' and others.2'9 Powdered glass lubricants were applied to the samples before hot compression to decrease friction and barreling, following the practice of previous investigator~.~~~~~~~~ Different mixtures of glass powder were used for each temperature, after the determination of suitable compositions by experiment.'' Equipment for Hot Compression. Hot-compression tests were carried out on an adapted 150-ton vertical hydraulic extrusion press and also on a modified high-temperature creep machine. The modified extrusion press was used for temperatures up to 800°C. The following items were added to the press: a) a high-temperature furnace with built-in upper and lower platens; and b) a transmission assembly, which permitted the attainment of logarithmically decreasing crosshead speeds. These accessories are described in detail in Ref. 11.

Jan 1, 1969

By P. S. Haury

"INTRODUCTION Preliminary examinations of the Mohawk zinc prospect were made by John 14. Price and the author in July, August, and September 1943. Considerable quantities of oxidized lead and zinc minerals were found in old shallow work¬ings along two faults - one an over thrust fault with Paleozoic limestone in the hanging wall overlying Cretaceous shale and arkose in the footwall of the fault, and the other a bedding fault in the Paleozoic limestone.The chances appeared good for finding important lead-zinc sulfide ore bodies at 200 to 300 feet beneath the surface, so exploration in three steps by the Bureau was recommended:Surveying, mapping, and character sampling of the outcrops with topographic and geologic mapping of the immediately surrounding area.Preliminary drilling of four test holes, aggregating about 1,500 feet, to locate the top of a possible sulfide ore zone and determine the thickness and intensity of the sulfide mineralization.Contingent upon favorable results of the second step, diamond drilling of about 6,300 feet of additional hole to explore the sulfide ore bodies.The outcrops were surveyed and sampled, a topographic map was made of the area, and the geology was mapped. A project was set up for preliminary drilling of step 2 in the fiscal year 1944-45. An access road to the drill sites was built in April 1945. Diamond drilling was started on April 28 and completed on September 25, 1945, under the supervision or the Bureau of Mines. The exploratory work is covered in this report."

Oct 1, 1946

By N Donnellan

The Palaeoproterozoic Warramunga Formation is notable as the host to the enigmatic, so-called 'Tennant Creek style' mineralisation. These polymetallic (but mainly Au-Cu-Bi) ore deposits typically have a close spatial association with massive ironstone bodies, and frequently also with banded ironstone, known locally as 'haematite shale'. The Warramunga Formation is a polydeformed, turbiditic succession. Partial, or complete Bouma sequences variously comprising lithic arenite, wacke, siltstone, and mudstone constitute a classic flysch sequence deposited as a proximal (sandstone lithofacies) to distal (siltstone lithofacies) fan association. The Warramunga Formation has a substantial component of volcanic detritus and has generally been attributed to an essentially contemporaneous volcanic provenance. However, lithostratigraphic revision (Donnellan, Hussey and Morrison, in press) apparently precludes outcropping volcanic rocks of the Tennant Creek Block, or indeed Inlier, as the source of detritus. Warramunga Formation geochemistry indicates rapid derivation from a fractionated, predominately felsic igneous source (Palaeoproterozoic upper crust) with a minimum of chemical weathering; together with an admixture of mafic material. Warramunga Formation geochemistry cannot, however, be reconciled with that of the Bemborough Formation, which is here taken to be representative of Flynn Subgroup felsic volcanic rocks. Similarly, the Warramunga Formation is geochemically distinct from Flynn Subgroup sedimentary rocks. Geochemistry of the banded ironstone is consistent with its interpretation as Dine-grained turbidites.

Jan 1, 1994

By Arthur E. Morris

Fifty years ago when Professor Yazawa began his career, the field of process simulation and modeling was in its infancy. Since then, tremendous progress has been made in our ability to model metal production flowsheets from mine to refined metal. This progress has come about by parallel developments in basic understanding of process chemistry and in computational techniques, This paper will review the progress made in process understanding and modeling in lead, zinc, and copper metallurgy from its inception to the present, and the role of Professor Yazawa's work in furthering this progress. Specific examples will be given for the sintering of lead concentrates, slag fuming, zinc concentrate roasting, flash smelting of copper, and pyro-extraction of zinc. Factors limiting further progress will be described.

Jan 1, 2003

By Eduardo Luiz Sales Marinho

A Central Termelétrica SOL, ou CTEs 5 e 6, foi construída com o objetivo de fazer o aproveitamento da energia do gás oriundo do processo de coqueificação do carvão mineral realizado em fornos específicos para este fim, em um processo denominado “Coqueria Heat Recovery”. Nesta unidade operacional de responsabilidade da área de energia da ArcelorMittal Tubarão, seguindo o plano plurianual de manutenção nas turbinas Fuji, foi realizado intervenção de manutenção nos dois turbo gerados CTE’s 05 e 06 no ano de 2015. Durante as atividade de inspeção de manutenção foi detectado que existiam trincas nos pés das palhetas encaixadas no rotor da turbina nº6. A partir desta constatação, o equipamento ficou sem confiabilidade para operação continua, precisando de substituição das palhetas danificadas. O trabalho proposto apresenta as alternativas possíveis até a solução definitiva que foi a substituição das palhetas defeituosas por novos spare parts. As possibilidades descritas a seguir, serão o objeto de tomada de decisão até a normalização do equipamento: i) Montar TG e operar com palhetas do ultimo estágio trincadas até a chegada do sobressalentes para troca; ii) Deixar equipamento parado aguardando chegada dos sobressalentes para troca e conclusão da montagem e testes; iii) Remover por usinagem de campo, o ultimo estágio de palhetas do rotor montagem e operação do TG6 até a chegada do sobressalentes vindos da Fuji Japão.

Aug 17, 2017

By Barry J. Hansen

In the past six years, the Hanna Mining Company has increased its pellet producing capabilities greatly by the construction and expansion of six pelletizing plants in North America. At the present time Hanna managed pelletizers have a nominal capacity of 18 million long tons per year. This capability makes Hanna one of the world's largest pellet producers. To create and maintain such an operation has required the skill and dedication of many people in all aspects of the company's activities, in the various fields of exploration, operations and research. The Research and Development Group consists of the staffs of two laboratories situated on the Mesabi Range in northern Minnesota. These laboratories are well equipped to carry out work in the fields of beneficiation and extractive metallurgy especially iron ore treatment. Facilities exist for the batch and semi- continuous investigation of the unit operations common to iron ore beneficiation and pelletizing. The R and D Division is divided into groups according to specialized areas of interest. Presented in this paper today are some aspects of the activities of the Pelletizing Group of the Research & Development Organization.

Jan 1, 1969

By B. T. Lusk, Q. Q. Huang, R. Q. Honaker, K. A. Perry

Rock dust is applied in underground coal mines to prevent the propagation of coal dust explosions. It is applied either dry or wet. Both methods have advantages and disadvantages, but the formation of caked rock dust particles is cited as a significant concern for wet applications. We conducted a study to evaluate the effect of modifying the rock dust particle surfaces to repel water and each other by the addition of oleic acid and sodium oleate. At a sodium oleate dosage of 1 kg/t, a contact angle of 112o was measured, indicating strong surface hydrophobicity and thus the ability to repel water. Fourier transform infrared spectroscopy (FTIR) studies indicated a chemisorption mechanism, which is necessary for long-term stability of the surface modification. The dispersibility of the modified rock dust samples was elevated by the application of both oleic acid and sodium oleate, thereby indicating a significant reduction or elimination of the detrimental effect of caking. Tests in an explosion chamber showed an 82.8 percent reduction in the dust explosion potential relative to untreated rock test applied by the wet technique.

Jan 1, 2015

By Guilherme Bougleux Michelin Assunção

O projeto visa o estudo da reatividade e da resistência do coque, combustível tradicionalmente utilizado na siderurgia, relacionando às diversas condições presentes no alto-forno. Para a realização da pesquisa, foram utilizadas amostras de coque de uma empresa siderúrgica nacional. O coque foi analisado através dos ensaios Coke Reactivity Index (CRI) e Coke Strength After Reaction (CSR) no Laboratório de Processos Metalúrgicos da Universidade Federal de Minas Gerais (UFMG). Os testes foram realizados em tempos e temperaturas pré-determinados para simular as diversas zonas percorridas durante a descida do termo-redutor nos altos-fornos. Os resultados mostraram a viabilidade termodinâmica da gaseificação do coque a partir de 900°C, sendo possível calcular a energia de ativação da reação de Boudouard a 1100°C, e a correlação entre CRI e CSR coque.

Aug 17, 2017

By Hector O. Romero, Paulo C. Fernández A, Christian Rees Prado, Claudio C. Gajardo

In open-pit mining, estimating post blasting displacement and spillage accurately is essential to guarantee operational efficiency, ensure alignment with production plans and their associated key performance indicators. The absence of predictive modeling tools on blasting operations results in several critical challenges, including operational reworks due to deviations in material displacement, significant discrepancies between mine and plant (ore grade dilution included), misalignment with the reported production plan, and increased operational costs due to inefficient use of resources. This study, conducted at Los Bronces Mine operated by Angloamerican, Chile, addresses the application of a three-dimensional simulation tool that, through numerical modeling, is capable of predicting post blast rock displacement. The implementation was carried out in a pit phase characterized by blasts near the pit boundaries, with a high risk of material spillage and potential blockage of the only access ramp to the extraction levels. By the integration of key design parameters, such as blast pattern geometry, detonating time, explosive charge distribution and pre and post blast survey, an optimal calibration was achieved and validated in seven blasting events to date, reaching an accuracy greater than 80% in estimating post-blast rock displacement and spillage volumes. Furthermore, this study allowed the evaluation of different pattern alternatives with and without spillage mitigation measures (use of air decks near the free face), obtaining a high correlation and accuracy exceeding 95% in predicting the selected design outcome, supporting optimal design selections. The result highlights the usefulness of the model as a decision-support tool for blasting engineers and short-term planning, by reducing the need for unnecessary operational reworks, improving geological and operational reconciliation, and ensuring the alignment of the extracting plan with production targets. The current average deviation is 15%, with higher deviations observed in blasts with smaller volumes of spill or where the simulated sequence was changed before blasting. The use of this type of three-dimensional numerical modeling represents a significant advancement for blast engineering and the optimization of key performance indicators in open-pit mining operations.

Jan 26, 2026

By José Eustáquio da Silva

Este trabalho mostra a versatilidade e praticidade do uso da metodologia denominada “Método e Aparelho para Avaliar as Propriedades de Coqueificação do Carvão”, metodologia esta desenvolvida e patenteada pelo corpo técnico da SunCoke Energy. Esta técnica tem possibilitado o desenvolvimento de novas misturas de carvões totalmente alinhadas com os dois grandes pilares da Siderurgia mundial: misturas e coque com baixo custo e qualidade adequada. A fidelização com todas as particularidades do processo real de coqueificação faz desta metodologia uma poderosa ferramenta para tomada de decisão na definição de novos blends, como também para a caracterização de carvões dos quais ainda não se conhece seu potencial para produzir um coque de boa qualidade. Diferentemente das tecnologias similares existentes, o “Box Test” da SunCoke Energy tem robustez suficiente para ser reutilizado para até quatro enfornamentos e é capaz de produzir massa suficiente de coque para que sejam realizadas todas as análises para uma perfeita caracterização do coque.

Aug 17, 2017

By Rodolfo Dal Alva Pinto

Uma linha contínua não só melhora o conforto aos usuários, mas também melhora as condições de desgaste, fadiga e manutenção dos equipamentos ferroviários. Porém os parâmetros de soldagem devem ser bem especificados e controlados de forma a obter uma junta soldada adequada. Neste trabalho foi desenvolvida a avaliação do desempenho da soldagem aluminotérmicas de trilhos. Os resultados obtidos foram empregados em ações de melhoria da qualidade da soldagem aluminotérmica, conforme relatado em outro trabalho apresentado neste evento.

Aug 16, 2017

By Frederick T. Williams

THE purpose of this paper is to discuss the relative merits of the large 31/8 in. machine and the small 21/4-in. tappett machine in driving development-headings ; and although the . data here presented were obtained from cross-cut headings alone, experience has shown that the results are equally true in drifting, raising and winning. Recently we drove two parallel cross-cuts through the same formation, using a 3k-in. machine at the breast of one cross-cut., and a 2k-in. machine of the same make at the breast of the other. The results of this work afforded an ideal comparison, since in both cases the headings were advanced through rock practically of the same hardness and breaking-properties ; the amount of sludging was equal, and there was no difference in the condition of the steel or the machines, in the air-pressure or in the experience of the operating-crews. Some operators in the Cripple Creek district contend that there is ground which cannot be handled with the small machine, the holes being too small to contain enough powder to pull the ground, etc. The results obtained in working the property of the Portland Gold Mining Co., however, show that the ground worked by them does not fall in this class. During a period of two years there have been driven, with the small machine, 4 miles and 308 ft. of development-headings, through a diversity of ground, including Pike's Peak granite (a coarsely porphyritic type of granite), highly indurated, andesitic or phonolytic breccia, true massive andesite, trachytic phonolyte, tuffas, and along dikes of decomposed basalt and hard phonolyte; in every instance a satisfactory record was made. The headings here described were driven through highly indurated, andesitic breccia, having a hardness of from 5.2 to 7.2

Mar 1, 1906