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By John A. Teeter

"A SHORT WHILE AGO I enquired about The Mining Society of Nova Scotia. In all honesty I was apprehensive about addressing such a body if it was highly geared to the technical aspects of discovering and obtaining mineral resources. I was told that this would not be the case. Rather, there would likely be in attendance a broad cross section of people from business, industry and government and from across Canada and the U.S.A. Thus there would be an interest in a free-wheeling discussion of the prospects for industrial development in Cape Breton. Accordingly - being one who hates to miss an opportunity - I intend to exploit the invitation of your executive by being, over the next short while, frankly promotional. I would like to talk about what I consider to be some of the most important attributes of Cape Breton for industrial development and identify some of those prospects. Secondly, I will quickly review some of the things the Cape Breton Development Corporation is doing these days to stimulate some of that industrial development."

Jan 1, 1972

By Marino Carrión P

Ante la crisis ecónomica que afecta al sector minero, este ha previsto expandir su producción y reducir los costos operativos que le competen. En esta perspectiva, la Compañía minera Atacocha busca ampliar su rango de producción a partir de la elaboración de un proyecto racional del ore-body Santa Bárbara. El proyecto consiste en explotar el cuerpo mineralizado por encima del nivel 400. Sin embargo, las condiciones para la mineralización son insuficientes. En este sentido, el presente texto presenta una alternativa de explotación mecanizada donde el cuerpo mineralizado tolere los niveles altos de temperatura a través de un nuevo block que se aplique en la profundización del ore-body y puede minimizar los costos operativos que esto conlleva.

Apr 1, 1991

By Christopher J. Brown

"Proper ground stability in gate roads has been a critical aspect of success in longwall mining. In particular, the tailgate has proven to be one of the more active mine areas that needs to be managed (Barczak, Dolinar, and Mucho, 1999). As longwall tailgate support technologies continue to be developed and improved, Strata Worldwide has worked to design and manufacture a revised Propsetter to provide additional support capacity and enable applications at greater mine heights. The support is targeted for tailgate applications; however, it can also be used for roof support in various types of mining environments. This paper describes the design changes for enhancing the support capacity of the Propsetter to more closely align its performance with other support technologies currently being employed in longwall tailgates. Balancing changes to each design aspect of the Propsetter was key to successfully improving the roof support load capacity while maintaining controlled deformation. Increasing the load capacity would allow a mine to improve support efficiency with a smaller, less intrusive support compared to support alternatives and to reduce the cost per foot of supported entry. The target support capacity was 80 to 100 tons at two inches of deformation to more closely match the performance of competing tailgate supports, such as the 24-inch-diameter CAN®. To achieve this goal, changes were made to all design aspects of the Propsetter: diameter, wedge cut depth and angle, pod size, and confinement rings. Test results from the NIOSH Mine Roof Simulator verified that these design changes were successful in increasing the capacity of the Propsetter to the 80- to 100-ton range at two inches of deformation. INTRODUCTION Roof support is one of the most fundamental elements of the underground mining process. As materials are removed from the earth, geological conditions will almost always require some form of roof support to keep the extraction area open and stable. Coal mining environments often experience difficult geological conditions that require both primary and secondary forms of roof support to keep the mining environment safe and economical. The secondary support system serves as additional support in the case the primary support system is inadequate. If designed properly, the secondary support system will also assist in maintaining integrity of the immediate roof beam (Barczak, 2000)."

Jan 1, 2017

By S-C Shim, H-R Lee, Y Kang, H Shin

Since iron oxide and silicon oxide are major gangue components in various types of ore, FeO-SiO2 base slag, ie fayalite slag, has been often encountered in pyrometallurgical processes of non-ferrous metals. During most matte production processes such as the smelting of Cu, Pb, and Ni, the FeOSiO2 based slag is inevitably formed and plays an important role in refining crude metal as well as engineering aspects. Recently, similar pyrometallurgical approaches have been attempted in the recovery of valuable metals (Ni, Co, Cr) from wasted secondary batteries. Thus, the viscosity of the FeO-SiO2 based slag has great significance in properly controlling smelting processes. However, when molten metal or matte does not coexist with the slag during the measurement, there has been a serious difficulty in maintaining Fe valance and consequently, the slag composition. In the present research, the viscosity of molten FeO-SiO2 slag was measured in 1573~1673 K using a rotational viscometer. In order to keep the state of iron oxides, the oxygen partial pressure was controlled using CO/CO2 gas mixture. The optimised ratio of CO/CO2 could be calculated using Fe/Fe2+ and Fe2+/Fe3+ equilibria at each temperature. The composition of the slag, particularly Fe valance, after the measurement was analysed with the aid of an inductively coupled plasma – optical emission spectroscopy (ICP-OES) and an automatic potentiometric titrator. The measurement showed that the FeO-SiO2 slag has considerably low viscosity values in the molten state, and it sharply increases as the temperature decreases. In spite of the careful oxygen partial pressure control, a part of Fe2+ was found to be oxidised to Fe3+, with a maximal case reaching about 20 per cent. The increase in viscosity of FeO-SiO2 at low temperatures can be attributed to the composition change due to an unavoidable Fe2+ oxidation. In addition, the relationship between the change in the viscosity and the liquidus temperature of FeO-SiO2 based slag was discussed to understand the composition dependence of viscosity.

Jun 19, 2024

By E. P. Youngman

From a scientific point of view , the zircon is by far the most remarkable of the gem stones , and a satisfactory solution of the problems offered by its characters and constitution has not yet been made . 3 Three distinct forms have been recognized , differing in specific gravity , hardness , optical properties , behavior when heated , and color.4 ( See section of this paper entitled "Description and Properties . " ) Zircon as a gem stone has not been as well known as its properties warrant . It is one of the most brilliant of the precious stones (having a high refractive index) . The colorless zircon rivals the diamond in brilliance and fire play to such an extent that a judgment based entirely upon optical inspection might be erroneous . In the opinion of gem authorities , the colored stones likewise have much merit . The blue zircon ( " Starlite" ) was so named by Kunz because of its resemblance to a " star twinkling in the night . " Another gem authority describes the leaf- green stone as one possessing a restful beauty , the red stone as having a certain ( though somber) grandeur , and the golden-yellow stone as being unsurpassed in magnificence . The slowness with which the zircon , a stone frequently mentioned in ancient literature , has come into use in modern jewelery may be owing to the fact that authorities differ as to whether the colorless and the blue zircons are found as such in nature or are treated stones . Any treated stone , although the material of which it is composed may be essentially genuine , has been considered a deception . However , according to Kunz , " Starlite is now sold over the entire world ; never has anything been so well introduced. "7 Dr. Foshag, mineral curator of the United States National Museum, states that the first allotment of zircons to enter the United States was obtained in 1921 from Siam ( through France ) for scientific or museum purposes and that four or five years later the stones were adopted by the jewelers of this country . Retail jewelers are displaying the colorless type and the blue stones , especially , in finger rings , necklaces , and like ornaments . Fine crystals have been used somewhat extensively in jewelling watches and as supports for the edges of fine balances . At one time zircons were though to be appropriate in mourning jewelery .

Jul 1, 1931

By G. B. Botsford

In August 1943 the Bureau of Mines began an investigation of the West Portal magnetite mines, which comprise the Swayze and Turkey Hill properties. The work included (1) traversing with a dip needle to record magnetic anomalies, (2) diamond drilling, and (3) sampling old mine dumps; it was completed in April 1944. The deposit consists of two parallel veins, which strike northeast and dip southeast. They carry magnetite in gneiss and schist. The Swayze mine was discovered in 1867 and closed in 1889, while the Turkey Hill mine was opened in 1872 and closed in 1887. The dip-needle survey covered 266 acres. The diamond drilling comprised 11 holes totaling 4,910 feet from which 142 samples were taken for chemical analyses. Old mine dumps were sampled at 52 points for chemical and magnetic analyses.

Jan 1, 1948

By I. AITKENS

The opal , long in disfavor because it was considered " unlucky, " has become much more popular in recent years . For variety and beauty of color the precious opal is without a peer . These colors do not come from any chemical constituent but are produced by structural peculiarities , which in varying degrees deflect the light rays entering the stone and give a prismatic play of hues .

Sep 1, 1931

By S. R. Noble, F. R. Harris, E. T. C. Spooner

"The Logtung deposit discovered in 1976, is an example of large tonnage (162 million tonnes), low grade (0.13% WO3 and 0.052% MoS;) W(scheelite)-Mo mineralization related to multiple felsic intrusions. Because mineralization is predominantly fracture-controlled (> 95 %) rather than disseminated, Log tung is not a skarn deposit. Metamorphism of the Logtung country rocks (interbedded calcareous shale and graphitic quartizite) to a series of competent reaction skarns (quartz-diopside-garnet calc-silicate, biotite quartzite and wollastonite-vesuvianite calc-silicate) clearly precedes W-Mo mineralization. Hence mineralization was related to permeability created by hydraulic fracturing and not replacement processes.Logtung shows a theme of several phases of mineralization (4) related to multiple intrusions (>2) which is similar to that of the Climax and Urad-Henderson Mo systems. The earliest quartzmolybdoscheelite vein system, which consists of a typical ""porphyrystyle"" crackle-breccia of thin (0.5 mm to 4 mm) quartz-garnetdiopside- molybdoscheelite veins, is related to a high Si02 (approx. 76%), seriate-porphyritic monzogranite stock (approx. 2 km by 0.5 to 1 km) of Cretaceous age (118 ±2 Ma [2u]; Stewart, 1983). Later quartz-pyrite scheelite (fluorite-KINa-feldspars-molybdenite) veins, with prominent green, hornblende-bearing alteration selvages, and quartz-molybdenite (-pyrite-jluorite-scheelite) veins are related to a quartz-feldspar-spessartine-rich garnet porphyritic felsic dike complex approximately 500 m across. Both intrusive phases have anomalously high Wand Mo concentrations of about 100 ppm and 50 ppm respectively, which Stewart (1983) attributes to a primary enrichment. The final stage of mineralization consists of a prominent 4.5 km by 1 km zone of 1 em to 1 m wide polymetallic sheeted veins centred on the felsic dike complex. The system is zoned from quartz scheelite-molybdenite-pyrite-blue-green beryl-jluoritebismuthinite veins in the core to Pb-Zn-Ag veins with abundant arsenopyrite and minor Sn (approx. 0.1%) in the northeast. The focus of recurrent intrusive and hydrothermal activity was located above a flank or nose of the monzogranite stock.The distribution of WO3 and MoS2 grades within the approximately 750 m (across) by 300m (evaluation depth) mineralized zone is a result of the variable superimposition of the four separate vein systems each with different W:Mo ratios. Well-defined Wand Mo ore, shells such as those at Climax, Henderson and Mt. Emmons did not develop at Logtung. The upper surface of the mineralized zone, as shown by the 0.03% MoS2 contour defines an elongate dome with an apical region approximately coincident with the felsic dike complex. Hydrothermal alteration occurs as well-defined vein selvages, and not as pervasive zones.The Logtung deposit shows many similarities to porphyry Mo deposits in the western Cordillera and may be identified as a porphyry W(scheelite)-Mo deposit, with a W:·Mo ratio of 3.3:1. The principal reasons are: (1) mineralization is spatially associated with porphyritic granitic intrusions and (2) much of the scheelite and molybdenite occurs in typical ""porphyry-style"" vein stockworks"

Jan 1, 1995

By T. J. Ballard, Austin B. Clayton

"The Union Copper mine is in the Gold Hill district, Rowan and Cabarrus Counties, N. C.The mine was discovered in 1799 and first worked as a gold mine; but copper was encountered at depth, and the property became an important producer of copper. It is estimated that the mine produced 5,000,000 pounds of copper before operations were discontinued in 1907.As part of the strategic minerals program, the Bureau of Mines conducted a development project on the property from July 1943 to November 1943. Eight diamond-drill holes, totaling 2,500 linear feet, were drilled to delineate the ore body. Analyses of 205 core samples were made.Tabulations of sample analyses and drill-hole logs are presented in this report.The project work embodied in this report was under the immediate supervision of Austin B. Clayton, project engineer, and the general supervision of H. B. Ewoldt, district engineer for North Carolina and Tennessee. The preliminary report, written by Austin B. Clayton, was revised and the various figures redrawn for publication by T. J. Ballard under the general supervision of M. H. Kline, chief, Raleigh Branch, Mining Division.Acknowledgment is due the Metallurgical Branch for analytical determinations of the samples.The mine property is 1.5 miles southwest of the village of Gold. Hill, N. C. (fig. 1). Gold Hill is on U. S. Highway 52 between Salisbury and Albemarle and on a branch line of the Southern Railway. The latitude is 350 30' and longitude 80° 21 The tract consists of 553-1/2 acres in Cabarrus and Rowan Counties.A tentative list of the surface-rights ownership is as follows: William Hoy Barringer - 16 acres, A. W. Tucker - 1 acre, Frank Wagoner - 4 acres, and George Barringer - 3-1/2 acres, in Cabarrus County; A. W. Tucker - 2 acres, H. N. Hedrick - 54 acres, and William Atkins - 473 acres, in, Rowan County, N. C.The mineral rights are owned by Alfred Rossiter, Alice R. Hesslein? and the estate of the late Bella Rosenblatt. The attorneys for the owners are Neidle & Taylor, 6 East 45th Street, New York City.The Union Copper mine is in the Cold Hill mining district of North Carolina where gold was first discovered in 1799. The upper parts of the veins in the district were first worked for gold; however, the increase in the sulfide content of the veins with depth rendered the amalgamation process for gold recovery ineffective, and the mines were closed.The period of greatest activity at the Union Copper mine was from 1899 to 1906. At an earlier period the oxidized and leached part of the lode near the surface was mined from a working known as the ""big cut,"" the reported yield of which was $300,000 in gold.3/ The mine has not been operated since 1907.J. T. Pardee3/ lists the probable value of the production of the Union Copper mine as $1,050,000, of which about $675,000 was the value of some 5,000,000 pounds of copper produced."

Oct 1, 1948

By A. Daouadji, P. Cazes, S. Grange, L. Briançon, R. Milane

Construction in congested urban areas is often accompanied by geotechnical problems due to high loads and the impact caused by nearby buildings. For this reason, it is important to understand the behavior of the soil and the structure without forgetting the essential role of the interaction between them. Experiments, instrumentation and numerical modeling are the main methods used to study this behavior. To this end, pressure cell, strain gages, vibrating wire extensometers and optical fiber sensors are installed on the reinforcement steel of pile and raft foundations to monitor stresses and induced deformation in these elements during and after construction. A fiberglass rod extensometer is placed in the soil to help measuring the displacement due to excess loading, knowing that the pile foundations are embedded in the Rhône’s alluviums and reach the molasse, a particular and challenging soil with properties that are not yet well understood. The objective of this paper is to present the geotechnical instrumentation program carried out for the tower Silex2 in Lyon, France, and to describe the types of sensors used and their installation on site. INTRODUCTION The complexity of geotechnical structures like dams, bridges or high-rise buildings requires a sound understanding of the behavior of the soil, the structure itself and the interface. Therefore, a geotechnical instrumentation program can be essential in many ways. During the site investigation stage, it can help determine the initial conditions experienced by the soil in the field by measuring parameters such as the compressibility index or the permeability. During the construction stage, real time measurements can protect the structure from premature failure, help validate and optimize the design if needed. In addition, sensors measuring pore-water pressure, loads, deformations and settlements allow for monitoring the performance of the structure. This is called the observational method. Finally, during the operating phase, instrumentation aims to study the long-term behavior of the structure (Nicholson et al., 1999).

Jan 1, 2019

By W. W. Culter

"This paper is the outcome of thorough investigation into the value of the previous methods used for deriving production decline curves. It is highly important that methods be employed that are fundamentally sound and also practicably applicable. Six methods commonly used were studied. Some of these were found to be fundamentally in error; some save reliable curves but involved much work and time in the preparation; others gave reliable curves with less time and effort.It was found that of the methods previously employed the ""family curve"" method described in Bull. 134 Amer. Inst. Feb. 1918, pp. 499-500 by Lewis and Beal, was probably the most satisfactory. The now method given in this paper ploys the same principles as the ""family curve"" method, but is mathematical instead of graphical,The engineer and the oil man should carefully boar in mind both the use and the limitations of the average production curve such as is derived by the ""family curve"" method or other methods mentioned. Estimations of future productions or of underground oil reserves of a particular tract or well should be made from the production records of the tract or the well itself wherever such records are satisfactory. The use of the average curve of a district or field should be applied only to those properties or wells where there are not sufficient data to construct individual or tract production records, or where the productive life so short that a satisfactory individual record can not be obtained."

Jul 1, 1920

By Otávio da Fonseca Martins Gomes, Renata Hiraga de Vasconcellos Cruz

Maghemite is a mineral formed from magnetite oxidation at low temperatures, an intermediate term of the magnetite-hematite series. Maghemite could be misidentified as magnetite by X-ray diffraction, and/or as hematite by spot chemical analysis. Nevertheless, non-stoichiometric magnetite was detected and quantified in samples of Brazilian soils and iron ores by the Rietveld method refinement of its structure. The results were confirmed by optical microscopy and Raman spectroscopy, thus validating the method. X-ray diffraction with the refinement of the isomorphic substitution of Fe2+ by Fe3+ along the magnetite-maghemite solid solution could help to suitably characterize maghemite in iron ores.

Oct 3, 2019

By Ruiling DU, Xiao YUAN, Keng Wu, Daan XU, Changyao CHAO

To utilize low grade coals to produce high quality semi-coke which can be used in blast furnaces, the pyrolysis of low grade coals was studied in this paper. According to the characteristics of coal pyrolysis process, the temperature range was divided into three parts. The interfacial chemical reaction model, random pore model and the internal diffusion model with the shrinking volume of resultant were established to describe the different ranges of pyrolysis process respectively. The results showed that the experimental data was fitted well, and all the correlation coefficients (r2) exceeded 0.97. Finally, the kinetic parameters for each temperature range have been calculated, which laid a necessary foundation for the simulation and expanded production.

Jan 1, 2016

By John P. Anderle

A tectonically disturbed sequence of Mississippian age evaporites expressing a 5 milligal negative gravity anomaly near Sussex in southeastern New Brunswick, Canada, was investigated by a program of drilling, geologic and geophysical work over the past 27 months. Seventeen of twenty-one drill holes have penetrated 10 to 140 feet of potash mineralization in a salt sequence underlying 2 000 to 3 000 feet of arenaceous, conformable red beds, also of Mississippian age. Bromine and borate studies, lithological characteristics and geophysics, have facilitated improved understanding of the salt structure. The salt sequence has been affected by f1owage which has resulted in both major and minor folding. In the more disturbed areas, the potash interval was extensively subterraneally eroded at the upper anhydrite-salt contact.

Jan 1, 1978

By William Gleason

During the 116th National Western Mining Conference and Exhibition in Denver, CO, the host city was often referred to as world?s mining capital, so it was fitting that the conference looked at the mining industry through a global lens. In the current world economy, the mining industry must keep a sharp focus on such things as commodity prices and global supply and demand as well as local issues that can have a dramatic impact on a mine?s social license to operate. In short, companies should mine locally but think globally. During the three-day conference at the Colorado Convention Center, a range of global and local issues that effect the industry were discussed. A record 1,144 people attended the conference.

Separation of Iron Particles from Banded Haematite Quartzite (BHQ) Ore by Selective Magnetic Coating The separation of fine iron particles from banded hematite quartzite (BHQ) has been studied using selective magnetic coating. The BHQ ore assays as 38.9 per cent Fe, 42.5 per cent SiO2 and 1.0 per cent Al2O3. Mineralogically, the ore contains hematite and quartz as the major mineral phases where as goethite and magnetite is present in minor entities. Natural magnetite of very fine size and oleate-magnetite in colloidal form, prepared synthetically in the laboratory are used as the coating material on the surface of hematite particles. The selective coatings of oleate-magnetite on BHQ surfaces followed by magnetic separation studies have indicated that, it is possible to achieve 62.3 per cent Fe with 8.5 per cent SiO2 at 85.4 per cent iron recovery. The recovery of iron values is found to be superior in comparison to the conventional magnetic separation techniques. The selectivity of coating for enhancing the magnetic response of iron particles is achieved by controlling the surface properties of the particle via electrokinetic potential adjustment by controling pH and addition of oleate-magnetite. In the separation process, the effects of pH, magnetic intensity and addition of oleate-magnetite are studied to achieve the maximum grade and recovery of iron values. The optimum separation is observed at pH of 7.5, oleate-magnetite concentration of 0.25 ml/g of BHQ ore and a magnetic intensity of around 0.8 Tesla. The X-ray diffraction (XRD), Infra-red spectroscopy (IR) and UV-visible spectroscopic studies strongly suggest preferential coating of magnetite on hematite surfaces. Scanning electron microscopy (SEM) studies have brought out the semi-quantitative features of BHQ ore. The recovery of iron values from a lean grade ore such as BHQ is carried out looking into the future needs of this ore in India for iron and steel making.

Sep 13, 2010

By Jorge Spangenberg, Lisard Torró, Patrick Quispe, al et, Johan Ramírez

Presentamos nuevos datos de isótopos estables de carbono y oxígeno que ayudan a delimitar el origen y la evolución de los fluidos del estadio C en el depósito de Zn-Pb-Ag-In-Sn-Cu de tipo cordillerano de Ayawilca. Los datos isotópicos de rodocrosita hidrotermal indican que los fluidos mineralizantes presentaron valores promedio de 13C y 18O de -13 ‰ (VPDB) y 19 ‰ (VSMOW), respectivamente.

May 10, 2023

By J. J. Moore

Combustion synthesis or self propagating high temperature synthesis (SHS) reaction systems are discussed with respect to thermodynamics and kinetics. In particular, tile effect of the process parameters, ego particle size, AHf, ignition and combustion temperatures on these self sustaining reactions is discussed. Combustion theory is used to investigate the effect of the overall activation energy of the SHS reaction on the combustion front propagation rate and in obtaining a clearer understanding of the transition from stable to unstable propagation. Finally, examples of the application of combustion synthesis to advanced materials processes are made, in particular the synthesis of Ni-Ti -X intermetallic shape memory alloys, TiC-Al2O3 and ZrB2 ?Al2O3 ceramic composite materials.

Jan 1, 1991

By S Jahanshahi

In an earlier LCA study, the authors showed that the electricity consumption of the electric furnaces used in the production of the ferronickel and ferrochrome feedstocks made significant contributions towards the Gross Energy Requirement (GER) of stainless steel production, on a æcradle-to-gateÆ basis. Given the relatively low efficiencies associated with electrical power generation, substantial reductions in the GER for stainless steel production could be anticipated if more direct use of thermal energy was made in the ferronickel and ferrochromium smelting stages.In view of these findings, a follow-up study was undertaken to investigate the likely environmental benefits of using bath smelting processes for the production of ferronickel and ferrochromium compared to the traditional rotary kiln-electric furnace processes, but still utilising the electric furnace process for stainless steel production. The METSIM process simulation software package was used to set up models of the two bath smelting processes and provide process energy requirements that were incorporated into the LCA. The environmental impacts considered in the LCA were greenhouse (Global Warming Potential, GWP) and acid rain gas (Acidification Potential, AP) emissions and solid waste emissions.The results of the study showed that the bath smelting route reduced the GER for ferronickel production by about 37 per cent over the traditional route, which translated to about a 21 per cent reduction in the GER for stainless steel. The corresponding reduction for ferrochromium was about half that for ferronickel, and when combined with the ferronickel result gave a 25 per cent reduction in the GER for stainless steel production. Similar reductions were also observed for the GWP and to a lesser extent the AP for both feedstocks, as all primary energy inputs were essentially fossil fuel based. Substantial reductions in solid waste emissions were also indicated for the direct use of ores in smelting. By utilising bath smelting processes for the production of the ferronickel and ferrochromium feedstocks, stainless steelÆs suitability for meeting many of the goals necessary for sustainable development, already recognised because of its particular properties, would be even further enhanced.

Jan 1, 2004

By Enrique Solari

"El presente texto describe el trabajo de las minas de plata, oro y cobre durante la Pre-historia en Chile. En Hauntajaya y Yabricoya los indios trabajaron el cloruro de plata o plata córnea y la plata nativa. Sin embargo, los atacameños y diaguitas, fueron los únicos habitantes prehistóricos que practicaron la metalurgia, aunque no utilizaron el fierro en ninguna de sus formas, debido a su alto punto de fusión. Asimismo, en los primeros cateos o prospecciones que realizaron los indios, buscaban rocas y minerales, tales como la arcilla, el cuarzo, la cuarcita, el sílex, el lapislázuli, la obsidiana, la calcedonia, el jaspe, el ágata, el pedernal y los trabajaron con un gran conocimiento empírico de clivaje para la confección de herramientas y adorno. El método usado en la prospección de minerales fue a través del color, cobre, verde siticatado llamado por los indígenas 'Tanca"" y el carbonato de cobre (malaquita- azurita) llamado por los españoles como ""cardenillo"". Asimismo, los cateadores de minas prehistóricas contribuyeron en el norte de Chile, -en tanto bagaje de conocimientos- de los cuales, los cateadores hasta la época de la República, se sirvieron a la gran aventura de los derroteros de minas. "

Mar 1, 1967