Distribution of Arsenic in Fresh and Weathered Rocks in Sri Lanka

This study was carried out to determine the distribution of arsenic, which may slowly harm human health, in the weathered rocks of different parent rocks in the country. 293 samples were collected from different crystalline rocks and in-situ weathered formations above the particular parent rock in 50 localities. Selected minor elements (including arsenic) were analysed by X-ray fluorescence spectrometry on RIGAKU KG-X system (Japan). Results indicated that the maximum arsenic amount in the fresh rock was 12 and 48 ppm in completely weathered rocks. About 86.9% of fresh rocks showed less than 5 ppm of arsenic, while 89.8% of their weathered grades showed the arsenic concentration to be less than 10 ppm. Average arsenic in all fresh rock samples was 3.5ppm (lowest); it was 7.6 ppm (highest) in residual soils. This is the normal condition of arsenic distribution worldwide. Under this condition, the arsenic concentration in natural groundwater in the residual soil areas should be below the acceptable limit. Therefore, the amount of arsenic released from parent rocks and their weathered products due to natural geological processes is very low in Sri Lanka.

Characterization of the unconfined compressive strength test in rocks by fine granulometry

This work presents a proposal for the characterization of the UnconfinedCompressive Strength test (UCS), through a series of operations that can be carried outwithout inconvenience in the field. Initially, fresh rock samples are obtained from outcropsin the area and specimens of specific dimensions are made. After the test specimenelaboration phase, crushing and granulometric classification tests are carried out witha set of specimens and in parallel with a second group, UCS tests are carried out. With theresults, the rock is characterized by graphing granulometric curves and in this graph theareas of fine granulometry are focused, inserting in these areas, the average value of UCS,with which it can be identified and determined when it is really necessary and It is inevitableto send rock samples to laboratories, thus saving time and money for the mining project. Keywords: compression, crushing, granulometry, rock. References [1] F. Blyth and M. de Freitas. Geología para Ingenieros. México: CEGSA, 2003. [2] F. Escolano and A. Mazariegos de la Serna. Guía de reconocimiento de rocas en Ingeniería Civil. España: Editorial Garceta, Escuela Técnica Superior de Ingeniería Civil, Universidad Politécnica de Madrid, 2014. [3] G. Stefano and J. Segovia. Notas del curso de Arte Minero I. Ecuador: Universidad del Azuay, 1991. [4] A. Maistri. Guía al Curso de Tratamiento de Minerales y a las Prácticas de Laboratorio. Ecuador: Universidad del Azuay, 1993. [5] O. Bustamante. Conminución de Minerales Trituración y Molienda. Colombia: Instituto de Minerales CIMEX, Universidad Nacional de Colombia-Sede Medellín, 2006. [6] E. Feijoo, C. Flores and B. Feijoo, "The Concept of the Granulometric Area and Its Relation with the Resistance to theSimple Compression of Rocks," 2019 7th International Engineering, Sciences and Technology Conference (IESTEC), Panama,Panama, 2019, pp. 52-56. [7] E. Feijoo and C. Iñiguez, “Corte en rocas y su relación con la resistencia a compresión simple”, RISTI, N.o E 30, pp. 59-67,junio 2020. [8] M. Galván. Mecánica de Rocas. Correlación entre la Resistencia a Carga Puntual y la Resistencia a Compresión Simple. Colombia: Universidad del Valle, 2015. [9] W. Marín. Evaluación de parámetros materiales de fractura en roca intacta. Colombia: Universidad Nacional de Colombiasede Medellín, 2017. [10]E. Feijoo and J. Padrón, “La resistividad de rocas y su relación con la resistencia a compresión simple en mina”, UCT, vol. 24, Núm. 99, pp. 61-67, abril 2020.

A cautionary note for rock avalanche field investigation – recent sequential and overlapping landslides in British Columbia

Large rock avalanches on glaciers are an annual occurrence in the mountains of western North America. Following an event, landslide investigators may strive to quickly arrive on site to assess the deposit. Satellite remote sensing imagery demonstrates that caution is warranted for on- site field assessments. We combine Landsat, Sentinel-1(radar), Sentinel-2 and Planet imagery to reconstruct the events of four recent double overlapping rock avalanche deposits in British Columbia. In our examples substantial precursory rock avalanches are closely followed (days - months) and buried by much larger landslides. We suggest that landslide investigators exercise caution when assessing fresh rock avalanches avalanche deposits in the field.

Investigations on radioelements occurrences in rocks in Kakuri Area of Kaduna North West, Nigeria

Detailed investigations on Radioelements occurrences in rocks in Kakuri Area Kaduna North West Nigeria were carried out in this work using Geochemical ground follow-up methods. The methods employed include Atomic Absorption Spectrometric (AAS) and Assay of rock samples from the area. Fresh rock samples were collected with hammer and identified as follows: Granite gneiss, Granite, Migmatites and Gneiss. Analysis was made on the powdered rock samples and histograms were plotted to determine the activity of Radioelement concentrations: Potassium, Thorium and Uranium in each of the samples analyzed. Results of the investigations showed high concentration of potassium (40K) and other Radioelements, thorium and uranium in the area. Generally, the results delineate the three Radioelements in terms of their anomaly pattern within the study area.Keywords: Geochemical Survey; Aeroradiometric Anomaly; Fresh Rocks; Radioelements and Kakuri Area

Application of Data Analytics Techniques to Establish Geometallurgical Relationships to Bond Work Index at the Paracutu Mine, Minas Gerais, Brazil

Analysis of geometallurgical data is essential to building geometallurgical models that capture physical variability in the orebody and can be used for the optimization of mine planning and the prediction of milling circuit performance. However, multivariate complexity and compositional data constraints can make this analysis challenging. This study applies unsupervised and supervised learning to establish relationships between the Bond ball mill work index (BWI) and geomechanical, geophysical and geochemical variables for the Paracatu gold orebody. The regolith and fresh rock geometallurgical domains are established from two cluster sets resulting from K-means clustering of the first three principal component (PC) scores of isometric log-ratio (ilr) coordinates of geochemical data and standardized BWI, geomechanical and geophysical data. The first PC is attributed to weathering and reveals a strong relationship between BWI and rock strength and fracture intensity in the regolith. Random forest (RF) classification of BWI in the fresh rock identifies the greater importance of geochemical ilr balances relative to geomechanical and geophysical variables.

Nanoscale Observations Support the Importance of Chemical Processes in Rock Decay and Rock Coating Development in Cold Climates

Conventional scholarship long held that rock fracturing from physical processes dominates over chemical rock decay processes in cold climates. The paradigm of the supremacy of cold-climate shattering was questioned by Rapp’s discovery (1960) that the flux of dissolved solids leaving a Kärkevagge, Swedish Lapland, watershed exceeded physical denudation processes. Many others since have gone on to document the importance of chemical rock decay in all cold climate landscapes, using a wide variety of analytical approaches. This burgeoning scholarship, however, has only generated a few nanoscale studies. Thus, this paper’s purpose rests in an exploration of the potential for nanoscale research to better understand chemical processes operating on rock surfaces in cold climates. Samples from several Antarctica locations, Greenland, the Tibetan Plateau, and high altitude tropical and mid-latitude mountains all illustrate ubiquitous evidence of chemical decay at the nanoscale, even though the surficial appearance of each landscape is dominated by “bare fresh rock.” With the growing abundance of focused ion beam (FIB) instruments facilitating sample preparation, the hope is that that future rock decay researchers studying cold climates will add nanoscale microscopy to their bag of tools.

Spectral properties of weathered and fresh rock surfaces in the Xiemisitai metallogenic belt, NW Xinjiang, China

Surfaces weathering of rocks in which mineral materials may be similar to or quite different from the minerals in the underlying parent rock completely control the reflectance spectra of the terrain. Our study of typical weathered and fresh rock samples from the Xiemisitai metallogenic belt, Western Junggar region, Xinjiang, found that weathering results in the formation of new materials that cause differences in the spectral features of fresh and weathered rock surfaces. Alterations induce variations in spectrum brightness, presence and intensity of characteristic absorption features, and spectral slope. Spectral differences between weathered and fresh rock surfaces are small for rhyolite, granite, and tuffaceous sandstone, but large for andesite, basalt, and diorite. Spectral changes in the 350–1000 nm wavelength region are attributed to alteration of iron oxides by atmospheric processes or secondary alteration of iron-rich minerals. Spectral features between 1000–2500 nm are caused by O–H vibrations, with features at 2200–2500 nm solely attributed to hydroxyl groups. The strongest Al–OH bands appear near 2200 nm, while Mg–OH bands are found near 2300 nm and 2350 nm. Results from this study can be used to better characterize and discriminate lithological units and potential mineral zones using hyperspectral and multispectral remote sensing techniques.

Crystals and Atoms

According to one magic crystal website, pyrite is a highly protective stone blocking and shielding you from negative energy. This may originate from Pietro Maria Canepario, who in 1619 cited Avicenna as stating that “if pyrite is worn on an infant’s neck, it defends him from all fear.” Other New Age sources maintain that pyrite can be beneficial when planning large business concepts because placing a piece on the desk energizes the area around it. Pyrite also reduces fatigue and is good for students because it is thought to improve memory and recall and to stimulate the flow of ideas. So you are certainly reading the right book . . . The magical properties of pyrite stem at least partly from the occurrence of pyritized ammonites (Figure 4.1) in ancient Egypt. Ammonites are fossils of coiled mollusks that became extinct at the same time as the dinosaurs at the end of the Mesozoic Era, about 60 million years ago. Ammonites got their name because they resemble coiled ram’s horns and the Egyptian god Amun (or Amon, Ammon, etc.) usually wore ram’s horns. The person responsible for this flight of fancy was Pliny the Elder, who called these fossils ammonis cornua or horns of Ammon. The golden pyritized ammonites were prized as lucky charms and worn as amulets in ancient Egypt. They are common today and may be readily collected from the beach at Charmouth in southern England, particularly after a storm has caused more fresh rock from the cliffs to tumble down onto the beach. The bright golden crystals of pyrite have fascinated humankind through the ages. The crystals display a variety of distinct shapes that make them extremely attractive. Indeed, pyrite may display the greatest variety of crystal forms of any common mineral. The great American mineralogist James Dwight Dana described eighty-five different forms, and the founder of geochemistry, Victor Moritz Goldschmidt, drew line drawings of almost 700 different pyrite crystals. In this chapter I show how the explanation of this extraordinary diversity of pyrite crystal shapes (or habits, formally) has helped reveal the nature of the material universe.