Explore the vast range of titles available.

Three-dimensional block models are the most widely used tool for the study and evaluation of ore deposits, the calculation and design of economical pits, mine production planning, and physical and numerical simulations of ore deposits. The way these algorithms and computational techniques are programmed is usually through complex C++, C# or Python libraries. Database programming languages such as SQL (Structured Query Language) have traditionally been restricted to drillhole sample data operation. However, major advances in the management and processing of large databases have opened up the possibility of changing the way in which block model calculations are related to the database. Thanks to programming languages designed to manage databases, such as SQL, the traditional recursive traversal of database records is replaced by a system of database queries. In this way, with a simple SQL, numerous lines of code are eliminated from the different loops, thus achieving a greater calculation speed. In this paper, a floating cone optimization algorithm is adapted to SQL, describing how economical cones can be generated, related and calculated, all in a simple way and with few lines of code. Finally, to test this methodology, a case study is developed and shown.

Grade control refers to the procedure to differentiate ore from waste in a mine. It is usually not easy to make such differentiation, especially in metallic mines where grades are very low, and miners have no visual or texture reference to distinguish the rock. This paper gives details of the grade control process that has been in operation during the last 10 years in the Corta Atalaya open pit, Riotinto, Huelva, Spain. The spacing of the blast boreholes, the sampling procedure, the laboratory analysis, and the software used to interpolate the data are discussed in detail. The amount of data generated is huge, as more than 120,000 boreholes are drilled each year, generating a high workload, as each borehole has to be sampled, each sample analyzed, and the results included in Recmin databases. These data are used to generate separation zones for waste and ore that are marked by topographers. This process is a key part of the mining sequence, directly impacting the economic results of the mine as better leverage of the deposit is obtained.

A fundamental aspect in the evaluation of mining projects is the classification of mineral resources, as it directly influences the definition of mineral reserves and affects both the planning and operational phases of the mine. Traditional methods employed in the industry are based on geometric or geostatistical criteria which, while constituting the fundamental basis of the process, may prove insufficient when applied in isolation to reflect the uncertainty inherent in the databases used for the evaluation of mineral deposits. As discussed throughout the article, this limitation can lead to an incorrect or imprecise assignment of resource categories. This work presents a methodology to integrate variables related to sample quality as an additional criterion in resource classification. This allows for the identification of areas with greater uncertainty and the adjustment of their categories more consistently with data reliability. The effectiveness of the proposed method is demonstrated through its application to a real case study, complemented by a comprehensive analysis of its implications and results.

Variogram calculation is a fundamental tool for studying ore grade data in mineral deposits. It allows the discovery of hidden structures within the data and preferential directions of mineralization where the geological continuity is longer. The variogram allows us to classify samples and to define both the search radii for interpolation and the use of kriging as an interpolation and resource classification method. It is not difficult to use it in one dimension; complexity increases in two dimensions as the necessity to search for possible grade anisotropies in all directions arises. Three-dimensionally it is even more difficult to try to define the parameters of lag, bandwidth, and tolerances that define the data of the variogram calculation algorithm. There are rules of thumb to help in the development, but a trial-and-error approach is used in order to find enough sample pairs to allow the generation of variograms truly representative of the data. In this paper, two strategies are shown to help in variogram construction, the use of variogram maps and the graphical representation of the pair search areas (cones or pencils). The freeware tool RecMin Variograms has been developed and is freely available for download at its website; it is easy to learn and use. R code based on RGeostats libraries is used to check the operation and results of RecMin Variograms. Applying geostatistics to mineral deposits is essential to know the areas with the highest grades, thus allowing exact planning of future mining exploitation and minimizing mine footprint and environmental impact.

Through an empirical analysis of the impact of determinants on energy efficiency and electricity prices using monthly data, we compare the outcomes of energy strategies in Ecuador and Peru from 2014 to 2023. OLS regression models with Newey-West matrices are applied in two contexts: Energy efficiency and energy prices. Energy efficiency is explained through variables such as the proportion of renewable energies, national income, and the international oil price. The results indicate that in Ecuador, the proportion of renewable energies is positively related to energy efficiency, whereas in Peru, energy efficiency mainly depends on the trend component capturing changes in productivity and the decline in fuel prices. Furthermore, electricity prices are sensitive to fluctuations in oil prices, especially in Peru, due to its dependence on thermoelectric generation. The energy strategies of both countries, including the integration of renewables and the management of fossil fuel costs, play crucial roles in determining energy efficiency and prices. This study provides a comprehensive view of how various economic and structural factors influence the performance of the energy sector in both nations, highlighting the differences in their approaches and outcomes.

Existing data on COPD prevalence are limited or totally lacking in many regions of Europe. The geographic information system inverse distance weighted (IDW) interpolation technique has proved to be an effective tool in spatial distribution estimation of epidemiological variables, when real data are few and widely separated. Therefore, in order to represent cartographically the prevalence of COPD in Europe, an IDW interpolation mapping was performed. The point prevalence data provided by 62 studies from 19 countries (21 from 5 Northern European countries, 11 from 3 Western European countries, 14 from 5 Central European countries, and 16 from 6 Southern European countries) were identified using validated spirometric criteria. Despite the lack of data in many areas (including all regions of the eastern part of the continent), the IDW mapping predicted the COPD prevalence in the whole territory, even in extensive areas lacking real data. Although the quality of the data obtained from some studies may have some limitations related to different confounding factors, this methodology may be a suitable tool for obtaining epidemiological estimates that can enable us to better address this major public health problem.

Three-dimensional block models are the most frequently used tool for estimating mineral resources and reserves within a mineral deposit. In open pit mining, the basis of mine design and the long term mining schedule is calculation of the ultimate pit limit. The ultimate pit limit is the pit with the highest profit value. Over the years, different algorithms have been developed that enable us to calculate the final pit: floating or mobile cone, floating cone II and its corrected forms, floating cone III, the Korobov algorithm and its corrected form, the Lerchs–Grossmann 2D algorithm (dynamic programming), and the Lerchs–Grossmann 3D algorithm (graph theory). All these algorithms have advantages and disadvantages. The floating cone method stands out for its simplicity, speed, and easy implementation, even for calculating a pit with a variable slope angle. The main drawback of this method is that it is unable to examine all possible combinations. For this reason, the algorithm does not consistently give optimal results, which is why it has required improvements over time. However, the improved methods still have some problems. To overcome these problems, a new algorithm called the floating cone IV method will be demonstrated in this paper.

In recent years, the introduction of specific software for the evaluation of geological resources and mineral reserves has increased significantly thanks to the use of block models capable of working with large databases and applicable to virtually all types of deposits. It is only in layered, tabular-shaped deposits where the use of block models poses certain drawbacks, not only in terms of visual representation but also during the process of interpolation. Other calculation methods for tabular bodies such as sections, polygons, and triangles work with 2D projections but not with 3D. The “Pentahedral” method described here is undoubtedly an innovative method that allows work to always be conducted in 3D, providing a fairly accurate representation of tabular bodies and making it possible to carry out calculations of resources and reserves using any interpolation method. It is demonstrated with figures and tables of the Carlés mineral deposit, a well-developed exoskarn gold deposit in northwestern Spain (Asturias) where the authors have worked extensively. The pentahedral method takes into account not only geological and stratigraphic data from the model interpolation, but also mining concepts such as “minimum thickness,” related to the minimum seam size that can be economically and technically mined, and “overbreak,” related to the dilution effect that appears during the mining process due to over-excavation.

In alpha-1 antitrypsin deficiency (AATD), the Z allele is present in 98% of cases with severe disease, and knowledge of the frequency of this allele is essential from a public health perspective. However, there is a remarkable lack of epidemiological data on AATD worldwide, and many of the data currently used are outdated. Therefore, the objective of this study was to update the knowledge of the frequency of the Z allele to achieve accurate estimates of the prevalence and number of Pi*ZZ genotypes worldwide based on studies performed according to the following criteria: 1) samples representative of the general population, 2) AAT phenotyping characterized by adequate methods, and 3) measurements performed using a coefficient of variation calculated from the sample size and 95% confidence intervals. Studies fulfilling these criteria were used to develop maps with an inverse distance weighted (IDW)-interpolation method, providing numerical and graphical information of Pi*Z distribution worldwide. A total of 224 cohorts from 65 countries were included in the study. With the data provided by these cohorts, a total of 253,404 Pi*ZZ were estimated worldwide: 119,594 in Europe, 91,490 in America and Caribbean, 3,824 in Africa, 32,154 in Asia, 4,126 in Australia, and 2,216 in New Zealand. In addition, the IDW-interpolation maps predicted Pi*Z frequencies throughout the world even in some areas that lack real data. In conclusion, the inclusion of new well-designed studies and the exclusion of the low-quality ones have significantly improved the reliability of results, which may be useful to plan strategies for future research and diagnosis and to rationalize the therapeutic resources available.

The α-1 antitrypsin (AAT) protease inhibitor PiMZ is a moderately deficient genotype, until recently considered of little or negligible risk. However, a growing number of studies show that MZ carriers have an increased risk of developing lung and liver diseases, if exposed to smoking or other airborne or industrial pollutants, and hepatotoxic substances. We used the epidemiological studies performed to determine the frequencies of PiM and PiZ worldwide, based on the following criteria: 1) samples representative of the general population; 2) AAT phenotyping or genotyping characterized by adequate methods, including isoelectric focusing and polymerase chain reaction; and 3) studies with reliable results assessed with a coefficient of variation calculated from the sample size and 95% confidence intervals, to measure the precision of the results in terms of dispersion of the data around the mean. The present review reveals an impressive number of MZs of more than 35 million in 74 countries of the world with available data. Seventy-five percent of them are people of Caucasian European heritage, mostly living in Europe, America, Australia and New Zealand. Twenty percent of the remaining MZs live in Asia, with the highest concentrations in the Middle East, Eastern¸ Southern, and South-eastern regions of the Asian continent. The remaining five percent are Africans residing in Western and Eastern Africa. Considering the high rate of smoking, the outdoor and the indoor air pollution from solid fuels used in cooking and heating, and the exposure to industrial dusts and chemicals in many of these countries, these figures are very worrying, and hence the importance of adequately assessing MZ subjects, recommending them rigorous preventive measures based on the adoption of healthy lifestyles, including avoidance of smoking and alcohol.