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The Cu-Ag Lubin deposit belongs to the Lubin-Glogow Copper District (LGCD), which is located in south-western Poland. Copper mineralization occurs in three main lithological units: sandstones, shales and carbonates. A characteristic feature of these deposits is the occurrence of elevation and depression of the Weissligend top, which are convex structures in the form of sandy swells that are probably relics of eolian dunes from the Rotliegend period. These zones usually have a significant impact on the quality parameters of the deposit (thickness of the deposit, copper abundance and copper content), mainly due to the reduction or total disappearance of the shale series at the elevation peaks. The average unit copper content in the entire economic resources varies from approximately 50 kg/m2 in the north-eastern and eastern part of the deposit to approximately 190 kg/m2 in the north-western part of the deposit, with a coefficient of variation of 58%. Due to these premises, the object of the research was to analise the homogeneity of the Lubin deposit in terms of copper abundance using statistical procedures. For this purpose, the area of the deposit has been arbitrarily divided into several dozen areas, taking into account the presence of elevation and depression zones. The research was conducted for 4 cases: in the whole interval of the economic resources, and with the distinction between main lithological units (sandstone, shale and carbonate series). Kruskal-Wallis and Mood's tests showed statistically significant differences between the medians of copper abundance in the studied areas in each of the considered cases. In order to obtain information on which areas differ in a statistically significant way, the Games-Howell Multiple Range Test was carried out. It allowed to distinguish over a dozen homogeneous groups for the copper abundance in the entire economic resources of deposit, in the sandstone series, shale series and carbonate series. The most numerous homogeneous groups contain up to 7 areas. In many cases, areas belonging to the same homogeneous group are not adjacent. It allows for determining the apparent heterogeneity of the deposit in terms of copper abundance. [ABSTRACT FROM AUTHOR]

The Polish Cu-Ag deposits on the Fore-Sudetic Monocline are characterized by the occurrence of sedimentary structures called the elevations of the Weissligend top. These are elongated forms in the shape of sandy shafts whose occurrence affects the change in the value of deposit parameters (including reduction of the shale series's thickness). In the Lubin deposit, these elevations are the least well-known among all such structures in the entire Lubin-Glogow Copper District (LGCD). The basic material of the study was the results of systematic sampling of the deposit in mining excavations conducted by the geological service of the mine. They contain information about the location of the sample in space, thickness of individual lithological units at sampling sites, and the content of main elements and accompanying components in the samples taken. The article presents the results of research on correlation relationships between the values of basic deposit parameters (thickness of the shale series, copper abundance and average copper content in the economic resources) and the distance from the elevation peaks. These peaks were designated by the author arbitrarily on the basis of isoline maps of the thickness of the shale series. The distance of each point to the peak of the elevation was calculated using a script written in Python according to the principles of analytical geometry. The next step was to select several test areas for which a correlation and linear regression analysis was performed. The obtained results indicate a statistically significant, but moderately strong, positive correlation between the shale series thickness and distance from the peak with linear correlation coefficients from the range of 0.4-0.6 and the determination distance from the elevation peaks, this coefficient takes on smaller values and the direction of correlation depends on the selected area (some elevations are rich in copper, while others may be completely gangue). The correlation results of the average copper content in the balance sheet and the distance from the peak of the elevation show a very weak or complete lack of connection between these parameters. Additionally, the polynomial and nonlinear regression analysis performed for all parameters showed only insignificant improvement in correlation strength. [ABSTRACT FROM AUTHOR]

One of many factors determining the success of the future exploitation of oceanic polymetallic nodules is the amount of resources and the accuracy of their estimation. The potential exploitation requires accurate estimation of resources classified as measured resources according to the Australian JORC Code (The Joint Ore Reserves Committee Code). The issue of the accuracy of polymetallic nodule resources estimation was analyzed in the area of the Clarion-Clipperton Fracture Zone in the Pacific administered by the InterOceanMetal Joint Organization (IOM), the contractor of the International Seabed Authority (ISA) since 2001. The area of about 4 200 km2 selected for the analysis is one of the most prospective ones due to the abundance of nodules. The analysis was based on samples collected from the ocean floor using a box corer operated from the research ship. The average distance between sampling sites was about 8 km. The assessment of the accuracy of estimates was made for 15 square calculation blocks with a side of 17 km and an area of 300 km2. They roughly correspond to the areas of annual exploitation, assuming that the average abundance of wet nodules is 10 [kg/m2] and the annual production is 3 million tons. The use of geostatistical block kriging enabled to determine relative standard kriging errors as a measure of the accuracy of estimates of nodule resources. To minimize the risk of mining investment, it was assumed that the nodule resources estimation error in the case of calculation blocks corresponding to the areas of annual exploitation must not exceed 5%. The calculated estimation errors range from 10.6% to 26.6% (with a median equal to 13.1%) and are much higher than the assumed threshold value of 5%. The low accuracy of polymetallic nodule resources estimation is due to the small volume of samples collected by box corer, the large distance between sample collection points, and a relatively high regional (with a coefficient of variation close to 40%), and local variability in the abundance of nodules (discontinuous variation) as indicated by the nugget effect in the geostatistical semivariogram. Subsequent simulations have confirmed that achieving the assumed accuracy would require the collection of a large number of samples from the ocean floor, which is unrealistic given the huge labor intensity and high costs. The only rational way to achieve the assumed accuracy is to combine resource estimates based on box corer sampling method with an additional polymetallic nodule resources estimation based on bottom photographs, taken by the research ship or AUV (Autonomous Underwater Vehicle). [ABSTRACT FROM AUTHOR]

The Cu-Ag deposit exploited in the Lubin-Głogów Copper district (LGCD) in Poland is located in the Permian Rotliegend (sandstones) and Zechstein (shale and carbonate rocks) formations. The three main lithological series are not internally homogenous; within them, a total of 16 individual lithological units can be determined. The differentiation between lithological, mineralogical and geometallurgical ore properties is a criterion used to distinguish between main and individual lithologies in the deposit area. A systematic collection of chip samples in mine workings is carried out separately for each individual unit in the vertical profile with horizontal spacing of 20 m. The Cu content is determined for each of the collected samples. When it comes to the main lithological units, significant differences in the average content of the main metals (Cu, Ag) and accompanying elements (e.g. Pb, Co, and Zn) are observed. The use of classical statistical methods allowed examining geochemical similarities between individual units separately for each main lithological unit. For this purpose, the compatibility of empirical distributions, the equality of medians, and the average contents of Cu in individual lithological series were examined. The test results allow combining some of individual units into a single geochemical domain. Such a procedure significantly simplifies and facilitates the 3D geological modeling of the deposit. [ABSTRACT FROM AUTHOR]

The subject of the study was to characterize three deposit parameters of Pacific polymetallic nodules (the content and the abundance of nickel and the nodule abundance) using classical statistical methods. The input data points come from 448 sampling points of a bed area of about 48,000 km2 in the Clarion-Clipperton fracture zone (approx. 1,000 km west of the coast of Mexico). The sample points formed a pseudoregular grid with an average distance between them of about 10 km. On the basis of these, the basic statistical values were calculated. Variability of the parameters was on a level from low to high content of nickel in the case of abundance of nickel and nodule abundance. Errors in estimating average parameter values did not exceed 10% in any case. The analysis of the correlation and regression showed a strong correlation between the nodule abundance and the nickel abundance and were caused by a very low relative variability of nickel. This knowledge can be used in the calculation of the nickel resources without the need for large amounts of chemical analysis of the nickel content. The Games-Howell test used for seven artificially designated sub-areas distinguished two homogenous groups in terms of nickel content and two homogenous groups in terms of nickel abundance. [ABSTRACT FROM AUTHOR]