In the Motongkad prospect, East Bolaang Mongondow Regency, North Sulawesi Province, Indonesia, an epithermal gold mineralization occurred, hosted in andesitic-basaltic breccia, lava and tuff members the middle Miocene volcanic rock (Tmv). The Volcanic Rock is intruded by andesite dikes and contains fine quartz veins. Gold, silver, and pyrite found in the quartz veins.
This study consists of two main stages, field works and laboratory works. The field works were performed in whole area of the Motongkad prospect, where fresh and altered rock and mineralization samples were collected randomly, selectively, and systematically from outcrops as well as from a test pit. The laboratory works include petrography, X-ray diffraction (XRD), ore microscopy, and chemical analysis using the atomic absorption spectrometry (AAS) method.
The study area is arranged by three lithology units. Stratigraphically, the units are andesite rhyolite and tuff. The hydrothermal alteration in the study area are classified in five zones, namely: quartzsericite, quartz-sericite-clay, quartz-calcite-sericite-chlorite, quartz-calcite-sericite, and quartz-calcite- kaolinite. Motongkad prospect mineralization consists of two types, namely the vein type and the disseminated type. The ore minerals found in the Motongkad prospect are gold, pyrite, chalcopyrite, sphalerite, covellite, chalcocite, bornite and tennantite. We conclude that gold mineralization and its associated minerals in the Motongkad prospect are hydrothermal mineralization with epithermal characteristics.
Based on the results of mineragraphic analysis, there are two types of gold-bearing minerals found, namely native gold minerals and electrum, which are generally hosted by pyrite. Based on the distribution map of alteration and mineralization that has been made, it is recommended that the company wish to conduct mining with the highest gold content in the quartz-sericite and quartz-sericite- clay alteration zones, which are in the range of 0.83–1.07 g/t.

The “Sulmierzyce-Odolanów” study area analyzed in the present paper constitutes an example of the presence of deep Zechstein metallic mineralization in the Fore-Sudetic Monocline. Unlike the shallow deposits which are being mined nowadays, these types of areas were not previously considered in terms of their possible extraction. However, in recent years, due to the development of modern mining technologies, this situation has changed and these areas have become prospective for the future documenting of mineral deposits. The threshold parameters delimiting an ore deposit, recommended for use when preparing geological documentation and not compulsory, have been established by the regulation of the Minister of Environment. In the case of stratabound Zechstein deposits they take the equivalent percentage and productivity of only two metals, i.e. copper, as the main useful component, and silver into account. This leads to the underestimation of the resources of ore which also contains other metals, including zinc and lead, which is particularly disadvantageous in the case of deep deposits, which from an economic standpoint, it is advisable to focus on their richest parts and to document, and in the future to extract all the useful metals. Also, the regulation of the Minister of Environment does not take into account the fluctuations of the market prices of metals over time, the impact of which on the equivalent content and productivity of these elements in the deposit is considerable. This paper presents the authors’ own formulas intended to calculate polymetallic equivalent content and productivity taking the share of four elements in the ore into account: copper, silver, zinc and lead. They also enable determining these values for arbitrarily selected time intervals and tracing their changes over time. Apart from the quality parameters it is also possible to calculate the value of mineral resources in the deposit expressed in American dollars per one square meter of its area for each selected time interval. The calculations used the results of chemical analyses of historical drill cores originating from the studied area. A total of 135 historical holes located within its boundaries were analyzed. Based on the obtained figures, the time-varying resources of the polymetallic equivalent (Cu-Ag-Zn-Pb) were estimated along with their market value expressed in American dollars for each year in the time interval of 2012–2016.

This work aimed to verify forecasts of temperature and mineralization of the Lower Jurassic and Lower Cretaceous waters in the Polish Lowlands, based on new geological information. In the first part of the articles series, entitled Verification of geothermal conditions in the Polish Lowlands based on data from new drilling performed in the years 2000–2022, an analysis of geothermal conditions is presented, while this work focuses on hydrogeochemical parameters, such as temperature in the top of formations and water mineralization. For this purpose, data from the Central Geological Database (CBDG), the Central Bank of Hydrogeological Data – HY DRO Bank, and from previously published scientific and research works were used. In the years 2000–2023, twenty-four exploration wells with a depth exceeding 1000 m below ground level were drilled and documented in the Polish Lowlands, providing information on the temperature and mineralization of waters taken from the Lower Jurassic or Lower Cretaceous formations. The assessment of spatial changes, as in the first part of the work, was performed with the use of QGIS Desktop 3.24.1 software, which is geoinformation software (GIS ) that allows viewing, editing, and analyzing spatial data and the creation of maps. The presented analysis made it possible to make a spot, local correction of the projected course of the isoline in relation to the maps published earlier in the Atlas of geothermal resources in the Polish Lowlands. Mesozoic Formations developed in 2006, edited by Wojciech Górecki.

In 2011, the Miedzi Copper Corporation (MCC) initiated its exploration program involving deep Cu-Ag deposits in the Fore-Sudetic Monocline. A very vast study area was adopted, along with the use of a wide range of research instruments. In the years 2011–2013 the exploration of MCC involved 21 concession areas. The location of concessions for exploration as well as exploration and prospecting was based on the known prognostic and hypothetical areas with confirmed contact of the Rote Fäule facies with the reduced facies, placed in the proximity of the Zechstein elevations. In 2012 and 2013, historical boreholes drilled mainly by the petroleum industry were logged, and in cases where the preservation of rock material allowed, samples were collected for chemical analyses. Moreover, a wide range of specialized examinations was performed, involving organic chemistry, coal macerals, vitrinite reflectance and petrography, with a particular emphasis on the Rock Eval method. The latter allows the presence of the so-called strong Rote Fäule associated with the presence of the richest mineralized horizons to be established. It was equally important for the purpose of exploration to perform the reprocessing of geophysical data using the innovative method of effective reflection coefficients. This allows transforming a conventional seismic image into an impulse form of seismic records, meaning a temporal sequence of coefficients, whose sections can be correlated with the logs of historical boreholes in order to trace the course of lithological series. This method provides a much higher accuracy for determining structural elements crucial for exploration than before, suggesting the presence of various tectonic phenomena important for mineralization. As a result, a more detailed mineralization distribution model was obtained and the so-called sweet spots were pinpointed, becoming an object of further drilling exploration. The number of active concessions was reduced to 6, which resulted largely not just from the absence of ore, but also from economic premises. The drilling program initiated in 2013 and still continued today allowed the discovery and preliminary documentation of three copper and silver deposits in the Fore-Sudetic Monocline. These are the Mozów and Sulmierzyce deposits, where the presence of prospective areas was previously recorded, as well as the Nowa Sól deposit, discovered in the so-called green field, where no ore exploration was previously conducted. At the current stage of identification, each of these deposits contains resources exceeding 5 million tons of equivalent copper, and the performed economic analyses indicate the viability of their extraction using the modern methods of shaft sinking, air conditioning and waste management.