The Legnica deposit is one of the most prospective in the context of future lignite mining. Its extraction will be inseparable from the removal of the rocks of the overburden, the volume of which is very large. Due to the raw material properties, some of the rocks can be classified as accompanying minerals. The raw material identification of overburden sediments in the Legnica lignite deposit is insufficient. So far, they haven’t been the subject of detailed and comprehensive research to prove their usefulness. The article was a summary of the knowledge on this subject. The following should be included in the accompanying minerals: Quaternary sands and gravels, tertiary sands and clays (Poznan clays). They are present in two colour variants in the Legnica deposit - and fiery. The mineral composition of greenish-blue clays allows them to be included in illite-kaolinite- smectite varieties, in turn fiery clays as kaolinite-illite-smectite varieties. The tertiary clays are a very useful raw material for the production of building materials. In addition, they are potential mineral sorbents due to the nature of the association of clay minerals (occurrence of montmorillonite). They also show suitability for building waterproofing barriers. Quaternary gravels and sands, developed in the overburden Legnica deposit are differentiated raw materials. Some of them are raw materials for the construction industry. The glacial tills can be used as a component of ceramic mixtures. Tertiary sands can be used as a proppant material. The information on the raw material properties of these sediments will be one of the essential criteria for their treatment as accompanying minerals. Minerals accompanying those developed in the Legnica deposit should be exploited and deposited selectively. The creation of anthropogenic deposits accumulating these minerals will provide the possibility of their use for decades after the termination of operation.

The exploitation and processing of lignite in the Bełchatów region is connected with the formation of various mineral waste materials: varied in origin, mineral and chemical composition and raw material properties of the accompanying minerals, ashes and slags from lignite combustion and reagipsum from wet flue gas desulphurisation installations. This paper presents the results of laboratory tests whose main purpose was to obtain data referring to the potential use of fly ashes generated in the Bełchatów Power Plant and selected accompanying minerals exploited in the Bełchatów Mine in the form of self-solidification mixtures. The beidellite clays were considered as the most predisposed for use from the accompanying minerals , due to pozzolanic and sorption properties and swelling capacity. Despite the expected beneficial effects of clay minerals from the smectite group on the self-settling process as well as the stability of such blends after solidification, the results of physical-mechanical tests (compressive strength and water repellence) were unsatisfactory. It was necessary to use Ca (OH)2, obtained from the lacustrine chalk as an activator of the self-settling process It was necessary to use lacustrine chalk as an activator of the self-solidification process. The presence of calcium will allow the formation of cement phases which will be able to strongly bond the skeletal grains. Also, the addition of reagipsum to the composition of the mixture would contribute to the improvement of the physico-mechanical parameters. The elevated SO4 2– ion in the mixture during the solidification allows for the crystallization of the sulphate phases in the pore space to form bridges between the ash and clay minerals. The use of mixtures in land reclamation unfavourably transformed by opencast mining in the Bełchatów region would result in measurable ecological and economic benefits and would largely solve the problem of waste disposal from the from the operation and processing of lignite energy.

The Tertiary lignite formations in the Bełchatów deposit, along with coal, are built of plastic, weakly compact and loose rocks. Their physical and mechanical parameters, don’t pose operational problems. However, varieties of a different lithological character and physical-mechanical properties rocks, causing difficulties when mining the overburden rocks, appear within them. These include: Mesozoic limestones, Tertiary sandstones and conglomerates, as well as Quaternary iron feldspar rocks. The article features a lithological characterization as well as values of basic physico-mechanical parameters. They form the basis of the geological engineering classification and decide about their difficult workability. The possibilities of their raw material utilization were also discussed.

The article presents the problem of selecting the correct type of limestone for producing paving stones used to renovate the surface of Mariacki Square in Krakow. Due to using up local limestone deposits, imported limestones began to be used. The first one was a Turkish limestone with the trade name Lotus Beige. Despite substantial physical and mechanical parameters (compressive strength 134 MPa, water absorption 0.26%), after several years of use, the paving stone cracked and, as a result, fell apart into smaller fragments. Hauteville limestone from France has been selected for the following reconstruction of the surface. This limestone in the air-dry state was characterised by even higher parameters, i.e. compressive strength of 157 MPa, flexural strength at 16.9 MPa, Bohme Abrasion test at 15275 mm3, and water absorption at 0.23%. The tests also showed absolute frost resistance and high resistance to thermal shock. Unfortunately, after several years of using the surface of Mariacki Square, cracks and flaking of the rock material have been observed in terms of some paving stones. These cracks appeared within the so-called stylolite seams, which are a natural feature of limestone. Despite a very strict selection of materials, unfortunately, problems with the surface’s durability could not be avoided.

The domestic (Polish) lignite deposits, including the Bełchatów deposit, are classified as multi- mineral and multi-raw materials. Ensuring the possibility of using a significant part of all minerals present in this type of deposits should be a matter of priority for mines. Over several dozen years of operation, the Bełchatów Lignite Mine, based on its own experience in documenting and exploiting both the main mineral and accompanying minerals, as well as rock mass components that are not solid minerals, this mine has developed a new approach to the problem of the comprehensive use of deposit resources. The content of the article is an attempt to answer the question: do the applicable laws guarantee a comprehensive and rational use of mineral deposits whose resources are non-renewable? On the example of the area of the Bełchatów lignite deposit, the comprehensive and rational use of mineral resources was analysed. It was indicated that the reasons for their use result from the lack of appropriate organizational, economic and financial solutions. Particular attention was paid to the need to modify the licensing procedures for prospecting, documenting and extracting minerals. It seems reasonable to introduce multi-resource concessions, which are an important element of the circular economy. Therefore, proposals were formulated regarding the introduction of additional legal regulations and instruments of an economic and financial nature. These would be able to guarantee the comprehensive and rational use of most mineral resources.