# Utilisation of Mining Waste for Production of Ceramic Tiles
## 1 Introduction  
Mining waste management represents one of the most significant environmental challenges in the mineral extraction industry, particularly in regions with intensive mining operations. The issue is especially pressing in areas with multiple mining activities, where different types of waste accumulate over time. In Poland, copper mining and processing alone generate approximately 28 million tons of post-flotation waste annually, while lignite mining produces substantial amounts of clay waste, creating a complex waste management challenge in the region of Lower Silesia [1, 2, 3, 4]. These wastes are currently stored at the only active facility--the Mining Waste Disposal Facility (MWDF) \"Zelazny Most\". It is one of the world's largest hydrotechnical structures of this type [5]. It shapes groundwater and surface water's hydrochemical and hydrodynamic conditions over several square kilometres of surrounding areas. Limited storage capacity and increasing evidence of the adverse impact of post-flotation waste on the environment [6, 7, 8, 9] have created an urgent need to perform research dedicated to their potential utilisation. Post-flotation waste, subjected to long-term exposure to atmospheric factors, undergoes dissolution, which consequently leads to a rise in the concentration of potentially toxic compounds in the immediate surroundings. Less than 5 km southwest of \"Zelazny Most\" is the MWDF \"Gilow\"--a smaller storage facility that has already been decommissioned (1968-1980, mainly from the \"Lubin\" mine). It has also been the subject of many research studies and reports, including the mineralogical and chemical composition, as well as a description of pollutants released into the environment [10, 11, 12, 13]. The granulometric composition and selected physical properties of post-flotation sediments accumulated in the \"Gilow\" facility vary widely [11]. This depends on the type of rock in which the original copper ore occurs (different mines) and its mechanical processing technology. In the <2 \(\upmu\)fraction of post-flotation sediments, there are clay minerals from the group of hydrated mica (illite), smectite and mixed-packet illite-smectite minerals. Fine-grained carbonate waste (mainly dolomite and calcite) is currently used to seal the bottom of the disposal site, preventing the infiltration of mineralised supernatant water into its substrate [14; 15]. Waste with a majority share of sandstone is generally not reused. So far, several directions of their potential application have been studied, e.g., for the production of cement [16], porous aggregates, cellular concrete and foam concrete, magnesium-calcium fertilisers, road construction and mining technologies [17; 18], as well as in ceramic tile production [19; 20]. For various reasons, none of the directions identified so far has created the possibility of profitable and comprehensive usage of significant amounts of flotation waste. Currently, the primary techniques for the management of sediment waste from inactive disposals in Poland are reclamation and afforestation. It is, in fact, a loss of a potentially valuable source of raw material, e.g., for the ceramic industry. Additionally, unexploited landfills have a negative environmental impact, including the occupation of large natural areas (over 274 ha of surface), and, in their current form, do not fulfil any utilitarian nor natural function and is essentially a wasteland disfiguring the landscape [21; 22]. However, these approaches to waste management have faced limitations in terms of economic viability, technical feasibility or scale of waste utilisation [23]. The ceramic industry, particularly tile production, presents a promising alternative that has not been fully explored, especially for the simultaneous utilisation of multiple waste streams. For instance, while the presence of potentially toxic elements in reclaimed coal waste poses a risk, it also indicates that careful processing could yield valuable raw materials for ceramics [24].