Mining activities have resulted in the existence of dumps, which generally present a perpetual danger of moving and transforming toxic elements. The experimental study was carried out in Nizna Slana (Slovakia) where the main source of emission was the iron-ore mining–processing factory focused on siderite mining. Siderit from Nizna Slana is highly ferrous with an increased level of the Mn content. Among the undesirable impurities on the deposit are mainly As, S, Pb, and Zn. According to the environmental regionalization of the Slovak Republic, the surveyed area represents a region with a slightly disturbed environment. The BIOLOG® Eco plates method was used for ecotoxicological evaluation of contaminated soils, where soil enzymes (acidic and alkaline phosphatase and urease) were also monitored in soils and soil contamination was evaluated according to Hakanson (1980). Based on the results obtained, it can be concluded that the content of Hg, Cd, Cr, Cu, As, Fe, Mn, and Mg is above the toxicity level. As, Fe, Mn, and Mg are the most serious pollutants in the area under investigation, and their pronounced excess indicates contamination, where harmfulness and toxicity can be expected. Based on the evaluation of the contamination factor and the degree of contamination, the soils in the emission field of old mining works are very highly to slightly contaminated with heavy metals. The experimental results in the real environment showed that the activity of soil enzymes showed considerable differences, and, regarding the functional diversity of soil microorganisms, we have not seen significant spatial variability.