Mining activity in the town of Bechar in southwest of Algeria was definitively completed in 1975 by generating artificial mountains known as coal slag heaps. These heaps cumulate a volume of 3767330m3, and occupy an area of 167.71 ha. The miners and former inhabitants of the Bechar region and particularly in the town of Kenadsa, were affected by the disease Silicosis caused by direct exposure to pure silica dust or the inhalation of dust. The development of urban fabrics has now resulted in some slag heaps being located very close to built-up areas, or squarely in the middle. These slag heaps constitute permanent sources of risk of environmental pollution and possible deterioration of the health of the local population. This study aims to verify two points: the first is to test, through a survey, the different risks felt by the inhabitants near these slag heaps on their health and their daily life; the second is to analyze, through on-site measurements, the reliability of use of these slag heaps in construction materials on the thermal behavior of buildings. The results of the survey highlighted the great risk generated by the presence of these slag heaps on the health of the inhabitants and which is worsening with the climate which has become drier (absence of rain in recent years). On-site measurements on a building constructed from slag heap concrete bricks showed fairly good insulation of this material and its good contribution to improving thermal comfort.