The application of photo acoustic spectroscopy technique, PAS for its acronym in English, in the study of substances is so versatile that goes from the application in solids, liquids and gases. In others it has been shown that the technique PAS constitutes is one of the most effective means to study non-destructive in nature. Among other things, allows the study of the optical properties, thermal, mechanical, diffusion, permeation emissions, etc, into substances that by applying conventional techniques would be extremely difficult. In this paper we report the design and construction of a photoacoustic system that allowed us to characterize coal samples from Cerrejon Mine located in the Department of La Guajira, these samples were prepared in the form of pellets with a diameter of 1 cm and a thickness ranges from 1 - 5mm. Which have been characterized by the PAS technique, presenting study thermal diffusivity and thermal effusivity of coal, these results are confronted with other reported studies and performed a qualitative assessment of the thermal quality of the sample studied.