Conveyor belt is one of the most common types of continuous handling equipment used for moving rocks of various sizes horizontally or inclined. From researches done in the exploitation of mineral resources and rocks and from the Strength of Materials calculations in this paper is observed above the conveyor sizing and other elements of the transporter requires knowing how belt traction forces (tensions thereof) varies on the conveyor length. In all cases the operation of the conveyor belt must be provided without engaging the slip phenomenon and limiting its displacement (between sets of rollers) so conveyor can operating at optimum parameters. The materials that make up a conveyor belt can be divided into two categories: materials for coating plates or outer shell and a resistance part, areas with inserts that can be textile and steel cables. Because the bands are subjected to tensile efforts and wear phenomena we determine the maximum strength they can operate without going into permanent deformation regime. Conveyor belt dimensioning calculations and other elements of a conveyor varies depending on its length and the carrier operating situations. We can see, also, that sizing conveyor belt and other conveyor components require knowledge of how belt traction forces (tensions thereof) varies along the length of the conveyor. The tensions from the conveyor belt will be study for the climb section and for the descend section. It mentions that the specific resistance to motion of the belt on full branch, consisting of resistances due: current material deformation, rotation rollers camps because pressing rubber layer and roll belt and belt bending. Since current material strength due to deformation and bending belt represents a large percentage of total specific resistance to motion, it follows that resistance decreases with decreasing displacement belt between rollers and increase with the effort in belt, respectively. This explains that resistance decreases with increasing length of conveyor (especially when its initial stretch is great), and with increasing conveyor tilt too. Also, we observe, from the values of forces calculated in the paper, that the resistance to rotation of the roller bearings decreases with increasing load on the roll, hence the values adopted for specific resistance to movement can be more larger on the empty branch than on the full. Knowing how to calculate resistances to motion of the belt, you can fix that occur belt efforts through the points made on the contour method, starting point of the drum motor development and ending point of winding it. These movement resistances calculated for empty and full branches are needed to precisely determine the installed power of the conveyor belt.

This paper presents a method for determining the nature of the material (cool or sterile) running on high-capacity mining belt from basin of Oltenia. When an electromagnetic radiation that propagates in the air meets the separation surface with another environment suffers, among other things, the phenomenon of reflections (diffuse and specula). The intensity of reflected radiation depends on the optical surface properties of the encountered material. On this fact is based the possibility of identification of certain components of the mixture, if the optical properties are considerably different from other components. The method proposed in this paper is based on measuring the reflectance for different regions of the visible and near infrared spectra for samples of coal and sterile, dry and wet. The system for determining the nature of the excavated material mainly consists of an optical head (reflectance sensor) and an ultrasonic head (remote sensor). From experimental observations we see that the reflectance values of coal can be separated from those of sterile, which confirms the possibility of coal detection using the difference in reflectance. The limit of demarcation between reflectance of coal and different types of sterile is influenced by disturbing factors that occur at the plant operating detection under practical conditions such as: material humidity, the variability level of the material on the conveyor belt, the existence of a light background ambient. The method for determining the nature of material (coal or sterile) that circulates on high capacity belts creates real prerequisites of material excavated in conjunction with the possibility of taking quick and effective decisions in the distribution nodes from the coal careers. Key words: electromagnetic radiation, reflectance, coal, remote sensor, detection.

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