FIELD: measurement technology. ^ SUBSTANCE: several gamma-radiation sources are mounted onto closed frame of balance. Corresponding gamma-ray detectors are mounted under the frame. Transporter is placed between detectors and sources. Output voltages U0 and Ui of gamma-ray detector are measured at presence and absence of material. Values of U0 and Ui are introduced into data processing unit which is connected gamma-ray detector. Speed Vi of transporter-placed transportation tape is measured by means of meter and value of Vi is introduced into data processing unit which is connected with speed meter. Total weight W of materials subject to transportation during specific period of time is calculated from relation Differences in nuclear weights are specified by the fact that value of K factor using for calculation of formula F=K*Ln(Ui/U0) can be calibrated depending on changes in loads of materials, different positions of materials located onto the band of transporter, different shape of accumulation of materials
