Automatically controlled ventilation of gas, dust, or radon content, step by step (radio) or continuous

Because of energy crises and the demand for a better environment underground, a study has been undertaken to determine whether automatic control of fans relative to diesel activity can be performed. Five different step by step regulation methods have been evaluated and two of them examined in detail by field tests. The temperature derivator method is recommended for use in starting and stopping crosscut fans and the radio method with ground plane antenna and coded signals is recommended for starting and stopping of gallery fans. To avoid overlap of radio waves between the ventilation moduli, it is necessary to use coded signals with different frequencies for each ventilation modulus