Mine shaft conveyance load-monitoring system

Technology to enhance safety features for mine shafts and elevators is being investigated by researchers at the US Bureau of Mines. This paper describes the development of a slack rope sensor and data transmission and collection hardware to sense conditions and acquire data directly from the hoisting conveyance. A new type of load cell senses wire rope tension at the conveyance. A multichannel signal processing board has been designed and fabricated and is undergoing both static testing to evaluate long-term stability and dynamic testing under simulated hoisting conditions. Analog signals from the sensors are sampled at 100 ms intervals. Data transmission between the moving conveyance and the hoistroom is accomplished via a 2,400-baud FM-radio modem. Data are acquired at the conveyance or in the hoistroom through a serial communications port on a laptop computer. Software has been written to acquire, analyze, and process the data. The resulting system will allow operating personnel to determine conveyance load and thus rope tension and "slack" or "overload" rope conditions, in relation to conveyance position in the hoistway.