Design of an automated cyanide gas detection and control system for a gold mine

Abstract

Cyanidation is an essential process that uses sodium cyanide in gold production. The use of sodium cyanide poses the risk of cyanide gas (HCN gas) poisoning, which has been a challenge in gold mines for many years. A gap exists in the literature regarding systems that simultaneously detect and control dangerous levels of HCN gas. Significant literature sources report HCN gas monitoring systems that detect and record gas concentration levels in the air at different intervals. Furthermore, most reported treatment methods focus on controlling free cyanide in processing effluent, not the HCN gas. Therefore, this paper presents the design of an automated, real-time HCN gas detection and control system for a gold mine using the Internet of Things (IoT). The designed system can detect any rise above the OSHA legal airborne HCN gas permissible exposure limit (PEL) of ten parts per million. In case of detection, the sensor sends a signal to the microcontroller, which triggers a warning alarm to alert workers to evacuate the area. Simultaneously, a signal is sent to the solenoid valve to close the cyanide tank supply. The DC fan immediately provides an air supply that neutralizes the toxic levels of HCN gas.