Integration of collision avoidance system into scraper winch signalling system

Abstract

The use of scraper winches poses a high risk in the mining industry. Using scraper winches has resulted in 877 injuries and 23 fatalities for the past seven years alone (excluding near misses caused by scraper winch operations, as they are not included in mine safety reports). The accidents occur around the rope, snatch block, winch, and scraper. Most accidents are caused by the scraper (Gold: 33% and Platinum: 21%) and the rope (Gold: 30% and Platinum: 31%). 36% of these aforementioned incidents are caused by employees entering the gulley’s (scraper path) and winch operators commencing the scraping of ore unaware of other employees in the gulley. This does not only affect safety but also productivity and costs. To increase safety in scraper winch operations, a Collision Avoidance System (CAS) is required. In the event of an emergency, this device will prevent anyone from approaching the scraper path and will immediately trigger the stoppage winch. The main aim of the study was to develop the reference framework for a scraper winch CAS and determine the benefits of implementing the system in a mine. This study was aimed at enabling OEMs to understand what was expected of the system while developing it, as well as to give miners an idea of what to anticipate from the system's deployment. To accomplish this, a literature review of currently available PDS/CAS technologies, PDS/CAS systems already on the market, and electric winch control systems was conducted. The CAS is essentially made up of the following five components: a personnel tag, proximity sensor, visual & audible signalling unit, system controller, and an AC contactor. These components integrate to form a system that prevents winch-to-pedestrian collisions through automatic personnel detection, audible & visual warnings, and winch tripping. Proximity sensors transmit RF signals, which are then detected and measured by the personnel tags worn by employees. The interface module is the core of the CAS. It serves to control the system by receiving information from the proximity sensors and tags, also it generates an exclusion zone within the hazard zone to allow the winch operator to operate the winch without tripping it. Because the proximity detection system is linked to the winch control system, when the danger zone is breached, an AC contactor de-energises the coil, cutting-off power, and automatically tripping the winch. Based on the simulation results performed, implementing the CAS for scraper winch operations will reduce the number of incidences in a stope by 33% per year which will lead to an increase in productivity of 277 tons/day and profitability of R89 million/year.