IM 2019 July 19 | Page 16

VENTILATION systems – in addition to improve the operating environment for miners – it will not solve all issues. “The mine will still need to deal with the efficient removal of blast & strata gases and heat since miners still need to go underground to operate and service the fixed equipment and operating fleet of production equipment,” Gribbons said. The strata gas liberated with the removal of rock can be benign, toxic or, at times, deplete the available oxygen below acceptable levels, according to Gribbons. At greater depths, the air is denser and continues to pick up heat from exposed rock, he added. Kim Trapani, Ventilation Engineer, and Pedram Rostami, Project Manager, Mining, at Stantec, agreed with Gribbons’ assessment. “In mines where electric vehicles are in operation, there is not a legislation airflow per brake horsepower but rather a good air quality needs to be maintained (this needs to consider parameters such as temperature, silica dust, oxygen content, carbon dioxide content, etc). The main issues with deep mines will inevitably still be addressing the heat, mainly from strata, and the cooling/refrigeration challenges,” she told IM. Howden’s Sales Director – Mining, Peter Terkovics, said there are still some unknowns when it comes to how battery-electric vehicles will impact underground ventilation requirements. “How the transition from diesel to battery- electric vehicles affects mine ventilation design is yet to be seen because battery-electric vehicles are still an early-adopter technology,” he told IM. “With that said, newer vehicles with lower air requirements may reduce the volumetric requirements for some phases of mine operations but heat control and blast clearing may become the new drivers for underground ventilation and overall capacity requirements may not change too much.” Mines will still have to deal with the installation of underground booster fans and methods to chill the ventilation air so miners can continue to work in these environments, according to Gribbons. Both of these are “massive energy consumers”, he said. Against this backdrop, the ability to regulate or reduce ventilation could have a marked impact on overall operating costs. This has led to the advent of sophisticated monitoring systems that connect to other 14 International Mining | JULY 2019 sensors and equipment to ensure optimal and efficient distribution of air to the active areas of a mine. Maestro specialises in providing such solutions, with its Vigilante AQS™, Plexus PowerNet™ and Zephyr AQS™ systems deployed in over 125 mines globally. While ventilation on demand (VoD) may be the ultimate solution for modern underground mines that can afford it, Gribbons said air quality monitoring, alone, can improve productivity by allowing miners to return to the face quicker and safer after a blast. “For example, Rio Tinto’s Diavik mine reported a productivity improvement of 60 minutes per day by using the Vigilante AQS for monitoring blast gases,” he said. “These simple improvements can result in a return on investment of days to weeks since the solution is relatively inexpensive and simple to install.” Vigilante AQS is a third-generation underground mine air quality monitoring station designed with an improved communication platform. The modular design provides flexible integration with any SCADA, PLC, DCS, PLS or HMI system, according to Maestro. Users can plug the station into a network switch, configure the settings via the built-in web pages and start measuring, the company says. Once these monitoring solutions are installed, mines can bolt on additional ventilation controls requiring greater capital expense and planning – including turning on and off auxiliary fans from surface – to achieve greater energy savings. Demand The next step is VoD. “VoD systems can be operated to further reduce the ventilation requirement as long as the air quality where personnel are working underground is not compromised,” Stantec’s Trapani and Rostami said. The decision to invest in such a VoD system often boils down to the return on investment it can offer, according to Trapani and Rostami. “[It] is typically driven by the size and duration of the overall mining operation, with longer and bigger operating mines justifying the investment of these more expensive technologies and better systems,” Trapani and Rostami said. Such mines may have noted the recent tie-up between Mobilaris and Epiroc, which has led to the integration of the Mobilaris Mining Intelligence (MMI) and Epiroc Serpent Ventilation platforms. MMI is an information management platform that gathers data about where people, equipment and vehicles are at any given time, while Serpent offers a complete ventilation system for successful tunnelling and mining operations, including system design, fan station, ducting and installation. Earlier this year, the two companies announced the deal, which will see ventilation requirements dictated by the presence of machines or equipment, the two companies told IM. “As Mobilaris MMI has the capability of creating geo fences and knows the position of equipment, a rule-based demand on the ventilation can be created when the machines enter the geo-fenced area,” they said. This provides a VoD solution that, not only considers geo fencing, but also data from air quality sensors. Combining the two methods ensures “a healthy work force environment, as well as keeping energy consumption under control”, the companies said. The integration of the Mobilaris Mining Intelligence and Epiroc Serpent Ventilation platforms will see ventilation requirements dictated by the presence of machines or equipment, the companies say