Improving Reliability of Mining Operations
Part 1: Are Mining Operators neglecting one of the most critical assets?
For mining operations, that rely on a connection to the electric grid for power supply, the transmission line used for this interconnection is one of the most critical assets that sometimes gets less attention than it deserves.
Many mine sites are remote and far away from the power grid and transmission lines from the mine to a substation in these remote area’s are often subjected to river erosion, floods, landslides, rock and snow avalanches, trees, debris flows, and many of these remote mines are at the end of a very long transmission line.
Mining operators depend on a reliable electrical source and the connected transmission line to power the site’s infrastructure including electrical draglines, power shovels, drills, conveyors, rock crushers, and concentrate grinders and electrical reliability is critical as even a brief interruption or power surge, say a millisecond outage through a transmission line contact with vegetation or component failure can cause various pieces of key systems to go offline which can take 40–60 minutes to get all of theses systems back in stable operations.
A longer unplanned outage, even a couple of hours due to storms, downed trees or equipment failure on the transmission line itself will have a major financial impact with the loss of production nevermind the needed 2–3 days to get all the sophisticated electrical components and integrated systems back up and running.
Many times, spare transmission line parts and components are not kept on-site and it may take days to source and delivered these to the site while production sits at a standstill.
Why is the inspection of transmission lines so important?
The cost of performing an inspection of the transmission line is relatively low compared to the cost of lost production, lost wages, repairs and equipment. For the bigger mining operators, a few days day’s loss in production can become a 7 figure loss in dollars and profitability and as such, the return on investment with having a yearly transmission line inspection can pay big dividends in the long run and more so for older lines within remote areas where limited access to the transmission line for inspections can be challenging using traditional inspection methods.
Another factor to consider these days is the risk of wildfires due to transmission line contact with vegetation and or component failure. Recently, several electric utilities have been held liable for wildfires that have been caused by transmission lines which they operate.
Many of these overhead power line wildfires started on remote lines that had not been inspected for many years and as a result, many utilities and power line operators are now being directed to enhance existing inspections programs and frequencies to mitigate wildfires in in high risk areas.
Why Use Drones for Transmission Line Inspections?
Drones are becoming more cost-efficient at capturing data from above. Many mines are now utilizing drones for stockpile measurements, surveys, tailings ponds inspection and asset management.
The inspection cost is one of the biggest considerations for using drones when compared to traditional foot and helicopter patrols depending on the types of inspections, work scope, accessibility and geography. Helicopters and their crews have a high hourly rate in the thousands of dollars per hour, which is most efficient for fast overhead patrols where hundreds of circuit miles need to be covered in a day. On the other hand, a drone and crew cost only thousands a day, which is more cost-efficient for conducting comprehensive detailed inspections and patrolling shorter lines for Veg. and detailed ROW inspections.
The trade-off with helicopter inspections is that you do not get all of the data or perspectives that a drone can offer flying within feet of the powerline. Also, most helicopter detailed inspections cannot provide data looking that a drone can safely access in tight spaces while providing the added benefit of data typically captured by foot patrols and or bucket trucks.
In a sense with a drone inspection, you get data from both the aerial and ground-up perspective resulting in a more thorough inspection and a better return on your inspection investment.
Part 2 of this story will cover our case studies on two power outages due to transmission line failure and our inspection outcomes.