Gold Mine Solves Carryback Issues Using Heavy-Duty Belt Cleaners
A global leader in conveyor technology has resolved excessive carryback problems on the conveyor systems of the largest gold mine in the Dominican Republic by installing several heavy duty belt cleaning systems. The Pueblo Viejo Dominicana Corporation (PVDC) -- newly updated and reopened by Barrick Gold Corporation -- realized the conveyor system’s existing belt cleaners were unable to adequately address the area’s overburden. Operators observed large amounts of carryback at discharge points, causing expensive equipment failures, unscheduled downtime and costly man-hours. Martin Engineering replaced the existing equipment with primary and secondary belt cleaners at sixteen discharge points, which increased production, reduced downtime and lowered the cost of operation.
“We lost nearly $250,000 in revenue due to clogged pulleys and headers from abrasive dust and belt fouling in the first year,” explained Ed Power, General Process Maintenance Superintendent at PVDC. “We decided to invite a team of experts from Martin Engineering to assess the problem.”
Production is 365 days a year, however between April and October the area can receive as much as 6 feet (183 CM) of precipitation. Moisture can cause cohesion in fine clay particulates, which reacts to load pressure, causing it to stick to the contact surface. According to Mike Lenart, Mechanical General Supervisor for PVDC, “The substance had the consistency of thick toothpaste, which was also able to adhere small chunks of aggregate to the belt, causing a destructive carryback that wreaked havoc on our pulleys and headers. It was a mess.”
In just two weeks, Martin Engineering replaced the existing belt scrapers with Martin QC1™ Cleaner XHD primary cleaners and DT2H™ secondary cleaners. These extra heavy-duty units are able to handle speeds of up to 1,200 FPM (6.09 MPS) on belts as wide as 96 inches (2.438 meters) and pulley diameters of more than 30 inches (762 mm). Installers fitted them with low-adhesion urethane blades specifically designed for sticky and tacky material. Able to withstand temperatures from -20° to 160°F (-30° to 70°C) with up to 12 inches (305 mm) of wear life, the blades endure high summer temperatures and constant production schedules with more time between replacements.
“The curved scraper is designed in sections, adjusted individually to conform to the belt, assuring continuous contact across the belt profile,” said Alfonso Granata, General Manager of PeGran, the local dealer and service agent for Martin Engineering products. “Martin Engineering manufactures a wide range of different cleaning blades, which specifically address the chemical make-up of almost all types of conveyed bulk materials.”
Sixteen Martin DT2H secondary belt cleaners accompanied the primary units to mitigate belt fouling. Attached two to three feet behind the header, the units were equipped with tungsten tipped urethane blades suited for heavy-duty applications. To avoid product loss due to fugitive material, the Martin Engineering team also installed 300 feet of ApronSeal™ Skirting constructed from 70 durometer EPDM rubber composite for its low abrasion index characteristics.
“We were also impressed by the warranty on the equipment,” said Power. “And to make sure we had the proper maintenance to comply with the terms, Martin Engineering trained a team to recognize potential problems throughout the entire conveyor system and either fix the issues or offer recommendations.”
Both PeGran employees and select PVDC employees were trained by Martin Engineering on its Walk the BeltTM program, which takes a holistic view of the entire conveyor system. “This ensures people both inside and outside of PVDC have the expertise necessary to achieve high operating standards, keeping the conveyor system running at maximum productivity, as well as recognizing potential hazards,” Granata pointed out. “We’re out there every two to three weeks doing inspections. We provide a detailed report on the state of the equipment and recommendations on how their trained internal team can safely perform maintenance.”
“Their focus on workplace safety was important to us,” Lenart added. “Even the equipment design has extra elements built in that help protect operators and maintenance staff.”
Operations are now more predictable and consistent, making executives and stakeholders more confident in the sustained operation of the mine, which is projected to yield a profit for the next 25 years.
“Ongoing follow up from Martin Engineering has been an important part of keeping the whole system running smoothly,” Power concluded. “They are just as committed to protecting our investment as we are, which means our conveyor carryback issues are all but gone.”