July 25, 2017
Water is the lifeblood of any aggregate operation, critical for the extraction of minerals, as well as liquid minerals and gases. While playing an integral role in the mining process, an overabundance of water can bring operations to a halt and create complex dewatering challenges for operations. Dewatering pumps, whether moving water from one location to another for reuse or removing water from a low-lying area, help maintain the smooth running of mine operations. As such, ensuring optimal pump performance and maximizing the life of dewatering pumps in aggregate operations should be top of mind for plant superintendents seeking to keep productivity flowing in the right direction.
To achieve this goal, mine operators are increasingly turning to preventive maintenance to keep pumps operating at their best, day in and day out, and in doing so, extending the lifetime of the pump. Many engage in a preventive maintenance agreement (PMA) — a service contract with equipment providers tailored to meet the mine’s specific needs — which includes regularly scheduled visits by service technicians to ensure equipment keeps running smoothly. A PMA enables mine operators to retain control over their maintenance budget while ensuring maximum equipment uptime at the lowest overall cost. Service technicians are fully equipped with the tools and parts required to carry out inspections and provide specialized support and on-site repairs. One such company to embrace this approach with positive results is Vista Sand, located in Granbury, Texas.
Increasing production expanded equipment needs
According to the U.S. Geological Survey, construction sand and gravel valued at $7.2 billion was produced by an estimated 4,100 companies and government agencies across the United States in 2015. The demand for ‘frac sand’ has jumped in the past several years as thousands of oil and natural gas wells are being stimulated using the hydraulic fracturing process. In fact, between 2009 and 2012, the amount of frac sand used by the oil and gas industry has tripled, creating a billion-dollar frac sand industry in a very short time.
Vista Sand specializes in dry silica sand for oil and gas fracturing. At its Granbury mine, the company excavates, washes, and dries silica sand for applications including hydraulic fracturing, building products, and cushion-sand, among others. This demands flexible, reliable, and robust dewatering equipment to keep operations running around the clock to meet growing market demand for sand solutions.
In 2014, an increase in production levels at the mine meant that additional dewatering solutions were required. The company was keen to take a proactive approach to ensure reliability and efficiency in dewatering operations. It approached Xylem to partner with them.
“A number of our mine managers had worked with Xylem previously, using its Godwin technology at various operations in Oregon and Montana, and so we were aware of the company’s mine water management expertise and broad portfolio of solutions,” says Nate Peterson, Vista Sand’s manager of geology and environmental.
Getting the right equipment
Achieving sustained high-performance of pumps in aggregate applications is dependent not only on the quality of the pumps and piping, but also on matching the equipment to the specific dewatering operation and ensuring an accurate configuration. The manufacturer completed an entire site review to fully understand the mine’s unique conditions and diverse applications. Water management requirements at the mine include pumps to dewater the pits, transportation of water within a vast multi-segmented pond system, and reclamation of process water for re-use in production.
Heavy rains, which are common in Texas, can result in considerable storm water that enters the pit and must be quickly removed. The combination of storm water and other naturally occurring seepage must be quickly cleared from the pit in order to minimize downtime and keep production moving. A range of dewatering equipment is required to meet these challenges and handle the harsh operating environment; reliability, efficiency, and durability are paramount.
The operation required a combination of large- and mid-sized pumps. Based on the site-wide review, a suite of rental dewatering equipment was proposed to tackle each application challenge cost-effectively. Initially, a selection of high-head fully automatic self-priming diesel pumps, as well as electric drive pumps, were provided. High-density polyethylene (HDPE) pipe was also supplied.
“We are focused on four key areas when it comes to selecting dewatering pumps: reliability, longevity of wear parts, ease of maintenance, and fuel consumption,” says Mike Fleet, Vista Sand general manager. Xylem proposed a rental model — enhanced by support from Mine Safety and Health Administration-certified technicians — that offered flexibility to handle dewatering tasks with a range of dewatering pumps and the associated equipment, while avoiding capital expenditure on expensive pumping equipment, which was not required by the mine on an ongoing basis.
Following the success of the initial application, the partnership grew to include the ongoing provision of advanced, often customized, dewatering solutions and service support.
Keeping operations running 24/7
Downtime as a result of pump breakdowns or damage to piping or other ancillary dewatering equipment is costly and challenging for mine operators. Reducing downtime and maximizing the efficiency of pumps is critical to supporting effective operations. At the Granbury mine, the partnership includes a PMA offering full-service maintenance and monitoring to mitigate against downtime.
Rental dewatering technologies can be offered with a full team for set-up and dismantling of pumping systems, and equipment is serviced on average every 10 days, with repairs completed as needed.
“Our objective is to stay one step ahead of potential equipment issues,” says Josh Jenkins, Vista Sand process engineering technician. “When selecting equipment, we look for an experienced partner who can provide a total solution and who will act as an extension of our team to get the job done.”
The preventive maintnance agreement provided peace of mind, he adds. Certified technicians service the rental pumps at the recommended 250-hour service internal and keep oil and fluid levels in check for optimal efficiency. The frequent servicing of pumps and HDPE pipe improves equipment reliability and supports the smooth running of operations at the mine, Jenkins says.
In addition to the dewatering equipment in use at the mine at a given time, a range of back-up equipment is often provided for more challenging applications which could result in costly downtime. This contingency planning approach means that, should a problem arise, pumps can be quickly replaced with a back-up solution to minimize downtime and keep operations running. In the event of a more significant emergency, a service team can be on-site within an hour, day or night.
Embracing maintenance to drive productivity
As mine operators seek to drive cost efficiencies and increase productivity, there is a growing need to ensure optimal performance of dewatering pumps. Aggregate managers across the globe are embracing PMAs as a means of delivering enhanced reliability in pumping operations and extending the lifespan of pumps. Recognizing that prevention is better than cure when it comes to pump maintenance is reaping benefits for those who embrace the approach.
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