The One Conveyor You Shouldn’t Use to Handle Frac Sand

Economists, analysts and American citizens are seeing a welcome resurgence in U.S. manufacturing in recent years, a phenomenon that some energy industry entities are connecting to hydraulic fracturing (or fracking). One of them is Energy In Depth (EID), an organization dedicated to communicating the benefits of responsibly developing America’s onshore energy resources – especially oil and natural gas extracted by fracking from shale and other abundant rock formations across the country.

In a January 2018 article, EID cites statistics from a research report that show how fracking has made affordable natural gas possible. Additionally, according to EID, U.S. shale gas production and the number of U.S. manufacturing jobs increased in tandem each year from 2010-2015, indicating a correlation between the two.

Many consider the combination of more jobs and less expensive energy to be highly desirable. Many others are justifiably concerned about the health, safety and environmental risks associated with fracking. One area of concern is the dust created by silica sand, an essential ingredient in the extraction of oil and natural gas from shale.

A 2013 study by the National Institute for Occupational Safety and Health (NIOSH) identified exposure to crystalline silica sand as one of the most significant known health hazards to workers during hydraulic fracturing. Breathing silica dust can cause several diseases including lung cancer and silicosis, a fatal and incurable respiratory condition that can take 10-15 years to demonstrate symptoms. Silica dust on clothing, vehicles and other personal items can transfer these health risks to workers’ homes and elsewhere throughout the communities where frac sand processing plants are located.

The conveying systems used in these plants are essential in the effort to significantly reduce if not eliminate silica-related health risks. It all starts by abandoning a traditional, budget-conscious approach to equipment selection.

Correct Conveyor Choice is Key
Belt conveyors typically are the most common material handling solutions found in sand and gravel applications. When evaluated strictly on a commercial basis, belt conveyors offer the least costly method of getting the job done. However, they come up short in one area that is critically important to the safe handling of silica sand: Enclosed conveying.

By nature, a belt conveyor will create carryover and spillage. It is not possible to enclose a belt conveyor without creating maintenance headaches due to material filling up the conveyor cavity and quickly damaging the belt. There is also no way to sufficiently prevent moisture or the elements from contaminating the product in a belt conveyor. But most importantly, belt conveyors cannot control hazardous silica dust as effectively as other conveying equipment:

  • En-masse or drag conveyors are the most suitable solutions for handling fine, highly abrasive silica sand. Low-speed, high-volume conveying over relatively long distances and sealed operation combine to minimize dusting and product degradation.
  • Screw conveyors can be used in some areas of a frac sand facility, but their use should be limited, as the tumbling and agitating method of transporting this abrasive material can lead to premature wear of the equipment’s housing, flighting and components.
  • Bucket elevators, typically the centrifugal type, are used for vertical applications and provide a dependable means of high-volume/high-lift material handling that is also enclosed.

Hydraulic fracturing has been a hot-button issue for years. Factions on both sides of the argument continue to debate the economic benefits of this energy extraction process versus the environmental and safety-related drawbacks. Two things are certain: Fracking initiatives won’t be slowing down anytime soon, and silica sand is required in the process.

Given the first certainty, the onus is on frac sand plants to handle the material as responsibly as possible to minimize the inherent hazards to their employees and the surrounding communities. A single lawsuit or worker’s compensation claim could cost a silica facility millions of dollars and quickly negate any up-front savings from choosing a belt conveyor instead of a material handling method that is better suited for the application. At CDM, we take the time to ask all pertinent application questions up front, and we make sure to take into account all industry-specific concerns before making a conveying equipment recommendation.