Need for proppant

A Minnesota company creates a new start-up operation to meet frac sand demand.

In ancient times, sea water washed across Wisconsin and Minnesota, eventually leaving sand on the sea bottom that was uniformly hard and round. Eons later, the sand was discovered to be particularly desirable for use in horizontal hydraulic fracturing.

So the granular material is being gobbled up, carted away and injected into the ground again to prop open subterranean cracks so oil or gas can ooze out. Because this sand lies near the surface in Wisconsin, more than 100 proposed or operating mines have been organized to skim off the silicate material for fracking companies that can’t get enough of it.

Tiller Corp. entered this commercial fray two years ago. The 67-year-old Minnesota gravel and asphalt company based in Maple Grove was introduced to the business in 2010 when it began washing material for Preferred Sands LLC.

Tiller soon decided that the booming market for proppant sand perfectly complemented its core business, particularly in a stagnant road-building economy, so it started up Barton Industrial Sands LLC. The company located a surface mine near the St. Croix River in Wisconsin about 65 miles north of Minneapolis-St. Paul, Minn.

The mine is the former Soderbeck gravel pit near Grantsburg, a tract owned by Interstate Energy Partners. Below the gravel strata in the 160-acre property is a reserve of sand fine enough for use in fracking, as well as some coarser sands suitable for other commercial applications. Interstate signed up Barton to work the site.

“Interstate bought the property and contracted with us to take the sand from the ground, truck it, process it and load it into a railcar, and then it’s their sand again,” says Pete Olson, Tiller’s director of aggregate operations.

Material flow
At the mine, a Caterpillar loader dumps a raw mix of sand into a JCI 6 x 20 wet screen, which sends selected material along to a McLanahan separator. Separated-out material then enters a McLanahan flat-bottom classifier, which channels the slurry into a VD18 dewatering screen. The screen produces a stackable frac sand of 20 to 50 mesh size. The entire process takes five minutes.

Finer material that was de-selected is captured in a separate ultra-fine recovery process. This second filtering greatly reduces the volume of material that otherwise would end up in a slurry pond – thus enhancing the pond’s utility.

Four people run the entire operation, and a fifth is tasked with quality control. R.B. Scott Co. of Eau Claire supplied the equipment.

To process the sand, Barton executives settled on 20 acres located 25 miles south of Grantsburg in North Branch, Minn., at the southern terminus of the St. Croix Valley Railroad. The proximity to the railroad was a key consideration.

The shortline railroad operates on track formerly owned by Burlington Northern Santa Fe Railway and connects with BNSF main lines. This means Barton’s processed sand can be loaded at the plant for direct shipping south, east and west to America’s oil and gas fracking hot spots.

State of the art
Barton began to turn the nearly empty site into a state-of-the-art sand processing plant. The engineering firm M.A. Bielski & Associates, Chanhassen, Minn., designed a 90-ft.-high screening building, positioned the plant’s waste and storage silos, and sited three railroad track spurs for railcars.

The rest of the engineering – and all of the electrical wiring – was completed in house. Tiller employees were pulled as needed from its other divisions, including Todd Laubis, vice president of Tiller’s asphalt operations, who was instrumental in development of the industrial sand plant.

The thinking behind Barton’s approach to constructing a plant was that it had to be instantly recognized as a premier facility. “We were not going to be the first one in the business,” Olson says, “so we wanted to make sure we produced a very high-quality product in a very efficient operation.”

No one would argue with the plant’s efficiency, beginning with its receiving system. To truck the wet-in-process sand from Grantsburg, the company uses 25-ton grain haulers that were modified to handle the material. The trucks enter the plant grounds and roll onto a Masaba unloading hopper that can accommodate an entire truckload. According to Laubis, a truck’s approach triggers the equipment so that the sand is dumped into machinery prepared to receive it.

A Superior TeleStacker conveyor funnels the sand to a 100 x 100-ft. walled tent that can shelter 6,000 tons of the quartz material. A hopper in the floor of the tented area eventually feeds another TeleStacker, carrying the material to a 50-ft.-long, 9-ft.-high Custom Welding-Metal Fabricating Co. dryer attached to a Gencor burner. Temperatures reaching 220 degrees strip away any residual moisture still clinging to the sand from its washing at the mine.

From there the sand is bucketed to the upper reaches of a 90-ft.-high, steel-framed structure where the material is dropped through a series of Sweco screens to separate proppant sand from other products. Each finished and waste product is channeled into a separate Belgrade storage silo.

Waste products are accumulated in 220-ton silos and eventually trucked from the site. The finished product flows into 270-ton capacity silos from which it is conveyed on demand to a 100-ton trackside loading unit. From there, the sand is loaded into railcars in measurable dumps, with a scanner recording data on each car as it rolls up to be loaded.

24-hour turnaround
A remote-controlled Trackmobile moves the 110-ton railcars as needed, which is often. The sand doesn’t linger in North Branch. Laubis says that just 24 hours after a load of fracking sand is dumped into the Masaba hopper, the material typically has been dried, sorted out, loaded onto a railcar and sent on its way to a drilling field. Track spurs on the site can handle up to 70 railcars.

The whole process is managed in a 12 x 20-ft. control house designed by Barton Industrial Sands’ engineers. There, buttons and switches are passé. Instead, a controller moves a mouse and clicks on screens to monitor and regulate flow of the sand through the facility. Three Barton personnel work each day shift and three at night – plus quality control personnel. The economy of staffing is one reason the plant has attracted admiring industry visitors.

“There certainly has been a lot of interest in the facility from other producers,” Olson acknowledges, “and we’ve received good feedback from customers and from the railroad.”

The plant shipped its first carload of sand last year, and is geared to process up to 700,000 tons of high-quality proppant a year. An already-engineered second-phase expansion of the screening tower will double the plant’s production capacity as needed.

The processing facility incorporates seven baghouses, or emissions control devices, a reflection of public sensitivity about air quality. Mike Caron, Tiller’s director of land use affairs, said emissions from the dryer and dust from the stockpiled sand are even more closely monitored than emissions from gravel operations.

“There is a much higher review for an industrial-sand operation than we normally undergo,” Caron says. “In Minnesota, the standard for environmental review of an industrial-sand operation is a 20-acre site versus a sand-and-gravel operation, which is a 40-acre site.”

The stakes were raised at the North Branch facility because Barton Industrial Sands inadvertently started construction before actually receiving its permit for air quality. Consequently, the company had to do a review of its process and, with a consultant, find and implement the best available system for the facility. In other words, the plant also is state-of-the-art in its emissions controls.

Pond-less
The company suffered another momentary setback at the start of operations when sediment at its Grantsburg mine spilled into neighboring wetlands and from there into the St. Croix River. A new waste settling pond had been constructed from dirt on site, and the soil proved too porous to contain the sediment.

“Once we found out what was happening, we stopped operations at the mine immediately, in less than an hour,” Caron says. The settling pond was pumped dry and rebuilt using different material, but eventually it was decommissioned entirely, thereby eliminating the possibility of a recurrence. “We felt we could accomplish what we needed to do without a pond in that area.”

A study determined that no short-term or long-term environmental damage was incurred by the wetland or river. The site is now inspected daily and closely monitored. Legal challenges raised by the spill are still unresolved.

Olson calls the spill “a one-off. We are very regretful that it happened.” Tiller has been recognized over the years by local and state environmental organizations for its environmental awareness and precautions. But because of the mine’s connection to fracking, the incident got lots of media play.

“There definitely is a fear of the unknown,” Olson says, noting that the company received public pushback in applying for and constructing the dry processing plant in North Branch. “But since we have begun operating it, they have been surprised at how low an impact there is on the environment.”

Olson says the company is exploring other mine opportunities to add to its proppant sand reserve. The plant will stay busy regardless, because the operation is set up to process sand from multiple sources or as a custom supplier.

Take note
The processing facility incorporates seven baghouses, or emissions control devices, a reflection of public sensitivity about air quality.

Giles Lambertson in a previous life was a carpenter and has been writing about the construction, mining and heavy equipment industries for more than a decade. He can be reached at geepeela@yahoo.com.