Rock Products is the aggregates industry's leading source for market analysis and technology solutions, delivering critical content focusing on aggregates-processing equipment; operational efficiencies; management best practices; comprehensive market
Issue link: https://rock.epubxp.com/i/88019
Sizing Product Efficiently A frac sand producer recently contacted Met Pro, of Bartow, Fla., about how they could size frac sand more efficiently. Their set up included a multi-deck vibrating screen whereby everything that passed through the bottom deck was trans- ferred to a classifying tank. The tank would classify the sand, but not sharply and with a lot of waste. The out- come was that a lot of sand was wasted and that the material that was to be dried contained a lot of fines (clay). This clay caused issues with the drier and was a major contributor to screen plugging. After reviewing the plant and visiting with the customer, a Met Pro Yield-Pro RCS70 rising current separator was suggested. The Yield-Pro was purchased and installed. The screen underflow was then pumped through a Met Pro Stack-Pro dewatering cyclone for thickening and primary de-clay purposes. The underflow of the Stack-Pro fed a Yield-Pro separator where rising current water and a teetered bed made the necessary cut point. The outcome was a clean, very near-sized product that the customer could feed to their dry plant. Waste was virtually eliminated and production increased. Minnesota Frac Sand Plant Proposal Stirs up Controversy A possible $70 million frac sand plant and rail depot is stirring up controversy in St. Charles, Minn. According to local news sources, a 300‐acre soy bean field outside of St. Charles could soon be the site of one of the largest frac sand pro‐ cessing plants in the country. Nick Koverman, city administrator of St. Charles, said the idea of a large frac sand processing plant has many concerned. "Not knowing the impact it will make, some of the immediate concerns are truck traffic, water table issues, noise, and dust," Koverman told KAAL TV. Minnesota Proppant says the proposed processing plant and rail depot would see around 50 trucks a day and would send one full rail cart up to North Dakota daily. "This is a state‐of‐the‐art plant and we have taken into consideration and have gone above and beyond what is neces‐ sary," the company said. The plant could create as many as 200 jobs with benefits, and farmers or land owners that sit on the sand could make 20 ROCKproducts • OCTOBER 2012 an estimated $200,000 to $800,000 per year for land rights. The disagreement on frac mining sites across Minnesota was highlighted by an environmental group that is calling for a moratorium on new sites. Environment Minnesota Research and Policy Center, along with neighbors of existing and pro‐ posed mining sites, gathered in Winona, Minn., to push a three‐year moratorium on future frac sand mining sites. The three‐year moratorium request, which will be sent to Gov. Mark Dayton with more than 400 signatures, is the lat‐ est attempt to slow the momentum of frac sand mining operations. "Frac sand mining has come just so quickly to this region that there's been, shockingly, little study of its impacts," said Samantha Chadwick with Environ‐ ment Minnesota Research and Policy Center. "So, what we want is time to un‐ derstand the risks and to figure out how to best protect communities in Min‐ nesota from the dangers, or if it should be allowed at all." Breaking into Frac Sand Producers moving into frac sand production are urged to follow these steps, according to ALMO En- gineering, a division of Allgaier- Group. n Identify initial scope of project. n Create concept. n Flow sheet/preliminary engineering. n Preliminary equipment list (based on preferred vendors and/or engineering company's experience). n Basic engineering. n Plant engineering. n Procurement of equipment. n Turn-key erection and build. n Commissioning. n De-bottlenecking. According to Alan Bennetts, senior process engineer for Weir Minerals, most frac sand plants follow the same formula. n Material is fed to a jaw crusher or in some cases, an impactor. n Material is screened to minus half-inch. n One of three wet gravity separation processes are used depending on the material to be produced: 1. Cyclones recovering material +140 mesh sent to dry screen. 2. +70-100 material produced using a hydrosizer and sent to a dry plant. 3. A one-product approach using wet gravity to make final product. n Material is dried using a fluid bed dryer, rotary dryer or other means and stored in silos prior to transport. n Frac sand plants face many of the same issues with regard to slurry management and dust control as other aggregates operations. Sources: Almo Engineering, www.almoprocess.com; Weir Minerals, www.weirminerals.com. www.rockproducts.com