Mining companies extract frac sand, also known as industrial sand or silica sand, by locating and mining sand deposits rich in silica suitable for hydraulic fracturing. Frac sand is a vital component in the oil and natural gas extraction industry, as it props open underground fissures created during extraction, facilitating the release of hydrocarbons from shale rock formations.
Frac sand is a derivative of deposits of high-purity quartz sandstone containing well-sorted, round, or angular, and durable sand grains. These properties are essential for ensuring the sand’s effectiveness in hydraulic fracturing.
Sand Mining
Identifying suitable locations for frac sand mining involves combining geological assessments, exploration, and regulatory considerations to be cost-effective and environmentally sound.
Sand demand is high, as each well necessitates as much as 10,000 tons of sand. The U.S. shale industry consumed an estimated 112 million tons of proppant in 2022. [AOGR.com] As the industry increasingly seeks finer sand, the demand is becoming more concentrated in select locations capable of providing high-purity silica sand grains.
Frac sand mining primarily occurs in regions abundant in high-quality sand deposits, often near active oil and gas extraction sites. Transportation costs can significantly impact frac sand operations’ overall economics and efficiency. As a result, many frac sand companies are increasingly focused on locating sand deposits in proximity to hydraulic fracturing operations.
The Midwest, particularly states like Wisconsin, Minnesota, Illinois, and Iowa, has served as a significant hub for frac sand mining due to its extensive, accessible deposits of high-quality silica sand. Wisconsin has witnessed substantial frac sand mining activity. In 2017, Wisconsin’s 44 active mines accounted for almost half the nation’s installed frac sand capacity, but this has changed as local frac sand mining is replacing older fixed base mines. In fact, a significant amount of total sand proppant demand is now locally sourced.
Texas, a major oil and gas production hub encompassing the Permian Basin and Eagle Ford Shale, has also experienced substantial frac sand mining operations. Texas hosts in-basin frac sand mining operations and transportation infrastructure to supply sand to neighboring regions.
While frac sand mining occurs in other states with suitable deposits, such as Oklahoma, Arkansas, Ohio, Michigan, and Nebraska, its extent remains lower compared to the Midwest and Texas.
The Role of Environmental Professionals and Technology
Environmental consultants and geologists play crucial roles in frac sand development by providing expertise and conducting assessments to ensure that mining operations are conducted responsibly and in compliance with environmental regulations. Full-service environmental firms can often identify strategies to save money on these projects with their deep bench of professionals.
The exploration geologist is interested in several elements:
Geological surveys and assessments constitute essential steps in identifying potential areas harboring sand deposits meeting frac sand specifications. Geologists examine the region’s geological history, sedimentary layers, and rock formations to gauge the likelihood of encountering high-quality sand.
Modern technology employs satellite imagery and remote sensing techniques to pinpoint areas displaying characteristics linked to frac sand deposits. These techniques aid geologists in singling out locations warranting further exploration.
Geological surveys become particularly crucial in regions where sand deposits may be beneath layers of overburden material. Geological assessments become indispensable where hidden sand reserves are beneath soil, sediment, or rock layers. These assessments involve a comprehensive study of the subsurface geology, often necessitating various exploration techniques and technologies.
Upon identifying a prospect area, core sampling initiates. Geologists evaluate these samples to assess the sand’s quality and suitability for hydraulic fracturing. Core sampling aids in determining the sand’s grain size, roundness, angularity, and sphericity.
Laboratory testing on core samples appraises the sand’s physical and chemical properties. This testing encompasses establishing the sand’s silica content, grain size distribution, crush resistance, and other pertinent characteristics. The American Petroleum Institute provides a standard for measurement of proppants in hydraulic fracturing (API STD 19C, 2020).
Particle Attributes and Types for Effectiveness
The size and configuration of frac sand particles play a pivotal role in assessing their effectiveness within the oil and gas industry. These characteristics can influence the flow dynamics of the frac fluid and the pressure capacity achievable at the frac site. Moreover, particle size and shape variations can impact the reservoir’s material retention capacity and the rate at which the frac fluid can be introduced and retrieved. These aspects substantially influence the efficiency of the hydraulic fracturing process and, consequently, the overall outcome of the operation.
Round frac sand particles are the preferred choice due to their well-sorted and consistently uniform size. These spherical particles are exceptionally suited for creating fracture pathways, as they can effectively occupy any voids within the formation that may result from the hydraulic fracturing process.
The most used frac sand comprises round, well-sorted particles with a median grain size typically falling within the 0.6 to 0.8 millimeters (mm) range, also known as a “20/40 mesh” for the sieve size range. This type of frac sand is often referred to as “Northern White” sand and has historically been a preferred choice for hydraulic fracturing due to its uniformity and roundness. However, many companies are going to finer sands of 100 to 200 mesh. Common frac sand sizes include 40/70, 30/50, 20/40, 100 mesh, 200 mesh, and finer.
Alternatively, crushed or angular frac sand particles find common usage. These particles exhibit irregular shapes and tend to be larger than their round counterparts.
These particles’ irregular shape and larger size can enhance their ability to remain suspended in the frac fluid, meaning they are less likely to settle out of the fluid and can effectively transport downhole. Crushed or angular particles can be less prone to embedment in the formation under high pressure, which means they may be less likely to get stuck in the fractures and can help maintain fracture conductivity. Also, the irregular shape of these particles can create a more tortuous flow path in the fractures, which can help control fluid flow and prevent the formation of large voids.
Various other types of frac sand particles are also accessible, including sieved frac sand tailored to specific size requirements. Such sand is employed when a particular particle size is mandated, such as in formations with precise pore size constraints.
Resin-coated sands, also known as resin-coated proppants (RCP), are used in hydraulic fracturing to enhance the performance and longevity of proppants in the well. Resin-coated sands are chosen based on their compatibility with the reservoir conditions and the desired proppant behavior.
The choice between round and crushed/angular frac sand particles depends on the specific reservoir characteristics, well conditions, and production goals. Several types of proppants may be preferable for different scenarios, and selecting proppants is a critical consideration in optimizing hydraulic fracturing operations. As a result, there is ongoing research and experimentation in the industry to determine the most suitable proppant for various frac applications.
The typical compressive strength of frac sand can vary depending on factors such as the source of the sand, the processing methods used, and the application’s specific requirements. However, frac sand generally has a compressive strength ranging from approximately 6,000 pounds per square inch (psi) to 14,000 psi. This range gives the sand the necessary mechanical strength to withstand the pressures and stresses associated with hydraulic fracturing operations.
Due Diligence for Sustainability
Before committing to a prospect, mining companies routinely undergo comprehensive due diligence, factoring in technical, regulatory, and economic considerations. This process aids in assessing the suitability of the location for frac sand mining.
Assessing the economic viability of a prospective frac sand mining site remains paramount; this entails estimating mining, processing, transportation, regulatory compliance, and market demand and pricing costs.
The location’s accessibility also bears practical significance. Closeness to transportation infrastructure (roads, railroads, ports) and water sources significantly impacts mining operation feasibility.
Identifying suitable locations also necessitates addressing local, state, and federal regulations.
Robust environmental impact assessments often become prerequisites to evaluate potential mining activity environmental repercussions.
Oil and gas drilling activity levels drive frac sand demand. During heightened drilling and hydraulic fracturing, frac sand demand typically escalates, potentially leading to higher prices. Frac sand extraction methods encompass surface and underground mining, with surface mining primarily involving open-pit or quarry operations being the most common approach.
Following extraction, the sand undergoes a sequence of processing steps to meet the necessary extraction specifications. Processing includes washing, sieving, and, sometimes, further chemical treatment to eliminate impurities and guarantee that sand compliance is within required standards. Processing is another opportunity for your environmental professional to advise on minimizing groundwater contamination risk.
Once processed, frac sand goes to well sites via trucks, railroads, or conveyor belts. The sand is typically delivered in bulk and stored at the well site until needed.
Innovations
An innovative approach to frac sand development is wet sand processing. Producing frac sand involves a washing step to remove impurities. Historically, it has also required a drying process to facilitate transportation and on-site metering, which comes with associated emissions. However, using wet sand eliminates the need for drying, thereby eliminating emissions related to that drying process. When combined with the practice of utilizing “proximity” wet sand mines in a multimodal delivery approach, the emissions savings from reduced trucking distances more than double. Collectively, these technologies reduce operational emissions in the last mile by an average of ninety percent.
This environmentally friendly approach enhances safety, efficiency, and cost savings. Combining eliminating the drying process and reducing miles leads to a reduced operational footprint. This reduction per well is equivalent to removing eighty-five passenger cars from the road yearly or eliminating 975,000 vehicle miles driven each year. [AOGR.com] In-field mining and logistics reduce emissions at the sand mine and during transport from the mine to the well.
The use of wet sand also provides an effective solution to protect employees from silica dust exposure, both at the mining site and during fracking operations.
The Pros and Cons
The demand for frac sand can be cyclical, influenced by oil and gas prices and drilling activity levels. Market dynamics may trigger frac sand price fluctuations and impact mining operation profitability.
The frac sand industry has consolidated, with larger companies acquiring smaller ones. This consolidation can yield positive and negative outcomes, including enhanced efficiency and potential reductions in competition.
It is essential to recognize that the positive facets of frac sand mining counterbalance with potential negative environmental and social effects.
Positive Impacts:
Negative Impacts:
Regulatory Requirements and Environmental Assessments
Both environmental consultants, engineers, and geologists assist in navigating complex regulatory requirements related to frac sand mining. Environmental consultants play a crucial role in supporting frac sand development by providing expertise and conducting assessments to ensure that mining operations are conducted responsibly and in compliance with environmental regulations and that environmental techniques, strategies, and technology are employed to make the work as cost-effective as possible.
Environmental consultants conduct environmental assessments to assess the potential environmental impacts of frac sand mining operations.
Drawing a Line in the Sand
Frac sand development encompasses identifying, extracting, processing, and delivering high-quality sand to support frac operations within the oil and gas industry. Demand for frac sand is substantial, with each well requiring as much as 10,000 tons. This demand has led to a concentration of production in locations capable of providing high-purity silica sand grains, particularly as the industry seeks finer sand. Over the past five years, the frac sand supply chain revolution has been one of the most innovative subsectors in the unconventional oil and gas space.
This process requires a careful balance of environmental, regulatory, and economic considerations to ensure this essential resource’s responsible and sustainable supply. Ongoing research and innovation to meet evolving industry demands and optimize the efficiency and effectiveness of hydraulic fracturing operations while minimizing environmental impacts continues. Furthermore, collaboration among mining companies, environmental consultants, geologists, and regulatory authorities is key to the responsible development of frac sand resources that benefit the industry and the environment.
About the Author: David Palmerton, Jr., PG, is a Project Director for the Environmental Services Practice. Mr. Palmerton has managed strategic and technical environmental consulting issues for Fortune 100 companies throughout the United States. He has typically provided senior technical oversight, strategic support, and cost control for large multi-component environmental sites. His consulting assignments have included environmental science-based investigations, including soil, sediment, groundwater, and dense non-aqueous phase (DNAPL) investigations and remediation at some of the nation’s most high-profile sites. Mr. Palmerton has over 35 years of experience in environmental consulting in the areas of environmental liability assessment, investigation and remediation. Reach Dave at or on LinkedIn.
The updates to air regulations intend to remove redundant requirements and reduce compliance burdens where environmentally appropriate.
The U.S. Environmental Protection Agency (EPA) proposed updates to the oil and natural gas industry national standards. The proposal intends to remove regulatory duplication while maintaining health and environmental regulations on oil and gas sources that the agency considers appropriate. The proposal is the result of EPA’s review of the 2016 New Source Performance Standards (NSPS) for the oil and natural gas (O&G) industry conducted in response to Executive Order 13783 – Promoting Energy Independence and Economic Growth. The goal was to review existing regulations that could potentially “burden the development or use of domestically produced energy resources,” including oil and natural gas.
The resulting regulatory impact analysis from EPA estimates that the proposed amendments could save the O&G industry $17-$19 million a year, for a total of $97-$123 million from 2019 through 2025.
“EPA’s proposal delivers on President Trump’s executive order and removes unnecessary and duplicative regulatory burdens from the oil and gas industry,” said EPA Administrator Andrew Wheeler. “The Trump Administration recognizes that methane is valuable, and the industry has an incentive to minimize leaks and maximize its use. Since 1990, natural gas production in the United States has almost doubled while methane emissions across the natural gas industry have fallen by nearly 15%. Our regulations should not stifle this innovation and progress.”
In its primary proposal, the agency is proposing to remove sources in the transmission and storage segment of the O&G industry from regulation. These sources include transmission compressor stations, pneumatic controllers, and underground storage vessels. The agency is proposing that the addition of these sources to the 2016 rule was not appropriate, noting that the agency did not make a separate finding to determine that the emissions from the transmission and storage segment of the industry cause or significantly contribute to air pollution that may endanger public health or welfare.
The primary proposal also would rescind emissions limits for methane, from the production and processing segments of the industry; keeping emissions limits for ozone-forming volatile organic compounds (VOCs). These sources include well completions, pneumatic pumps, pneumatic controllers, gathering and boosting compressors, natural gas processing plants and storage tanks. The controls to reduce VOCs emissions also reduce methane at the same time, so separate methane limitations for that segment of the industry are redundant.
In an alternative proposal, EPA would rescind the methane emissions limitations without removing from regulation any sources from the transmission and storage segment of the industry.
The agency also is seeking comment on alternative interpretations of EPA’s legal authority to regulate pollutants under section 111(b)(1)(A) of the Clean Air Act.
This proposal is in addition to a September 2018 technical action that proposed targeted improvements to help streamline implementation, reduce duplication of EPA and state requirements, and significantly decrease unnecessary burdens on domestic energy producers. EPA is currently reviewing comments received on that technical package and expects to issue a final rule in the upcoming months.
EPA will take comment on the proposal for 60 days after its publication in the Federal Register, and will hold a public hearing. EPA will announce details of the hearing shortly.
More information, including a pre-publication version of the Federal Register notice and a fact sheet, is available at https://www.epa.gov/controlling-air-pollution-oil-and-natural-gas-industry
Link to the proposal: https://www.epa.gov/sites/production/files/2019-08/documents/frn_oil_and_gas_review_2060-at90_nprm_20190828revised_d.pdf
Link to fact sheet:
Air Monitoring at SCS Engineers / O&G Services
