The Best Locations in the US for Finding Frac Sand

The Best Locations in the US for Finding Frac SandThere is no question that fracking has become the new standard for getting the most out of an oil or natural gas well. Two and a half years ago, 95 percent of wells were being fracked, and a total of about 82,000 such wells were operational in September 2013. With fracking occurring in 17 different states, the need has also multiplied for appropriate proppants, such as frac sand, to prop open those shale fractures deep underground. Fortunately, there are a number of locations around the US where frac sand is being mined and processed for use in the hydraulic fracturing of fossil fuel wells.

The Characteristics of the Best Frac Sand

The best frac sand has a number of very specific properties which make it more difficult to obtain than just taking a front loader and dump truck to the nearest beach. Frac sand must be very strong in order to withstand the pressure of gravity when the pressure of the fracking liquid is removed from the well. The sand grains must be of uniform size and round shape in order to flow easily into the shale seams when they are cracked open, without linking together and preventing the oil and natural gas from escaping into the main wellbore for extraction. The frac sand grains must also be light enough to be transported within the fracking liquid, and impervious enough not to disintegrate when immersed in that fluid.

The Locations of the Best Frac Sand

Fortunately for US fracking interests, there are a number of states with high quality frac sand in the US.

Wisconsin and Minnesota

Arguably the best frac sand in the US is found within bluffs of silica sandstone in the Upper Midwest that were once the sandy floor of an ancient ocean bed. 500 million years ago, the tidal flows slowly wore down these grains of silica, shaping them into uniform, strong, round, nearly perfect frac sand. That sea bed is now known as the St. Peter Sandstone, and, in Wisconsin alone, there were 115 frac sand mines and plants spread along the western and southern portions of the state in October 2013. In the southeastern portion of neighboring Minnesota, frac sand from the St. Peter and similar formations is being mined in nine different locations.

The frac sand mine owners in these states are quite different, however, perhaps because of the number of mines involved. In Minnesota, the mine owners are local companies, while in Wisconsin, major players from out of state have purchased multiple mines and processing sites. Superior Silica Sands, for example, is headquartered in Fort Worth, Texas, but owns plants in Clinton and New Auburn. Hi-Crush Partners of Houston, Texas, operates mines in Wyeville and Augusta, and is proceeding with plans to open a third mine location along the border between the towns of Whitehall and Independence. Houston’s EOG, which is primarily a drilling company, works a number of frac sand mining locations in Wisconsin, as well as a central processing plant. Wisconsin Industrial Sand, a subsidiary of Fairmount Minerals, owns three frac sand mining sites in the state.


The St. Peter sandstone belt extends into Illinois where, at the LaSalle anticline, the stone has been uplifted by geological forces, making it accessible to open pit mining. Sand has been mined in this area for 150 years for a variety of industrial uses. US Silica is active in this area—and in fact owns one of those historic sand mines—as is Missouri-based Mississippi Sand. Unimin, which is the largest quartz proppant producer in the world, has 44 mining and processing facilities in North America, including Illinois. With five mines in operation and three more proposed in 2013, frac sand mining is on the move in Illinois.


While Michigan ranks third in the US for industrial sand production, the frac sand boom has not been as prevalent in this area. Along the Great Lakes there are a large number of sand dunes, but these do not always contain frac sand quality granules. None of the major frac sand producers are listed amongst the eleven active sand dune mining sites, although a subsidiary of Fairmount Minerals, Technisand, owns three active sites.


Good quality frac sand is not limited to the Midwestern US. Another major source of sand is found in Texas, where the Hickory Sandstone Formation has been mined for decades by Texas Silica. Two types of sand are mined by this company. The first type, Fredonia, is comparable to much of the Midwestern frac sand. The sand grains of the second, Brady, are not as strong as the Midwestern quartz, but they are suitable for fracking situations which require slate closure pressures of less than 4500 pounds per square inch.

Both types of sand are also naturally much less expensive to transport to nearby drilling sites in the south and western US. Another major player in Texas is Fairmount Minerals, although their main presence in Texas is in the transportation business, with over a dozen terminals scattered across the state.

Activity in Other States

The hunger for frac sand has led most states to take a good look at their geological formations to ascertain whether they can join the fracking boom. Frac sand is being mined from Virginia to California, North Dakota to Florida. In fact, only 15 of the lower 48 US states have no frac sand activity. However, whenever possible, thoughtful mining companies are likely to choose established and proven frac sand grains for their fracking operations.

Will Natural Gas Help Save Our Water Supply?

Will Natural Gas Save Our Water SupplyFracking, or the hydraulic fracturing of shale deposits far underground to release their store of natural gas, uses an average of 4.4 million gallons of water-based fracking liquid per well, injected at high pressure, to break open that shale. Thus fracking is frequently considered one culprit (among many) in the ongoing water wars in the Western US. In fact, there’s an unspoken assumption in many Western states that there simply isn’t enough water to go around. Fortunately, activists aren’t the only ones taking a good hard look at water usage. Recently some researchers reported that significant water savings is occurring in a very unlikely place: how we use that natural gas to generate our electricity.

The Role of Water in Traditional Power Plants

Traditionally, coal-powered plants generate electricity by burning coal to heat water to the boiling point. Once the water turns to steam, it travels under pressure to a turbine, where the directional pressure of the steam flow turns the turbine blades. The shaft of the turbine is connected to a generator. This has magnets within wire coils which, when spun, produce electricity. This process means that significant amounts of water are used in every coal-powered plant in the country.

Water is also the most commonly used cooling method to return that steam to its liquid state for a return trip through the power plant. In fact, many traditional power plants, especially in the Eastern US, use “once-through” systems for cooling. At these plants, water is taken from nearby rivers, lakes or oceans, used to cool steam back to water, and then discharged into the source from which it came. This is no longer the preferred method, however, because of the disruption to the local ecosystem by the removal of large quantities of water, and thermal pollution—returning that water to the ecosystem a lot hotter than it left.

Wet-recirculating cooling towers expose that “cooling” water to the ambient air to assist in the cooling process. This results in the loss of some of the water through evaporation. While the process may need less water for each cycle of cooling, more water is lost to evaporation, resulting in a net higher water consumption. Unfortunately for drought-stricken Western states, this is the most commonly-used process in the Western US.

The Role of Water in Newer Power Plants

Fortunately, technology is continuing to improve the design of power plants. Some newer power plants are generating electricity using a natural gas combined cycle, or NGCC, process. These power plants use only one third the water of traditional steam turbine plants.

There are also a few power plants that use only the ambient air for cooling, decreasing water consumption by over 90 percent. The combustion turbine process brings in ambient air, compresses it, then heats it. Air naturally expands when heated, and that expansion is used to turn the turbine blades. The hot air is then released and fresh air is brought in from outside to be heated in the next cycle of the process.

Good News for Our Water Supply

These newer types of natural gas-powered plants use much less water, and what researchers are discovering is that the water saved is actually much greater than the amount of water needed for the fracking process. A study conducted in Texas has given us the first concrete numbers in this regard, and they are very encouraging.

Texas generates more electricity than any other single state in the US, which made it an excellent place to measure the effects of these changing technologies. This study collected water use data from every power plant in the state—423 of them. They studied all of the types of power plants mentioned above, as well as a “peaking” type of power plant that works in tandem with wind energy to provide peak power when demand rises above the capacity of the wind farm to handle.

What these researchers discovered was that for every gallon of water used in fracking, 33 gallons of water were being saved through the generation of electricity with natural gas power plants instead of coal. This means that shifting from the old, steam turbine technology to natural gas powered plants creates a net water savings that, in 2011, could have supplied 870,000 Texas residents with all the water an average user would need for the year.

This study concluded that, far from exacerbating drought with its use of water, fracking is actually making the entire electric power system more resistant to drought. Furthermore, the basic facts in this study should hold true in other states since the shift to natural gas power plants is occurring around the country.

The study also documented that fracking actually accounts for less than one percent of water usage in Texas. The results of this study should lessen fears for our water supply, but they also illustrate the importance of continued research to understand the unheralded benefits of technological innovation. As this research shows, fracking is a relatively new technology and its benefits are still being discovered.

What Exactly is Marcellus Shale and Why does it Matter?

What Exactly Is Marcellus ShaleIn the ongoing drive for the US to become energy independent, the hydraulic fracturing, or fracking, of shale has become a major source of additional US oil and natural gas. As American geologists continue to explore the mineral riches hidden—sometimes, ironically, within plain sight—within the stones of our continent, they are discovering that the Marcellus Shale formation could become a “super giant” natural gas field and major contributor to decreasing our dependence on foreign fossil fuels.

What Exactly is Marcellus Shale?

The Marcellus Formation is a large bed of sedimentary black shale located in the eastern part of North America. Primarily located in New York, Pennsylvania, Ohio and almost all of West Virginia, it is named after a distinctive outcrop of the shale located near Marcellus, New York. This shale is so black that it resembles coal; in fact, in the early 1800s, it was frequently mined in the areas where it was close to the surface, because people mistakenly thought that its presence hinted at nearby coal seams.

Marcellus Shale is both low in density and rich in organic matter. It was originally laid down as layers of fine mud in the deep water of an ancient sea. The shale itself is not very permeable, meaning that the natural gas elements embedded within it have remained there over the almost-400 million years since the deposit was formed. However, the shale flakes easily along the stratigraphic layers of ancient mud, making it a perfect candidate for fracking.

Today this shale is mostly located a mile or more beneath the surface of the earth, which also makes it an expensive candidate for drilling. However, there are places on the north end of the formation, such as Marcellus, New York, where it appears in outcrops where two joint planes of the formation, which run at almost 90 degree angles, form smooth, sheer cliffs.

Why is Marcellus Shale Important?

Today we recognize that the value of Marcellus Shale may far exceed that of the coal our ancestors were searching for. Power companies are increasingly turning away from coal and toward natural gas to fuel electrical power plants. Not only are the newer natural gas plants more efficient, since the heat and exhaust generated by the natural gas can be recycled for additional power, they produce only half of the greenhouse gases emitted by coal-fired power plants. This makes it much easier for power companies to comply with the US Climate Action Plan, which seeks to reduce greenhouse gas emissions by 17 percent from 2005 levels in the next 6 years.

In 2008, it was estimated that 500 trillion cubic feet of natural gas might be trapped within the Marcellus Shale, and that ten percent of it might be recoverable through fracking technology. This estimate made it the largest single natural gas deposit in the US. Today, that recoverable number has been increased to 141 trillion cubic feet. Currently an area of approximately 104,000 square miles across four states is being explored or tapped.

The location of the Marcellus Formation is also important in the geography of the US. Marcellus Shale is relatively close to significant population centers in New England and the Mid-Atlantic states. This means that transport costs for conveying the natural gas from wellhead to power plant will be significantly less than for natural gas mined in North Dakota or Texas.

Tapping Marcellus Shale

The natural gas trapped in the Marcellus Formation has been mined for many years, but with unpredictable results due to the presence of pockets of natural gas. The first company to draw significant quantities of natural gas from Marcellus Shale was Range Resources – Appalachia LLC. Drilling in Washington County, Pennsylvania in 2003, they were able to tap a significant flow of natural gas—and then expanded upon it by experimenting with the new horizontal drilling and hydraulic fracturing that was being used with the Barnett Shale formation in Texas.

The very friability of the Marcellus Shale creates fracture pockets where natural gas naturally collects. Therefore, if companies can tap an area where significant underground fracturing has occurred in the past, they will be able to tap into a richer pool of existing natural gas, with less need for hydraulic fracturing to create that web of gas-holding pockets. Drilling vertically down to the Marcellus Shale bed, then horizontally along it, and fracking along the horizontal portion, will yield maximum natural gas in return for the effort and expenditure.

Further geologic study has determined that the best places to tap that hundred-thousand square miles of Marcellus Shale is where the formation is thickest, and therefore holds the most net organic-rich shale. The Marcellus Formation is now being mapped to determine where those thickest intervals are located.

Marcellus Shale presents a “super giant” opportunity for the US to become less dependent on foreign sources of fossil fuels and to perfect the hydraulic fracturing technology which has made its riches accessible.

An Overview of the Natural Gas Pipeline Network

An Overview of the Natural Gas Pipeline NetworkDo you take hot water for granted? Have you ever considered the mechanics involved in safely transporting the natural gas that heats that water—from where it is pulled from the ground, to a processing plant, and then to your home? The volatility of natural gas means that it must be completely contained during the entire transport process. In the same way that, two centuries ago, telegraph wires were installed across the country (usually along railway lines), and telephone lines followed a century later, the US is home to a planned natural gas pipeline network of immense scope, strength and complexity. Much more than a simple series of interconnected pipes, this well-developed network delivers natural gas to just about any location in the country.

A Summary of the Natural Gas Pipeline Network

Natural gas was first used to light city streets in Baltimore in 1816, and the first city-owned gas distribution company was set up in Philadelphia in 1836. The majority of today’s natural gas pipeline network can be traced back to the 1930s and 1940s. Today, there are more than 305,000 miles of natural gas pipelines spread across the US. These are divided into 210 different—but interconnected—systems. The natural gas moves through these pipelines with the aid of 1,400 compressor stations to more than 11,000 delivery points across the US. There are 400 underground storage facilities where natural gas is warehoused, and 49 places where it enters or exits the US system, either to our neighbor countries of Canada and Mexico, or overseas.

LNG, or Liquefied Natural Gas, is also transported through this system. LNG is natural gas that has been cooled to temperatures below minus 259 degrees Fahrenheit (or minus 161 degrees Celsius), which transforms the gas into its liquid state. In this form, it is much more economical to transport, since its liquid form takes up 1/600th the space of natural gas. Most LNG comes from less than a dozen overseas countries, and the US pipeline network includes 8 LNG import facilities and 100 peaking facilities, which is where the LNG is converted back into a gas.

Transportation through the Pipeline Systems

Those 210 pipeline systems mean that natural gas is transferred into the custody of a variety of entities on its trip from the wellhead to your home. The process begins with small “gathering lines” which move the gas from the individual drilling sites to a processing plant where impurities are removed. After processing, the gas is moved through large-diameter main lines to market hubs or storage facilities. These storage facilities are underground and usually were once oil and gas reservoirs, aquifers, or salt caverns. When the gas is needed, it is transported through a grid of pipes to your city or town, and eventually to your home.

Pipeline Network Capacity and Utilization

Each natural gas pipeline is constructed and rated at a certain certified capacity, and it is most efficient to operate as close to 100 percent capacity as possible. This is not always feasible, however, especially during summer months when demand is lower. Summer is therefore the most frequent time when portions of the system are taken offline for scheduled maintenance. On the other hand, the official capacity may also be exceeded, within certain limits, during peak utilization periods—usually during winter months. This means that, when excess capacity is needed, gas compression levels are increased in order to maximize the amount of gas being transported.

These seasonal variances are more likely to occur on the more localized, grid system portions of the network, as opposed to the “trunklines” which carry the gas long distances. The underground storage facilities located throughout the system accommodate the ebb and flow of demand. Custodians may also choose to hold natural gas in storage in response to price fluctuations, or to stockpile natural gas during the summer in anticipation of the onset of winter’s cold. This means that the peak amount of gas within the entire system usually occurs around November 1.

Pipeline Design and Development

Those peak utilization periods drive the ongoing design and development of the natural gas pipeline network. Design parameters for both pipelines and integrated storage facilities must balance the needs of production, transport, and delivery variables. The goal is to transport the natural gas in the most efficient manner for the most reasonable cost, while also planning ahead for future expansion needs.

The diameter of the pipe and its rated carrying pressure are two critical components in the design process. In order to keep pressure more constant throughout the line, in areas in need of additional capacity (usually in the form of reduced pressure when passing through populated areas), the standard procedure has been to maintain nominal pipe diameter, but increase the thickness of the pipe walls.

Natural gas demand is expected to rise by an average of 0.8 percent per year for at least the next 20 years, which means that the demands on the US pipeline network will also continue to grow. While residential use may actually fall in the next 20 years, due to the increased efficiency of household appliances, additional needs in the industrial and electric power sectors should mean that the natural gas pipeline network will continue to form an integral part of the US energy grid.

The Frac Sand Industry’s Commitment to Minimizing the Environmental Impact of its Work

The Frac Sand Industrys Commitment to the EnvironmentWith the exception of old black-and-white photography, nothing is truly black and white. Just about everything is more complex, nuanced and more layered than it first appears. This is certainly true when it comes to drilling for oil and natural gas. Initially, fracking was seen as an improvement to the industry’s drilling process, because it made each well much more efficient, and this has allowed natural gas to supplant dirtier coal in fueling power plants. But soon people began to express concerns about whether the liquids used in the fracking process were affecting water quality. Now studies are showing that the fracking liquid is too dense to migrate the significant distance (usually several thousand feet) between shale deposits and aquifers. Newer drilling practices are also recycling up to 90 percent of the extractable fracking liquids for additional fracking procedures, significantly limiting the amount of fracking liquid that is available to contaminate surface water or nearby land.

In the same way, the use of strong, uniformly-shaped grains of sand as “proppants” in the fracking process was initially hailed as an industry breakthrough, but not long after, concerns began to raise about the possibility of airborne dust particles being released during frac sand mining and processing. Like the fossil fuel drilling industry in which it plays an integral part, the frac sand industry understands this skepticism, and recognizes the need for safety and environmental stewardship, and is embracing the important steps necessary to maximize safety, and minimize the environmental impact of mining, processing, and transporting frac sand.

Mining Frac Sand

When it comes to mining frac sand, the biggest issue for both mine workers and nearby residents is “fugitive dust,” which is raised during the process of mining the sand. Mining companies are required to have processes in place for controlling fugitive dust in states like Wisconsin, where 75 percent of the frac sand is currently being mined. This means more than controlling dust during the blasting process; it also covers dust that might blow off of conveyer belts, trucks or piles of sand.

Minnesota’s Department of Health recently established a guideline for particulate exposure of no higher than 3 micrograms per cubic meter of particulates that measure 4 or less micrometers in diameter. This diameter, called the PM4 for short, is the size that worries health experts, measuring less than one-tenth the diameter of a human hair.

Frac sand companies like EOG Resources are funding their own studies to ensure safety for their workers and those who live nearby. EOG Resources is monitoring PM4 type emissions at four Wisconsin facilities, and has found the air to contain “much lower concentrations” than Minnesota’s established guideline, according to Wisconsin’s Department of Natural Resources (WDNR). In Minnesota, frac sand mining companies are committed to the environmental review process and willing to spend the millions of dollars necessary to adhere to state regulations, according to Dennis Egan of the Minnesota Industrial Sand Council.

Other environmental issues raised in the mining process are no different than they would be for any other type of mining. For example, the digging and loading machines used to mine the sand naturally emit what the WDNR rates as “insignificant” levels of air pollution. The removal, storage and reclamation of topsoil are both regulated and monitored, with soil stockpiles being seeded and mulched to minimize fugitive dust.

Processing Frac Sand

Once the frac sand has been removed from the ground, it must be further processed to prepare it for use in the fracking process. The first step in processing is usually the crushing of larger blocks of mined rock in order to break loose the individual grains of sand. The fugitive sand regulations mentioned above cover this process as well (in Wisconsin, the particular codes are s. NR 415.075(6) and s. NR 440.688, Wis. Adm. Code), and companies must take measures to ensure that processing adheres to these regulations.

Once the sand is separated into individual grains, it must be washed to remove smaller particulates and clay deposits. This is usually done by adding water to the sand to form a slurry, which is both easier to transport and captures any fugitive dust within the water. The water used in this process is conserved and recycled through the use of settling ponds, thus minimizing the amount of water needed and keeping the fugitive dust under control.

After washing, the sand is screened to sort it by size, then stored in a stockpile to dry. Mechanical dryers are often used to complete the process, but since the washing process has removed most, if not all, of the smaller particulates, there is minimal fugitive dust raised as the sand is transferred via loaders or conveyer belts from stockpiles to dryers, then to train cars for transport to the drilling site.

Transporting Frac Sand

Both because of their own need to save on transportation costs and from a desire to minimize pollution, companies in the frac sand industry have researched the logistics of transporting sand from the mine to the wellhead, and determined that “unit trains” of 100 cars or more are the best method for transporting sand the significant distances required. Frac sand companies are collaborating with railroads to lay new track and create distribution hubs in order to minimize the number of miles that frac sand must be transported by truck. For example, Unimin Corporation, the largest frac sand company in the US market, has signed a long-term agreement with Canadian Pacific Railroad to transport its sand, and opened a rail distribution terminal in Lubbock, Texas, close to the Permian Basin drilling area.

From mining to processing, and even as far as transport, companies in the frac sand industry are taking major steps in their commitment to minimizing the impact of frac sand, both in safety and in preservation of the environment. In an industry where there is more than meets the eye, this commitment to a myriad of approaches is required to maximize safety and environmental stewardship.

What is Required to Set up a Frac Sand Mine?

What is Required to set upSay you live in Wisconsin, in the St. Peter’s sandstone area which runs through the west central part of the state. You’ve watched as neighboring towns, or perhaps your own neighbors, have signed leases with frac sand companies, or sold their properties and/or mineral rights outright to companies that will be mining for frac sand. In just three years, the number of frac sand facilities in Wisconsin alone has jumped from 7 to 145. It makes you wonder: how difficult is it to get a frac sand mine started? Can a company just bring in the excavator and start digging?

Not so fast. It turns out that there is actually a fairly complex procedure involved, with testing to do, permits to acquire, and regulations to follow. While the specifics will vary from state to state, and even county to county, below is a description of what is generally required to set up a frac sand mine, using Wisconsin as an example, since that is where three-quarters of the frac sand currently used in US oil and natural gas drilling comes from.

Determining the Quality of the Sand

The first step a company must take in setting up a frac sand mine is to determine if the sand at a particular site is desirable for fracking. There are a number of ideal characteristics for frac sand, including hardness and non-permeability of the sand grains, spherical shape, light weight and uniform size. The tiny grains of quartz sand in western Wisconsin were shaped by ancient seas, which covered the area about 500 million years ago, and they have all the characteristics that drillers seek in frac sand. Before taking on the cost of leasing or purchasing the proposed mine site, it is critical to take samples from the area to be mined and have them tested to make sure that the sand in a particular area is worth mining.

Determining the Feasibility of the Mine

Fortunately for those who would mine the St. Peter sandstone, these deposits are located relatively close to the earth’s surface, making them easy to access for testing. This also means that they can be mined at a relatively low cost—and cost is another element that must be factored into the equation. In addition to determining whether the proposed sand mine location does indeed harbor ideal frac sand in sufficient quantities to justify the cost of setting up a mine, the cost to extract and process the sand—and reclaim the area afterwards—must also be factored into the equation.

Obtaining the Necessary Permits for the Mine

If the sand is of sufficient quality and the estimated costs do not outweigh the calculated profit to be gained from the proposed mine, the next step is to lease or purchase the property or mineral rights and obtain the necessary permits to begin construction. This is where the particular requirements will vary greatly from one municipality to another, and wise company managers will spend time with local officials to make certain that they are aware of and in compliance with all necessary rules and regulations.

The first item on any to-do list is to make certain that the company is set up and licensed to do business in the state. This requires registering the business name, building a business plan, securing financing and insurance coverage, and beginning the hiring and training process for the employees necessary to initiate the first steps in the business plan.

Frac sand mining is regulated under “nonmetallic mining,” and the Wisconsin Department of Natural Resources (DNR) requires that no one may mine without first obtaining a nonmetallic mining reclamation permit. The permit process includes an initial fee, providing a reclamation plan (which includes compliance with all laws, environmental protection, zoning, and land use control), and proving the financial resources necessary to implement that plan.

Municipal governments regulate sand mines through zoning ordinances, and zoning approval for frac sand mining must be obtained ahead of time. Existing county ordinances generally trump local town ordinances. Zoning ordinances cannot be site-specific, but must be part of a comprehensive plan for the entire municipality.

Wisconsin’s constitution also allows municipal governments to regulate sand mining through general ordinances, under what are called Municipal Police Powers. This means that a frac sand mining company will need to be certain that it knows what the particular general ordinances are for the municipality where the mine is to be located, and is in compliance with all such ordinances.

In addition to zoning and local ordinances, there are a number of other permits that may need to be applied for. Examples of state, federal and local permits and approvals that might be required, depending on the specifics of the proposed mine location, include navigable waters, wetlands, water withdrawals, solid waste, wastewater discharge, air pollution, endangered species, relocation of migratory birds, mine safety, and hazardous materials.

Getting the Infrastructure in Place

In addition to all the paperwork, the company must get the mine ready for operation. This includes purchasing general business and mine-specific equipment, setting up office space, and hiring employees for both the office work and the mining operation itself.

Though sand mines seem to be exponentially cropping up in Wisconsin and other neighboring Mid-Western states, there are a lot of logistics that must be addressed prior to opening a frac sand mine. Only when all of these items have been addressed will it be possible for a company to dig the first shovelful of sand.

The Scoop—Wet and Dry—on Frac Sand Processing

The-Scoop-Wet-and-Dry-on-Frac-Sand-ProcessingThe most cost-efficient proppants for hydraulic fracturing, or fracking, are tiny grains of hard, uniformly-shaped sand. When dispersed in a fluid base and pumped into an oil or natural gas well at high pressure, these tiny grains of sand prop open fissures in the fuel-bearing shale after the pressure has been released. This allows the oil and natural gas to flow into the main wellbore for collection and processing.

However, those tiny grains of sand are themselves the result of a specific mining and processing procedure. Before this special sand is ready to be immersed in fluid for its trip to the shale seam, it must be processed through a series of steps, both wet and dry, to prepare it to become a proppant. Whether via heavy-duty conveyor systems, bucket elevators, or steep incline conveyers, the sand is transported to half a dozen stations around a frac sand processing plant in the course of becoming a proppant.

Preparing the Sand

Frac sand processing begins with the arrival of the newly-mined sand at the processing site. In some cases frac sand is processed right where it is mined, while in other instances, it must be transported to a site dedicated to preparing the sand for fracking.

In either case, the process begins with the crushing of the raw ore, also called de-agglomerating. This is because, in most cases, frac sand in its natural state is bound together with other minerals, often forming chunks of sandstone or other aggregates. These aggregates must be crushed to release the grains of sand—but not crushed with so much pressure that the sand grains themselves are cracked or shattered in the process.

The Wet Portion of a Frac Sand Plant

Once the sandstone has been crushed into its component parts, it is transported to a wash plant tower via a conveyer belt or bucket elevator. The purpose of wetting the sand is to wash it thoroughly and remove the tiny grains of agglomerating material, such as clay, which formed the bonds between sand grains in the sandstone.

This also washes away the “fines,” or tiny chips, dust, and grains of sand that are too small for the fracking process. These fines are not wasted; they are used in mine reclamation, for cow bedding, and in other manufacturing processes where tiny grains of clean sand are helpful.

This wet portion of the process also makes sure that the sand which is left is impervious to the water in which it is washed. This is important because the sand will later be mixed with the fracking fluid for injection into the well, and the sand grains must not absorb the fracking fluid, but remain suspended in it, during the pumping of the mix into the shale seam.

In addition to washing the sand, this wet stage of processing is also where the first stage of sorting takes place, with the fines and over-large grains being removed.

The Dry Portion of a Frac Sand Plant

Once the sand has been washed clean of impurities, it moves from the wet portion of the frac sand plant to the drying area. The first stage of drying involves stacking the sand in large piles, or running it along vacuum belts in order to remove as much excess water as possible. This ensures that the moisture content of the sand is as low as possible, and consistent throughout the batch, before the sand is transferred to a frac sand dryer.

The damp sand is loaded into a rotary dryer for the final drying process. These dryers are designed to dry the sand efficiently while maintaining a high throughput. Temperature controls allow the sand to be heated enough to dry it without cracking the sand grains, and the process can be modified to allow for how changing weather conditions (temperature, humidity and precipitation) might have impacted the initial drying process.

The final frac sand processing step involves screening the frac sand to sort it by size. This step is critical to giving each driller exactly the size of frac sand specified for the particular well. Grains of sand which are too large, too small, or vary too much in size will throw off the precise calculations developed for each fracking situation. Uniform grains of sand, of the correct size, will ensure that each well is fracked in the most efficient manner.

Once the frac sand is processed, it is usually stored in silos until it is shipped to the customer. This prevents any foreign material from contaminating the clean, dry, sorted sand and makes it easy to load the sand into rail cars for transport to the drilling site.

Frac sand is a critical component in the most efficient methods of drilling for oil and natural gas. Processing that sand with both wet and dry methods ensures that the sand grains will be impervious to the fracking liquid and mix well with it.

The Importance of Reclamation for a Frac Sand Mine

The Importance of Reclamation for a Frac Sand MineMining is, by its very nature, a process that disturbs the surface of the earth where the mining takes place. One of the advantages of the fracking, or hydraulic fracturing, process of drilling for oil and natural gas is its relatively small surface footprint. This is because the mines extend horizontally for hundreds of feet in many directions, along the shale lines deep underground, while maintaining only a single wellhead above ground.

Mining for frac sand is a different matter. Much of this sand lies relatively close to the surface, and the entire area must usually be excavated in order to obtain the strong, uniform spheres of silica sand that serve as proppants in the hydraulic fracturing process. This means that any frac sand mine must include land reclamation in its plan and process so that, when the deposits of sand are depleted, the land may be safely reclaimed for other uses.

A Brief History of Mine Reclamation in the US

Historically, small unproductive mines in the US were abandoned on a regular basis, and local municipalities were then faced with the need to safeguard the public from the physical hazards and environmental degradation associated with these mine locations. In 1977, Congress enacted the Surface Mining Control and Reclamation Act, which was primarily focused on reclaiming land from coal mining. As part of the implementation of this act, the Office of Surface Mining Reclamation and Enforcement (OSM) was created. It oversees the Abandoned Mine Land Reclamation Program to help address those historically abandoned mines. It also provides leadership and expertise to the states, tribes, and local groups on the forefront of mine reclamation activity today.

Why Reclaim a Frac Sand Mine?

There are a number of reasons why it is important to reclaim a frac sand mine site once the extraction process has completed. In addition to keeping the public safe, reclamation removes any toxic contaminants left over from the mining process and provides an inviting and clean habitat for wildlife. The OSM is responsible for a number of initiatives that ensure the safety of bats, dams, and fish habitats, as well as supporting technological innovations that make it easier to reclaim land through geomorphic reclamation, acid drainage prevention, and underground mine mapping.

The steady increase in US population and a rise in the cost of land also means that all available land is needed to provide space for homes, businesses and recreation. Reclaimed mine sites primarily re-establish a variety of native and other suitable plants which create soil stability and filter natural water sources at the site. While not returning the land to its exact former state, reclamation can actually make the land more usable, whether for fish and wildlife, livestock grazing, forestry, wetlands, or commercial and industrial uses.

How a Frac Sand Mine is Reclaimed

Most mine reclamation regulations are formulated at the state level. For example, Wisconsin Administrative Code NR 135 requires that new nonmetallic mines must both apply for and receive a reclamation permit prior to beginning any mining operations. The permitting process primarily requires the submission of a reclamation plan and maps which outline the steps that the company or individual will take to reclaim the land after the mining process is complete. It also requires that environmental protection measures be implemented during the mining process itself. Regulations also require a bond or other form of financial assurance that the reclamation will take place, even if the company itself fails or abandons the mine.

Part of the reason that reclamation permits must be received prior to mining is that a major factor in reclamation involves the salvage, protection, and eventual re-use of existing topsoil. Companies also need to plan how they will re-integrate unused raw materials, such as clay washed from the silica sand grains, into their reclamation process. For example, since erosion control is also a vital part of the reclamation process, that clay can provide needed additional soil stability.

Because local officials will be approving the reclamation permit, companies have to work closely with them to determine appropriate reclamation uses for the particular lands to be mined. Involving the community in brainstorming possible uses for reclaimed land is one excellent way that mining companies convey their commitment to the long-term health and viability of the land that they seek to mine.

It’s important to determine the reclaimed uses ahead of time, as these will determine the type of reclamation needed: sturdy grasses for grazing, tree seedlings for forestry, water flow patterns for wetlands or fish ponds, etc. Frac sand mine reclamation usually takes place in stages, because the area to be mined is large. This allows the raw materials and topsoil from the location currently being mined to be used in reclaiming the prior mining area. This avoids the need for a large amount of storage space and allows sections of land to be reclaimed more quickly.

As frac sand continues to grow as an industry, so too will the importance of land reclamation. Potential frac sand mine sites must include proper planning for reclamation, so that once the mining process has completed, the land may again be available for use.

The Anatomy of a Hydraulically-Fractured Well

The Anatomy of A Hydraulically Fractured WellFracking, or hydraulic fracturing, of fossil fuel wells is a fairly well-known type of drilling process in the US these days. In order to maximize the amount of oil and/or natural gas being pulled from shale beds located deep underground, tiny grains of round, hard frac sand are pumped into a well under pressure, suspended in a fluid which fractures open the rocks. The grains of frac sand then lodge in the fissures, propping them open and allowing the fossil fuels to flow to the main wellbore. To better understand exactly how fracking works, it is important to examine the anatomy of a fracking well in detail.

What is Seen Above Ground

If you come across a well site as the drilling is initially taking place, you will see a drilling rig that is similar to what you would see at any type of traditional oil or natural gas well. These tall, thin rigs with lattice-style metal frameworks reaching into the sky are used to support the drill pipes and machines used to drive those drill bits deep underground. There will also be trucks hauling concrete and pre-formed casings to the drill site.

Once the initial drilling has taken place, the drilling rig is removed. If you come across a well site when the fracking is actually occurring, you will see instead a wellhead that appears to be a series of pipes and valves. A pumper truck will be injecting fracking fluid (a composite of water, frac sand and a mix of chemicals which keep the sand suspended in the water, reduce friction, keep the wellbore clean and prevent corrosion) through these pipes into the well under pressure. Other pipes bring the recovered fracking fluid back to the surface and into open pits for temporary storage. That water is then trucked to a treatment plant; from there it might be recycled for more fracking, or even released for other uses.

Once the fracking is complete, and all excess fracking fluid and sand are flushed from the well, a second, permanent type of wellhead is installed to capture the natural gas or oil that flows up from the wellbore. In the industry, this wellhead is sometimes called a Christmas Tree, and it serves as a pump to bring the fuels to the surface and, through the pipes, into storage tanks on site. From those storage tanks, you would also see the pipelines which take natural gas to the market.

The Vertical Portion of the Well Underground

The first, upper portion of the well itself is drilled vertically. The initial part of the well, close to the surface, is sealed with one or more surface casings that are cemented into the bedrock and keep out water from any surrounding formations near the surface. This is then plugged with concrete to keep anything in the well from escaping into the surrounding soil or ground water—and also provides a solid foundation for the blowout preventer.

A hole is drilled through that concrete portion, then continues deep beneath the surface of the earth and thousands of feet below the water table. This portion of the well goes down to about 500 feet above the location of the fuel-bearing shale, which is usually between 6,000 and 10,000 feet below the earth’s surface. The well, at least down to about 4,000 feet, is lined with steel casings around which concrete is injected to further prevent any fracking fluid or fossil fuels from leaking into the surrounding rock.

At 500 feet from the target shale, the wellbore begins a slow turn from vertical to horizontal. This portion of the wellbore is lined with smaller casings, again to prevent loss of the fossil fuels into the surrounding rock.

During the fracking process, the center of the wellbore is filled with various types of fracking fluids. Once fracking is completed, the center of the wellbore is filled with fossil fuels making their way to the surface.

The Horizontal Portion of the Well Underground

By the time the wellbore is running horizontally, it has reached the line of shale that will be fracked. During the fracking process itself, a section of the shale zone is prepared by inserting a plug at the far end of it. That pumper truck inserts the fracking fluid, which arrives in the horizontal shale zone at high pressure and disperses into the shale in all directions, creating microscopic fissures in the rocks. Frac sand is lodged into these tiny fissures via that pressure, and the sand grains remain in the rock once the fracking fluid is removed. Successive sections of the shale seam are then plugged and fracked.

Once the entire section has been fracked, all the plugs removed, and the permanent wellhead installed, the oil or natural gas is allowed to flow from the tiny cracks in the shale and into the wellbore for its trip up to the earth’s surface.

The anatomy of a hydraulic fracturing well is complex and well planned. Advancements in this method of mining, in combination with developments in proppants, has allowed previously considered tapped out wells to be re-examined and further mined. Because of this, the United States has been able to maximize our at-home resources for energy.

After Mining: How Frac Sand is used in an Oil or Natural Gas Well

After Mining How Frac Sand is UsedSand has been mined in the upper Midwest in America for well over a century. Originally used for everything from children’s sandboxes and bedding for cattle to glass making and industrial sand casting, the latest sand boom has been created by the use of sand in hydraulic fracturing. Here, a particular type of sand is used as a “proppant,” propping open microscopic cracks in oil- and natural gas-bearing rocks deep beneath the surface of the earth so that the fossil fuels can flow out.

The particular type of sand needed to serve as a proppant must be uniform in size, spherical in shape, lightweight, impermeable, and able to withstand the significant pressures of the fracking process, which can be more than 9,000 pounds per square inch. Once it has been removed from the ground, processed to separate, clean and dry the grains of sand, and transported to the drilling site, this is how sand is used in the fracking process.

The Goal of Hydraulic Fracturing

The rocks which contain oil and natural gas have, over millennia, been laid down in “shale beds” deep beneath the surface of the earth. The shale rock contains pockets or “pore spaces” filled with oil or natural gas, in either a liquid or gaseous state. These must be pulled from the rock by fracturing open the pore spaces to allow the fuels to flow into the main wellbore.

Preparing for Hydraulic Fracturing

Initially, the main well bore is dug down to the shale layer. Steel casings are inserted into the wellbore and the space between the casings and the surrounding earth is filled with cement to prevent leakage of either the fracking fluid or the oil and natural gas. Then, the drilling direction is turned from vertical to horizontal, and is run for a certain distance through the shale bed. A portion of the well, in the shale zone, is then sealed off.

Hydraulic fracturing fluid is then prepared for injection into the well. The two main components of this fluid (comprising 98 percent or more of the total) are water and frac sand. As much as 4.4 million gallons of water and 10,000 tons of frac sand may be used to frack a single well. The sand must be impermeable because otherwise it would dissolve within the water before it is injected into the wellbore. This is also why the sand must be lightweight; the heavier the sand, the thicker must be the fracking fluid in order to keep the sand grains suspended in the liquid as they are pumped into the well.

Thickening the fracking fluid is one reason why the mixture also contains a small amount of other chemicals. The specific ingredients used will depend on the needs of each particular well. Generally speaking, between 3 and 12 additives are used. Guar gum thickens the mixture to help the sand grains stay suspended during transmission. Some additives reduce friction during the injection process, while others prevent microorganisms from growing in the fractures. There are special chemicals which gobble up oxygen to prevent the pipes from corroding, and acids that prevent buildup in critical areas. Each well’s exact fracking fluid composition is a closely-guarded secret held by the particular mining company.

Fracking the Well

To frack a well, as many as four sequences of fluid may be pumped into the prepared wellbore. The first fluid is water with an acid added, to clear the wellbore and mining area of any debris. The second fluid is a preparatory batch of fracking fluid without frac sand; this water initially opens the shale formation and prepares the way for the injection of frac sand. The third, and main, sequence of fluids is the fracking fluid with frac sand, and the fourth is a flushing stage, using only fresh water, to remove excess frac sand from the wellbore.

In the third stage, the fracking fluid is pumped into the sealed portion of the well, and pumps at the earth’s surface then increase the water pressure in the sealed area until it is high enough to break the surrounding shale. As the shale fractures, the fracking fluid rushes in to fill the cracks, carrying the tiny grains of frac sand with it. When the pumps are turned off and the pressure is released, the shale fractures cannot close again because the injected grains of frac sand keep them propped open. This is why frac sand must be strong enough to withstand such high pressures; both during the injection process and when the pressure is removed, tremendous forces are at work on each sand grain, initially from the water pressure, then from the gravitational forces exerted on them as the shale collapses—or tries to—under the gravitational pressure of all the rock above it.

Once the excess frac sand has been washed away by the fourth, flushing stage, oil and natural gas flow from the fractured shale into the main wellbore for collection.