In 2008, the first natural gas energy companies started exploring the deep layers of shale hidden one and half miles below the surface of the countryside of Pennsylvania, New York, Ohio and West Virginia. There they discovered a homegrown source of energy. It brought these states a billion-dollar development which meant new jobs, new-found riches, and some of the lowest unemployment numbers in the U.S.
It also brought anxiety for the environmentalists, worries about ground water pollution and above-ground contamination, and in some communities, divided opinions and bickering from those who had hit pay dirt to those who had not.
Shale gas refers to natural gas that is trapped within shale formations. Shale is fine-grained sedimentary rock that can be rich sources of petroleum and natural gas. Over the past decade, the combination of horizontal drilling and hydraulic fracturing (fracking) has allowed access to large volumes of shale gas that were previously uneconomical to produce.
The production of natural gas from shale formations has rejuvenated the natural gas industry in the U.S. Marcellus Shale is one of the largest natural gas fields in the world. Around 2,000 to 7,000 feet below the Marcellus formation is the Utica Shale formation extending from Quebec, Canada, south to Kentucky with major concentrations in Pennsylvania, Ohio and West Virginia.
The good news is the availability of large quantities of shale gas should enable the U.S. to consume a predominantly domestic supply of gas for many years and produce more natural gas than it consumes. The bad news … roads are being destroyed.
Destruction of roadways
Roads that used to carry farm-to-market traffic are now required to carry hundreds of trucks with loads that contain drilling pad equipment, water and additives such as sand, and chemicals to help in the fracking processes.
Some of these roads within the Marcellus and Utica shale drilling fields can carry hundreds of loads of water per day. In the very early days of natural gas drilling in the Marcellus and Utica Shale formations, the last consideration was the state and local roadways. State and local roadways became impassable even with a four-wheel drive vehicle.
In some of the more rural Pennsylvania counties, many of the roads are still made of dirt and gravel. It took little time to destroy these roads. Even the improved roadways that had many applications of oil and chip and hot mix asphalt became victims of the increased traffic and axle loadings.
In the beginning, large quantities of aggregate where merely laid and spread on the surface of the roads. As these aggregates migrated to the shoulders of the road, clogging drainage ditches and rutting deeper, more aggregate was added. With each application, the height of the roadway increased. Soon property owners were faced with driveways too steep and unstable to reach the road.
If the design life of a county road is approximately 30 years, the impact of every 1,000 extra trucks on that county road would decrease the roadways lifespan by 13% (taking into account that a county road would average 1,000 vehicles a day). In most areas with shale gas drilling, the truck count is increased dramatically when the fracking operation starts, which means hundreds of trucks carrying water venture onto improved and unimproved roadways.
The idea of using aggregate to cover over or keep the roadway in some kind of reasonable shape gave way to traditional hot mix asphalt applications. With unstable subbase problems, however, it was apparent that not just the surface course but the subbase its self was in need of stabilization.
The effects on an unimproved roadway are instantaneous with movement of the road materials and sub soils. Some improved roads may take a day to start showing signs of fatigue and then failure. Nearly all local and state governments understand that this degradation of their highway system will take place when drilling and fracking operations are close at hand. This type of road damage will lead to extraordinary monetary cost.