Current and Projected Water Use in the Texas Mining and Oil and Gas Industry

Abstract

In the middle of 2009, we undertook a study of water use in the mining industry in Texas, both current and projected for the next 50 years. The study concerned the upstream segment of the oil and gas industry (that is, water used to extract the commodity until it leaves the wellhead), the aggregate industry (sand and gravel and crushed rock operations, washing included but no further processing), the coal industry (mostly pit dewatering and aquifer depressurizing), and other substances mined in a fashion very similar to that of aggregates (industrial sand, lime, etc.), as well as through solution mining. In general, we followed the definition of mining according to SIC/NAICS codes. It follows that cement facilities, despite their large quarries, are considered to belong to the manufacturing, not mining, category. The objective of the study, essentially prompted by the sudden increase in shale-gas production, was to assist in the next cycle of water planning by the state agency in charge of such planning, the Texas Water Development Board (TWDB).

The approach to the study is twofold:

  1. To collect water-use data and auxiliary information by contacting actual mining facilities.
  2. To interview experts and other knowledgeable individuals in their respective fields to fill in the gaps in water-use data and to understand future development/contraction of water use in the different segments of the mining industry.

We surveyed the industry either through formal questionnaires sent to the membership of trade associations (TACA for aggregates; TMRA for aggregate, coal, and uranium; TXOGA and others for oil and gas), through surveys sent to water providers/observers such as GCDs, or through survey results from other organizations (MSHA, RRC, TCEQ, TWDB, USGS), and especially private vendors of the oil and gas industry. We contacted and had in-depth interviews with multiple representatives of every major segment of the mining industry to help us understand how the water is used, how much is recycled, what its source is (groundwater, surface water, or something else), whether it is fresh or brackish (saline water use is not tallied in this study), how much is rejected outside of the mining facility, etc.

Results from the surveys were useful but not as extensive as needed to fully assemble a representative sample of the hundreds of mining facilities in the state, with the exception of the coal industry and the uranium industry. We were also able to gather relatively accurate data from the stimulation stage when a well is being readied for production (that is, the fracking process), but we are more uncertain about water use for drilling wells and waterfloods. Results of current water use for the aggregate industry relied on previous information somewhat calibrated and updated by survey results. Overall, in 2008 (latest year with complete information), we estimate that the state used approximately 160 thousand acre-feet (AF) in the mining industry (Figure ES1), including 35.8 thousand AF for fracking wells (mostly in the Barnett Shale/Fort Worth area) and approximately 21.0 thousand AF for other purposes in the oil and gas industry, although more spread out across the state, with a higher demand in the Permian Basin area in West Texas. The coal industry used 20.0 thousand AF along the lignite belt from Central to East Texas. The 71.6 thousand AF used by the aggregate industry is distributed over most of the state, but with a clear concentration around major metropolitan areas. The remainder amounts to 11.0 thousand AF and is dominated by industrial sand production (approximately 80% of total).

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