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Red Leaf Resources
The Division of Water Quality (DWQ) is seeking public comment, until September 27, 2013, on a draft Ground Water Permit to Red Leaf Resources for the operation of a single Early Production System (EPS) test capsule on state land to extract kerogen from oil shale ore.
Kerogen is fossilized material in shale and other sedimentary rock that yields oil when heated. This process, known as retorting, uses extreme heat (pyrolysis) to separate the oil from the rock.
The enclosed EPS capsule will be approximately three-fourths the size of the capsules planned for commercial production of oil shale. Red Leaf plans to use the EPS capsule to evaluate various technical, environmental, and economic aspects of this new kerogen extraction technology.
This draft permit covers the operation of the EPS capsule only. Should Red Leaf wish to construct and operate additional capsules for commercial production, it must report its findings on waste containment and monitoring results for the EPS capsule to DWQ and apply for a major modification to this permit.
Basis for Issuing the Ground Water Permit
DWQ has concluded that Red Leaf's construction of the EPS capsule, as presented in Red Leaf's ground water discharge application, will not degrade the beneficial uses of ground water in the area. DWQ based its decision, in part, on the following factors:
- The process does not use water or involve wastewater containment.
- Spent shale will be dry and not have any significant water content.
- Spent shale will be enclosed in a three-foot layer of bentonite-amended shale (BAS).
- Leachate produced from mining operations appears to have levels of dissolved contaminants that are comparable to, or less than, the levels in existing ground water in underlying rocks.
- Rock located immediately below the EPS capsule is of very low permeability and protects underlying aquifers from any contaminants that could possibly be released from the capsule.
The rock formation underlying the permit area consists of fine-grained, low-permeability sedimentary rock. This rock behaves as an aquiclude, creating a barrier to the flow of ground water and preventing precipitation from infiltrating and recharging the underlying rocks.
Red Leaf conducted a seep and spring inventory in October 2012 and again in May 2013 to document any changes in conditions due to spring runoff or precipitation. The company found few springs or seeps in its October survey and no distinctly new springs or seeps in the May survey. Water from these seeps has a much lower total dissolved solids (TDS) content and lower pH than ground water from the rocks in the shallow subsurface. A comparison of the water chemistry of the seeps and springs with the shallow ground water and subsurface water resulting from precipitation indicates that precipitation does not infiltrate very deeply below the ground's surface. Given the nature of the ground water at the site, these seeps and springs appear to be very shallow, localized areas of saturation recharged by precipitation.
A well drilled on the site encountered ground water at 630 and 830 feet beneath the surface. Ground water at this depth contained TDS at much lower levels than the shallow ground water wells, indicating that the shallow ground water does not flow into the deeper aquifer below.
Capsule Extraction Process
Red Leaf will remove overburden and ore from the pit area and place a three-foot layer of bentonite- amended shale (BAS) on the graded bedrock surface to act as a liner. The company will place well-graded road-base material on top of the lower BAS liner followed by an insulation layer. A steel liquids-collection pan installed within this layer will collect liquids from capsule operation. A bulkhead along the north margin of the capsule floor will tie the heating and oil shale recovery pipes in the capsule to six conveyance tunnels in bedrock underneath the capsule. Layers of overburden on top of the metal pan will act as insulation to conserve heat and protect the BAS liner. Red Leaf will stack between 100 to 160 feet of oil shale ore on top of this bottom insulating layer for processing. Natural or processed gas will fire a burner to heat the pipes and recover the oil shale from the ore.
Red Leaf will be evaluating the use of flexible membrane liners (FMLs) to contain liquid and gaseous hydrocarbons during processing, both along the sides of the capsule and as a cover for the top during retorting. A primary function of the BAS/Capsule liner, however, is long-term, permanent containment of the spent shale after capsule closure. DWQ does not consider FMLs to offer containment beyond the design life of the liner. A 3-foot cap of BAS will remain in place or be installed on top of the capsule prior to closure and surface reclamation.
Monitoring Requirements in the Permit
Red Leaf is constructing the EPS capsule to evaluate capsule design for future commercial production. To better assess any potential discharge to the subsurface or surface waters from large-scale commercial production at the mine, Red Leaf is required to conduct the following analyses as conditions of their permit:
- Analyze representative samples of spent shale following closure and cooling of the EPS capsule for general chemistry, specified heavy metals, and petroleum-related compounds.
- Evaluate the condition of any upper BAS liner used after retorting to determine how much settling occurred and examine areas of the liner that experienced the greatest strain due to settlement during the extraction process.
- Investigate the hydrologic properties of the spent shale as well as the hydraulic properties of the capsule components using the Hydrologic Evaluation of Landfill Performance (HELP) model to estimate how much water could infiltrate the upper capsule liner.
- Monitor and sample discharges from the capsule after ore retorting operations have ended. This will include drainage from the metal pan at the base of the oil shale, the top of the BAS liner below the metal pan, and the six tunnels that lead from the bulkheads for the inflow and outflow of hot gases and collection of liquid and gaseous hydrocarbons from the metal pan.
In addition, Red Leaf will conduct Synthetic Precipitation Leaching Procedure (SPLP) testing on spent shale from the retorting process as part of its report on capsule performance. This testing will evaluate the leachability of the capsule contents.
While Red Leaf will use the overburden and other waste rock excavated from the mine in capsule construction, it will not enclose this waste rock in a liner following capsule closure. There is a possibility that precipitation may react with this waste rock material and leach contaminants. Because the waste rock is not contained in lined cells as the spent shale is, the resulting discharge may enter surface or shallow ground water. Red Leaf will analyze a representative sample of waste rock using SPLP testing to evaluate whether waste rock leachate could be a problem and help develop appropriate methods to manage storm water, if necessary.
Public Comment Period
A 45-day public comment period ended on September 26, 2013.