Reno Creek ISR Plan Uses Production Units of 80 to 100 Wells and a Carbonate Lixiviant With Ion Exchange

The technical report and resource audit for Uranium Energy Corporation's Reno Creek ISR project in Campbell County, Wyoming, dated December 31, 2018, describes phased well fields feeding a central processing plant.

The Technical Report and Audit of Resources of the Reno Creek ISR Project, Campbell County, Wyoming, was prepared by Behre Dolbear for Uranium Energy Corporation and is dated December 31, 2018. It describes the in-situ recovery (ISR) method planned by AUC, the project operator. The report notes that ISR has worked in fluvial and shoreline sandstone deposits in Wyoming, Nebraska, Texas and Kazakhstan, and gives a general guideline that recovery is about 70% of the in-place resource estimated from surface drilling.

Critical Data

Overview

AUC plans a phased, iterative ISR operation in which it builds and runs a series of production units in turn. Each production unit has its own well fields with a header house serving 80 to 100 wells. All production wells are completed so that they can serve as either injection or recovery wells, which allows effective uranium recovery and later groundwater restoration.

The lixiviant oxidizes the uranium with gaseous oxygen, hydrogen peroxide or another oxidant and complexes it with bicarbonate. It is injected into the mineralized sandstone, the production zone aquifer, through injection wells that are drilled, cased, cemented and tested for mechanical integrity. Recovery wells pump the pregnant lixiviant to the header house and through buried pipelines to the central processing plant (CPP).

Key Process Stages

Well field. Injection and recovery wells follow a 5-spot pattern, adjusted to the shape of the mineralization, with injection wells typically 75 to 125 ft apart. Interior monitor wells sit within each production unit, and an exterior monitor well ring around it detects any horizontal movement of lixiviant beyond the well field.

Bleed. Slightly more water is recovered than injected, so that groundwater flows inward into the production unit. The difference, the well field bleed, is adjusted as needed to keep that inward gradient.

Ion exchange. In the CPP, uranium complexes are loaded onto ion exchange resin in pressurized down-flow columns.

Elution and precipitation. Uranium is eluted from the resin and precipitated from the eluate.

Drying and packaging. The precipitate is filtered, dried and packaged.

Lixiviant make-up. Carbon dioxide and/or carbonate-bicarbonate and oxidant are added to the barren lixiviant, which is recycled to the production units.

Additional Interesting Data and Summary

The report states that ISR removes uranium selectively, generates no tailings and causes only limited surface disturbance, with vegetation re-established over production units and pipeline corridors during operation. AUC's confidence in the method rests on a site-specific pilot test by RME at Reno Creek, together with bench-scale bottle roll and column leach studies that showed uranium could be mobilized and recovered with a carbonate lixiviant. AUC has bought 40 acres for the CPP near the intersection of Wyoming Highway 387 and the Clarkelen County Road, already equipped with buildings, power, telephone and water.

In summary, the Reno Creek plan is a conventional Wyoming carbonate ISR operation, with phased production units feeding a single ion exchange plant, supported by a site pilot test.

Key Processes

• In-situ recovery with carbonate/bicarbonate lixiviant and oxidant
• 5-spot injection and recovery well patterns
• Well field bleed for inward groundwater gradient
• Pressurized down-flow ion exchange
• Elution and uranium precipitation
• Filtration, drying and packaging
• Lixiviant reconstitution and recycle

Source: Technical Report and Audit of Resources of the Reno Creek ISR Project, Campbell County, Wyoming, USA, prepared by Behre Dolbear for Uranium Energy Corporation, December 31, 2018.