InKai

Overview

The Inkai uranium mine is located in a remote part of southen central Kazakhstan and is operated by Joint Venture Inkai (JVI), which is owned by Cameco (60%) and KazAtomProm (40%). Cameco is the world's largest publicly traded uranium company - it is based in Saskatoon, Saskatchewan, Canada.

At Inkai there are two production areas (blocks 1 and 2) and an exploration area (block 3).

Commercial mine production began in 2009, using in situ recovery (ISR) technology. This was followed the commissioning of the main processing plant in 2010, allowing uranium yellowcake (U3O8) to be milled and drummed on site. Inkai employed up to 200 workers during construction and will require nearly 500 employees as it moves to full production. 

As of December 2011, Inkai had a reserve of 99.5 million pounds U₃O₈  and current licensed capacity (approved in principle) of mine and mill of 3.9 million pounds.

It is ISO 14001 and BSI OHSAS 18001 certified.

Cameco has an application pending to increase licensed capacity to 5.2 million pounds per year.

Location

Inkai is located in a remote part of south central Kazakhstan a former Soviet republic. The country covers 2.7 million square kilometers and is the world's largest landlocked country.

The site is about 20km by road from the nearest village and 370km from the regional capital, Chimkent.

The climate is continental, with warm summers and cold winters. Precipitation varies between arid and semi-arid conditions.

Geology & Mineralization

Cretaceous to Neogene age continental clastic sedimentary rocks. The Cretaceous-Cainozoic Chu-Sarysu basin extends for more than 1,000 km from the foothills of the Tien Shan Mountains located on south and southeast sides of the basin and merges into the flats of the Aral Sea depression to the northwest. The basin is up to 250 km wide, bordered by the Greater Karatau Mountains on the southwest and the Chuskoa uplift on the northeast. The basin is composed of gently dipping to nearly flat lying fluvial-derived unconsolidated sediments composed of inter-bedded sand, silt, and local clay horizons.

The Cretaceous-Cenozoic sediments host several stacked and relatively continuous, sinuous "roll-fronts", or oxidation-reduction (redox) fronts hosted in the more porous and permeable sand and silt units. Several uranium deposits and active uranium ISR mines are located at these regional oxidation roll-fronts, developed along a regional system of superimposed mineralization fronts. The overall stratigraphic horizon of interest in the basin is approximately 200 to 250 m in vertical section. 

The Inkai deposit is a roll-front uranium deposits. It is hosted within the Inkuduk and Mynkuduk Formations which comprise feldspathic sandstones or sub-arkoses, typically containing 50% to 60% quartz and 10% to 15% feldspar. Clay content is in the range of 5% to 10%. The redox boundary can be readily recognised in core by a distinct colour change from grey on the reduced side to yellowish stains on the oxidized side, stemming from the oxidation of pyrite to limonite. In cross-section, the redox boundary is often "C" shaped forming the classic roll-front. 

Mining & Operation

The Inkai project uses the in situ recovery (ISR) mining method. ISR mining produces no waste rock or tailings and results in minimal disturbance to the surface and underground areas mined.

Uranium occurs in sandstone aquifers as coatings on the sand grains at a depth of up to 300 metres.

Uranium is largely insoluble in the native groundwater which is not potable due to naturally high concentrations of radionuclides and dissolved solids. Using a grid of injection and production wells, a mining solution containing an oxidant is circulated through the orebody to dissolve the uranium. 

Processing

The uranium-bearing solution (generally containing less than 1/10 of 1% uranium) is then pumped to a surface processing facility where the uranium is removed using ion exchange resin. The water is re-oxidized and re-injected into the orebody. The uranium is stripped from the resin, precipitated and then dried to form the final product, yellowcake. This process is repeated to remove as much uranium as is economically feasible. When mining at the site is complete, the groundwater will be restored to its original quality.

This is a closed loop recirculation system since the water from the production well is reintroduced in the injection wells. Slightly less water is injected than is pumped to the surface to ensure that fluids are confined to the ore zones intended for extraction. Monitor wells are installed above, below and around the target zones to ensure that mining fluids do not move outside a permitted mining area.

The ISR operation has been approved and licensed for 3.9 million pounds U3O8 per year. An application is pending to increase the operational capacity to 5.2 million pounds U3O8 per year.

Environment & Community

The ISR extractive method is environment friendly because of simplicity of the process ensures maximum worker safety and minimal exposure to radiation. 

ISR uses native groundwater that is unusable for drinking, agriculture or livestock because of its proximity to the uranium orebody. Comprehensive modeling of groundwater flow ensures mining solutions remain separated from any potential sources of moveable water in the area around Inkai. Natural dilution of mining solutions will ensure that groundwater returns to its pre-mining quality over time and that mining initiatives will have no impact on potential sources of drinking water in the area. No waste or tailings facility are required. Surface of the mining operation can be easily restored to its original state.