Overview
The Husab uranium project is located 60 km northeast of Walvis Bay in Namibia. It covers 637 sq km and is located within the Alaskite Alley, an area that is endowed with several world class uranium deposits.
Namibia hosts two uranium mines ? Rossing and Langer Heinrich - as well as a few other uranium projects that are in different development phases.
At Husab uranium mineralization is hosted by granites. Extract Resources, the owner, had delineated two separate adjacent deposits - they contain 225 Mlbs U3O8.
A positive Definitive Feasibility Study was released in April 2011. The study demonstrates the viability of developing the Husab Uranium Project to become one of the three largest uranium mines in the world.
A conventional open pit mining operation would produce an estimated 15 million tonnes ore per year and a conventional acid leach plant would produce 15 million lbs per year U3O8 equivalent.
Based on the maiden reserve estimate Husab's mine life is 16 years.
Project cost is estimated at US$1.6 billion. "Hot" commissioning is scheduled to occur 33 months after project approval.
Location
The Husab uranium project is located in the Erongo region of central west Namibia, approximately 60 km northeast of the major deep sea port of Walvis Bay.
Erongo lies on the Atlantic shore of the country and hosts 107,000 people (2001). The port of Swakopmund is the region's capital city. It was founded in 1892 by Captain Curt von Francois. Today is a tourist spot and an example of German colonial architecture. The opening of the Rossing uranium mine helped modernize the city.
Swakopmund is also the southernmost point of the Skeleton Coast, a place that used to be called "The Gates of Hell" by Portuguese sailors. The coast is a national park and hosts a large variety of plants and animals. The climate is temperate; rainfall in Swakopmund is less than 15 mm per year.
Walvis Bay is a Namibian deep port and an important tourism center.
The project area is located in the Namib Desert in the Namib-Naukluft National Park. Mining is allowed in the park area but it is subject to stringent environmental regulations.
Husab project area is characterized by low ridges of rock, wide sand and colluvial cover, and calcrete pans, cut by deeply incised river valleys. Vegetation is sparse with trees and shrubs restricted to seasonal drainage channels.
The area is used for game farming and national parks activities.
Geology
Rifting between the Kaapvaal and Congo Cratons was followed by closure of the basin during late Neoproterozoic and early Paleozoic. This resulted in the creation of an orogen zone ? the Damara Orogenic Belt. Mineralization is associated with structural and intrusion-associated settings formed during the major thrust deformation that closed the orogen.
The licence contains the small-scale historic Ida copper mine and Husab fluorite mine which were operational during the 1970s. Uranium-bearing alaskites, similar to those at the Rossing uranium mine, are present in the Ida mine area, and elsewhere within the project area. The extensive fluorspar veins developed at the defunct Husab fluorite mine are also known to be uraniferous. The large scale alaskite (granite) hosted Rossing uranium mine, operated by a subsidiary of the global resource company Rio Tinto Plc, is located approximately 20 km northwest of Husab.
The uranium mineralization occurs as primary uraninite together with minor secondary uranium minerals in shallow, partially oxidized, or unusually high grade zones, within, and on the contacts of alaskitic granite dykes intruding the sheared contact zone between Rossing Formation marbles, and underlying Nossib Group amphibole-pyroxene schists. The uranium grades intersected by drilling are typical of this class of deposit, represented by the Rossing, Valencia and Goanikontes occurrences.
Extract has defined indicated mineral resources of 241Mt at 480ppm for 257Mlbs U3O8 at Zones 1 and 2 of the Husab Uranium Project, and inferred mineral resources of 125Mt at 400ppm for 110Mlbs U3O8 at Zones 1, 2, 3 and 4.
Further resources have been defined at the Ida Dome deposits approximately 20 km south of Zone 2.
Total Probable reserves stand at 205.0 Mt ore at 497ppm U3O8 for 224.8Mlbs U3O8.
Mining
Mining would be carried in two open pits ? Zone 1 and 2.
Stripping would be effectuated by a fleet consisting of three large electric-powered rope shovels that would mine the bulk waste on 15 m benches. In order to minimize ore loss and dilution a smaller diesel hydraulic shovels would load the ore on 7.5 m benches. The average strip ratio is 7:1. The mine envisages production of an average of 15 Mt ore per year over a 16 year mine life.
A fleet of 39 diesel electric drive haul trucks in the +300 tonne class are going to haul waste rock and ore out of the pit. Trolley-assisted hauling would also be available on most up-ramp sections.
The support equipment fleet includes graders, track and wheel dozers, front-end loaders, rock breakers and utility excavators.
Some 85 Mt of waste rock will be hauled to a Mine Residue Facility (MRF) located near the open pits which serves as a co-disposal facility for the process plant tailings.
Blasting, repair and maintenance of the mobile mining fleet and resource definition drilling are going to be outsourced.
Processing
Process flowsheet comprises crushing and milling followed by acid leaching and solid liquid separation, ion exchange, solvent extraction and precipitation.
Milling would be done by two semi-autogenous (SAG) mills. The leach circuit consists of two trains of six leaches reactors. The ion exchange process would take place in eight parallel adsorption columns. The solvent extraction is to be accomplished in a four stage counter current extraction mixer settler circuit. Precipitation would be done in a four stage gypsum precipitation circuit.
The dewatered uranyl peroxide is then dried and packaged, thus being ready for shipping.
Plant tailings are conveyed to the mine residue facility (MRF) and disposed of alongside waste rock from the mine.
Water demand is expected to reach 6.5 million cubic meters per year. Water would be sourced from a desalination plant to be constructed and operated by third parties.
Operating costs including royalties, marketing and transport are estimated at US$32.0/lb.
Environment and Community
The project received the environmental approval in January 2011.
The opening of the Husab mine is expected to result in stimulation of the local and national economy, and offers the prospect of significant investment, direct and indirect job creation, infrastructure development and a contribution to the creation of wealth in the region, extending into communities well beyond those directly associated with the Project.
During operation, the project would employ approximately 1,050 persons. During construction, the project would create up to 4,000 temporary employment jobs. The majority of employees are going to be Namibian citizens.
Royalties of 3% of revenue (estimated at US$30M per year) will be payable to the government. Further fiscal benefits will accrue to the Namibian government including corporate taxes (equal to 37.5% of profits), duties and taxes on imports, and income taxes on employees' salaries.
