HMC from the stockpile will be fed to the first section of a mineral separation plant

The Kwale Mineral Sands project is an advanced-stage development project located in Kenya, approximately 40km south of Mombasa. Valued at $60m, the project is owned and operated by Base Resources, which acquired it from Vaaldiam Mining in August 2010.

The project is undergoing an enhanced definitive feasibility study, which is slated for completion in the second quarter of 2011. Construction will begin by mid-2011, and the mine will begin production by mid-2013. Annual production is projected to be 330,000t of ilmenite, 80,000t of rutile and 40,000t of zircon.

The project is expected to be one of the top producers of ilmenite and rutile in the world, with production amounting to nearly 10% and 14% of the global supply of these minerals respectively. It is suitably positioned to leverage on a sustained opportunity in the mineral sands market, and is expected to generate $1bn in revenues over its lifetime of 11 years. Gold Mining Equipment

TZ Minerals International predicts that from 2015 sulphate will reach $130/t, ilmenite $715/t, and rutile and zircon $1,300/t. On the total product revenue, Vaaldiam Mining will earn a 1.5% royalty.

Reserves

The project reserves, based on the central and south dunes, are estimated to be 38.5 million tons graded at 6.8%

At the north dune, an additional resource of 116 million tons grading 2.1% total heavy mineral (THM) has been identified which, though not included in the project reserve estimate, will be evaluated as an extension opportunity.

Geology and mineralisation

The deposit is hosted within the Magarini Sands formation, a series of low hills that form a parallel belt to the coast. The formation lies with slight unconformity with the Shimba grits and Mazeras sandstone of the Upper Triassic age that form part of the upper Duruma sandstone. The Duruma sandstone series is one of three rock divisions dominating the regional geology of the project.

“The project is expected to be one of the top producers of ilmenite and rutile, amounting to nearly 10% and 14% of global supply respectively.”

The Magarini formation includes unconsolidated sediments that have originated from the Duruma sandstone series. Magarini Sands have been deposited as coastal dunes in an Aeolian environment during the Pliocene age.

The Kwale deposit is poorly stratified with the stratigraphic sequence, comprising layers of brown, orange, reddish beige and pinkish sand. Brown sand is found at the surface, with orange, red, beige and pink coloured sand following at deeper depths in the same order. Weathered sandstone from the basal formation is found at the bottom of the deposit. White sand and clay are found at the base of several holes.

The silt fraction of the deposit is in the range of about 15% and 30%. Heavy minerals including ilmenite, rutile and zircon are hosted regionally in abundance.

The deposit area contains three mineralised zones, namely the central dune, south dune and the north dune. The central dune measures 2km in length, 1,250m in width and is on an average 29m thick in two horizons. The upper horizon typically has more than 5% THM grade, higher than the lower horizon where THM grades average between 1% and 5%. Grades in the northern part of the dune exceed 10%. The heavy mineral content is, on an average, 5.7% across the dune.

The south dune is 4.5km long, 600-800m wide and has an average thickness of 19m. The heavy mineral content is 3.5%. The north dune extends 2km in length and has a width of 500-1,000m. The ore envelope within the dune continues to a depth of 66m. Within this area, the heavy mineral content averages 2.1% THM.

Mining

The proposed mining method for the Kwale deposit includes the use of continuous mining techniques, bucket wheel excavators and overland conveyors. Mining for the first four years will be carried out at the rate of 8.8 million tons per year, and gradually increased to 12.5 million tons per year as the grade reduces. Graphite Mill

“The proposed mining method for the Kwale deposit includes the use of continuous mining techniques, bucket wheel excavators and overland conveyors.”

Processing

Ore processing will follow conventional mineral sands separation techniques. Ore will be transported via an overland conveyor system to the plant run-of-mine where it will be separated into direct plant feed and stockpiled excess. Following wet screening and desliming, the feed ore will be processed in a primary concentrator spirals circuit to produce heavy mineral concentrate. Through a slimes thickener, water will be recovered and returned to the process water reservoir. Thickened slime from the spiral plant, along with the sand tailings, will be sent to the residue storage areas. crushers

HMC from the stockpile will be fed to the first section of a mineral separation plant. The HMC-recovered ilmenite will be stored. The remaining minerals will be upgraded by using HMC to separate the quartz and the gangue heavy mineral.

The non-magnetic concentrate, post drying, will undergo conventional magnetic and electrostatic separation processes that will result in a rutile product and a small additional ilmenite stream. The remaining zircon-enriched sand will be treated in a wet gravity separation plant to remove the gangue heavy minerals. The zircon-rich concentrate will be again dried and processed with electrostatic and dry magnetic equipment. The final product will be transported 50km via road tankers to the export facility close to Mombasa.