Privately owned mining company CIC Resources is making progress in delineating its resource at its Alto Paraná project, following its announcement last year of the discovery of what may be the world’s largest titanium deposit in Paraguay, and is conducting furnace tests in South Africa.
CIC Resources president and CEO David Lowell says the combination of this large resource and low mining, concentrating and smelting costs could provide the titanium project with the potential to be an important factor in the world’s titanium market.
The company’s on-site pilot tests, which began late last year and ended at the start of this year, saw the process being success- fully facilitated in a demonstration plant with a production rate of 5 t/d.
In February, South Africa’s national min- eral research organisation, Mintek, began pro- duction smelting tests of a 110 t concentrate sample in an arc furnace, in Johannesburg. The final furnace design is expected to include a prereduction circuit.
“This circuit allows the throughput to be doubled and cheaper subbituminous coal to be used instead of electricity. The preliminary assessment of smelting is good, based on a crucible scale lab test and computer simulation. The concentrate is unusually clean, containing low triuranium oxide, thorium and calcium oxide. We hope to produce 90% titanium dioxide slag,” says Lowell.
However, he believes that many mining operators would be sceptical of this discovery as it is the first extremely large and relatively high-grade titanium dioxide laterite deposit.
“The 9.09-billion-ton resource used in the scoping study comprises 7% titanium dioxide cutoffs, 7.6% titanium dioxide and 23.6% iron oxide (largely magnetite – it also contains limonite, which is not recovered). The orebody has a 6.4 m thickness. At a 5% cutoff, the resource consists of 24.58-billion tons of 6.8% titanium dioxide and 22.3% iron oxide with an average thickness of 7 m. The delineation of the resource is also essentially complete and closer-spaced sampling will be performed as part of the mining operation. The stripping ratio of the ore and terrain is 0:1 because the deposit extends to the ground surface and the ore and the terrain are nearly horizontal,” explains Lowell.
A polygon resource calculation was made to determine these figures, including a statistical study on rate of change in grade. The scoping study also uses kriging – a group of geostatistical techniques.
Despite the softness of the ore, the deposit stands at a height of between 8 m and 10 m, he says.
The ore is also extremely homogenous and, throughout the deposit, there is little change in grade and characteristics. The concentrate can be put into an arc furnace with no further treatment as it is made up of clean, fine-grained ilmenite and magnetite, which occur in the upper 6.5 m of a nearly horizontal laterite zone.
At least 518 pits, 8 m deep, and 464 one-metre-deep recon- naissance (recon) pits have been sampled. The recon pits included the known limits of the orebody. The hand-dug pits were irregularly spaced at up to 2 000 m apart.
“In the recon drilling, we found that the first 1 m intercept from the surface accurately repre- sented the grade of the 6.5 m ore interval,” says Lowell.
Pit sampling on a 1 000 m grid has been completed and a limited area is being tested with 7 m auger holes on a 250 m × 250 m grid of holes. Over 100 of these drill holes have been completed.
Processing technology has been developed in-house and is used for the recovery of tita- nium heavy sands, using a differential settling and a magnetic separation process for successfully separating minerals such as magnetite, titanomagnetite and ilmenite, from light and smaller-grained clay.
Lowell says the patented mineral separation process, called the Kuhn process, is new and has been developed by metallurgical consultant and Tuscon Minerals Advisory Group principal Dr Martin Kuhn.
The process uses gravity and magnetic separation and produces nontoxic products. The process is similar to some technology used in the clay industry, Lowell says.
Water is recirculated to produce a high concentration of total tailings solids, which can be used to backfill mined areas to develop new farming land.
The operational and capital expenditures of this processing method are fairly low, as the ore requires no crushing or grinding.
A paved highway and high- voltage power lines pass through the project and low-cost power from the world’s second-largest hydroelectric facility, at Itaipu dam, is the economic driving force for this project, he says.
The scoping study, which is being conducted by Hains Engineering, in Toronto, Canada, is almost complete but the start date of the bankable feasibility study and the mining operation has not been decided. CIC Resources is pleased that the scoping study internal rate of return is above 20%.
The projected production scale is currently 500 000 t/y of titanium dioxide slag and a similar tonnage of high-quality pig iron, reveals Lowell. Revenue from the project will be derived equally from two products, chloride-grade titanium and high-quality pig iron.
This will be the second- largest titanium dioxide ope- ration in the world and the first large mining operation in Paraguay, with the Paraguay Congress modifying its mining code to facilitate the development of Alto Paraná, he said.
“The new code is based largely on the Peruvian and Chilean codes. It allows more area to be held by one Paraguayan company and decreases the holding costs during the prospecting and exploration phases. The original code was written when there were no mines in Paraguay and the old code was in part unusable,” explains Lowell.
The prospecting and exploration phases of the mining code allow four to eight years, but exploration is now essentially complete.