These formations are made of silicates (urtite, ijolite, and okatite) which join at the outer edges of the rings, while the sovites (carbonate rocks of which calcite is the major component) are blended into the formations, also forming the heart of the two loops.

The niobium mineralizations within the Oka complex are generally primary and magmatic. The average sovite content, dominating the complex’s facie, is approximately 0.25% Nb₂O₅. The ore bodies at the St. Lawrence Columbium (SLC) property have levels of Nb₂O₅ of 0.45% to 0.50%. Niocan’s S-60 zone has an average grade of 0.66%. These mineralized deposits have no net limits, as found in vein type deposits, but are progressive depending on the economic value of niobium. These are tabular deposits, lense-shaped from five metres to ten metres wide, stretching parallel to its encasing formation from 200m to 300m. These subvertical lenses are characterized by a very good continuity; at SLC and Niocan, these mineralized deposits are known to depths of 750 and 500 metres respectively.

According to a doctoral thesis by Gold at McGill University in 1963, there are apparently five intrusive phases forming the genetic sequence of the formations. First, there is the sovite intrusion which makes up the largest part of the formation, followed by the okatite intrusion, then the ijolites and finally, the late arrival of hydrothermal fluids, containing high levels of pyrochlore, along the subvertical fractures.

Three mineralized zones are defined within the Niocan property. Two of them, the HWM-1 and the HWM-2, are concordant and sub-parallel to the edge of the carbonatite formation. These zones have a thickness of some ten to thirty metres and are over 300 metres long.

The S-60 deposit is a vertical chimney of an elliptical shape whose main axis is some 120m and the smaller one is 80m. This deposit was defined by drilling to a depth of 500m. It is made up of three main facies. The skarn, a coarse-grain rock, is mainly made up of magnetite (20%), apatite (10%), forsterite (30%) and calcite (40%). It represents some 50% of the deposit. A forsterite sovite and white biotite and magnetite soviets make up the other mineral facies of the deposit. The skarn is probably a forsterite sovite, which is significantly enriched by magnetite, apatite, and pyrochlore through residual liquids from the carbonatite magma.

Niobium is essentially found within the pyrochlore mineral, but perovskite and niocalite are also found in the HWM-1 and HWM-2 zones.

The pyrochlore minerals, analyzed by Dr. Louis Bernier of Géoberex Research, has a Nb₂O₅ concentration varying between 31% and 62% by weight, while the size of the grains vary from 0.1mm to 3.5mm. The size of the pyrochlore grains, which is visible to the naked eye, is the main reason why recovery exceeded 80% in a pilot mill test. The grain sizes of the three existing producers is such that they can not be seen with the naked eye, and therefore have recovery levels that are far inferior to those recorded with the Niocan deposits.

The pyrochlore from the S-60 formation contains approximately three times less uranium than that from the SLC site. On the other hand, Dr. Bernier’s mineralogical findings during his analysis of pyrochlore mineral and concentrate samples from S-60 indicate that the radioactive elements uranium and thorium, as well as rare earths metals, are present within the crystalline structure of the pyrochlore.

WORK UNDERTAKEN BY NIOCAN

Niocan’s management has benefited from the expertise and extensive experience of many professional engineers and management of the old SLC niobium mine, which operated from 1960 until 1976.

Two drilling campaigns: 1995 to 1997

From the onset of the drilling program in 1995, the S-60 deposit began to take form as a deposit whose shape was previously not known within the Oka complex and whose mineral content was 50% higher than that mined at the SLC operation.

Forty-two diamond drill holes intersected the S-60 deposit up to a depth of 500m on sections spaced 15m apart. This is a very massive and compact deposit. The rock is of high quality, as seen by using the Rock Quality Designation (RQD) assessment. Core sample recovery in the deposit was 100% and the RDQ is usually higher than seventy.

Reserve Assessment

Reserve calculations were made on the S-60 and HWM-2 deposits. Two different methods were used: the section method and the geostatistical method. The geostatistical method was only used on the main deposit, S-60.

Thirty-eight (38) drill core samples revealed an ore density of 3.0 to 3.2 for the S-60 deposit and a density of 2.8 for the HWM-2 deposit.

Reserves for the S-60 deposit were calculated to a drilled depth of 500m and those of the HWM-2 deposit up to 350m. These were verified and certified by geologists from the Met-Chem/SNC-Lavalin consortium who were responsible for the feasibility studies. Only proven and probable reserves were used for the study.

Tonnes (millions). Content cut-off 0.44% for S-60 and 0.50% for HWM-2.

Average content of the S-60 deposit in magnetite (Fe₂O₃) is 9% and 4.5% in P₂O₅.

Metallurgical Concentration Tests

Numerous tests and analyses were undertaken throughout the exploration phase of the program. These were done by the Centre de Recherche Minérale du Québec, under the supervision of Met-Chem and Mr Jean-Claude Caron, President of the consulting firm, PROTEC Inc. These initial tests on the various mineralized facies of the S-60 deposit allowed Niocan to develop an optimized pyrochlore recovery process.

The pilot plant test was done in Quebec City using drill core mineral samples from all mineralized intersections of the S-60 deposit. Once crushed and thoroughly mixed, the sample represented a good average for the entire deposit. This test confirmed that the mineral recovery rate will exceed 80%.