The Project is hosted within the Elk Creek Carbonatite. By definition a carbonatite is an igneous rock body with greater than 50% modal carbonate minerals, mainly in the form of calcite, dolomite, ankerite, or sodium- and potassium-bearing carbonates. Carbonatites commonly occur as intrusive bodies, such as isolated sills, dikes, or plugs, although rarely occur as extrusive rocks. Many carbonatites are associated with alkali silicate rocks (for example, syenite, nepheline syenite, ijolite, urtite, pyroxenite, etc.). Carbonatites are usually surrounded by an aureole of metasomatically altered rocks called fenites. Carbonatite-associated deposits can be classified as magmatic or metasomatic types (Richardson and Birkett, 1996).

The property hosts niobium, titanium, and scandium mineralization as well as REE and barium mineralization that occur within the Elk Creek Carbonatite.

The current known extents of the high grade niobium, titanium, and scandium are approximately 750 m along strike, 400 m wide, and 800 m in dip extent below the unconformity.

The current known extents of the low grade niobium, titanium, and scandium are approximately 830 m along strike, 500 m wide, and 850 m in dip extent below the unconformity.

Niobium and Titanium Mineralization
The deposit contains significant concentrations of niobium. Based on the metallurgical test work completed to date at a number of laboratories using QEMSCAN® analysis, the niobium mineralization is known to be fine-grained, and that 77% of the niobium occurs in the mineral pyrochlore, while the balance occurs in an iron-titanium-niobium oxide mineral of varying composition. Within the mineralized Carbonatite, there are 14,284 samples of Nb2O5, the maximum Nb2O5 grade is 4.472%, and the mean Nb2O5 grade is 0.518%.

Scandium Mineralization
Within the Elk Creek Carbonatite, a host of other elements exist with varying degrees of concentration. The Company has completed both whole rock analysis and multi-element analysis
on all samples for the 2014 program, plus re-sampling of selected historical core and/or pulps between 2011 and 2014.

As the metallurgical test work advanced during 2014 and 2015, the ability to obtain a titanium dioxide (TiO2) and scandium (Sc) product became apparent. TiO2 is typically found to be related to the niobium grades with a range of 3:1 to 4:1 found within the core of the deposit. The scandium mineralization does not directly correlate to niobium mineralization but does show a grade increase with increasing niobium at low grades and high grade Scandium (>75 ppm) is also associated with higher grade concentrated distributions of CaO, Mgo, Th, U and Pb and As.

Rare Earth Element Mineralization
Within the Elk Creek Carbonatite complex, there are several occurrences of REE mineralization, including the Project. REE mineralization within the Carbonatite occurs within the following minerals:
• Bastnäsite ([Ce,La,Y]CO3F)
• Parisite (Ca[Ce,La]2[CO3]3F2)
• Synchysite (Ca(Ce,La)(CO3)2 F)
• Monazite ([Ce,La]PO4).

The mining method selected for this ore body was based on economic parameters and geotechnical information, ensuring it was suitable for the mineralization geometry. Due to its depth and requirement for selectivity in mill feed grades, the underground longhole stoping method (LHS) was selected. Given the bulky geometry of the deposit, a block caving or sub-level caving method could have possibly been economically viable. However, the limited selectivity of such methods would not allow for optimizing the higher value of this deposit given their production constraints. To maximize the recovery of the high grade zones, a longhole stoping method utilizing paste backfill was used.

The stopes dimensions are 15 m wide, and stope length varies based on Nb2O5 mineralization grade to a maximum of 25 m per panel with a level spacing of 40 m. The variation on stope length allowed for optimization of the Nb2O5grade with a minimal increase to operating costs. The level spacing of 40 m was beneficial to operating and sustaining capital costs. Each block is mined with a bottomup sequence. A partial sill pillar level is designed to be left between these two mining fronts/blocks. The extraction of ore from the partial sill pillar level is expected to be 62.5% using production upholes through 25 m of the 40 m thick sill pillar and is accounted for within the reserves. This methodology will allow partial mining of ore on the sill pillar level, while at the same time allowing the development of the lower mining block and establishing an early start to the mining of the upper mining block. Using this approach minimizes the impact on initial capital investment. The backfill was designed to have an adequate strength to allow for mining adjacent to filled stopes, thus eliminating the need for rib pillars. The backfill will have an adequate strength to allow for mining adjacent to filled stopes, thus eliminating the need for rib pillars.

The mine design and schedule were based on a milling constraint (2,764 tpd), provided by NioCorp, to produce approximately 7,000 t/y of ferroniobium and a LOM of over 36 years. Optimization work indicated that the grade of Nb2O5, (0.81%) at a unit NSR over US$ 500/t could sustain and produce a consistent ferroniobium production over the LOM. The mill production rate was established at 2,764 t/d from which an annualized production averaging approximately 7,220 t of ferroniobium per year is derived. Scandium trioxide and titanium dioxide accompany the ferroniobium production in the mine plan.

The stope width is a constant 15 m, and vertical height is 40 m from floor to floor. The length of the stopes is on average 19 m ranging from 10 m to a maximum panel length of 25 m. The mine plan stope orientation is perpendicular to the general strike of the deposit, which is 20° off the measured principal stress. Nordmin does not feel that this offset will have a significant impact on stope stability. The actual mine plan stope lengths have a maximum length of 25 m in both fresh and moderately weathered rock.

The stopes are accessed through a footwall drive with about 25 m offset from the stopes. The crosscuts (x-cuts) are driven in the center of the stopes from the footwall drives. These drives are connected by the ramp system, ventilation raises and on some levels they are connected to the production shaft. Most of the mine infrastructure is located in waste, but some areas can be in lower grade material as it gets closer to the ore body.

There is a significant increase in the overall depth and vertical extent of the mined ore zone from the previous SRK 2017 feasibility study. The designed vertical extent is 600 m with a bottom elevation of -495 m, versus the previous vertical extent of 450 m with a bottom elevation of -375 m. To efficiently develop the increase in depth and vertical extent, the production shaft and exhaust system (ventilation shaft), were excavated to lower depths. The ventilation shaft is designed to a 530 m depth versus the previous ventilation raise depth of 386 m. The production shaft is designed to a 755 m depth versus the previous depth of 440 m. The deeper production shaft and related crushing and conveying system is complemented with an ore pass and waste pass system that results in an overall material handling system that has suitable ore storage above and below the crusher station, fewer haulage trucks, and fewer ventilation requirements.

The mine utilizes drill jumbos for lateral development equipped with tophammer drills. Production stope drilling utilizes down-the-hole drills. Rock bolters are used for ground support, and probe holes will be used to support mine grouting where required. The mine will operate a fleet of 40- tonne haul trucks being loaded by 6.2 m3 (14 t) LHDs. The ore is fed through grizzlys with rock breakers into an underground crusher and via a material handling system to the surface. The mine has full infrastructure underground including ventilation, pumping system, electrical substation and distribution system, warehousing, explosives storage, communications system, and maintenance garage. The mine will have a staff of approximately 216 people at the peak of production.

The ROM ore will be crushed underground in a primary crusher, and the crushed product with a top size of 203 mm and characteristic size (Pao) of 115 mm, will be delivered to the crushed ore bin located at the surface. The ore from the bin will be reclaimed by three vibrating feeders with a total capacity of 136 t/h and passed on to the secondary crusher circuit via the secondary crusher screen feed conveyor.

At the secondary crushing stage, the ore will be sized on a dry, double deck screen with a top deck aperture size of 50 mm and bottom deck aperture size of 25 mm. The screen oversize from both decks will report to the secondary crushing stage. The screen undersize will be conveyed to the HPGR circuit.

The screen oversize fractions will be crushed in a single secondary cone crusher operating with a closed side setting of 25 mm. The secondary crushed product will be sized by the same double deck screen with the primary crusher discharge ore.

The screen undersize, at an approximate characteristic particle size (Pao) of 22 mm, will be further crushed in the HPGR circuit. The HPGR circuit will consist of a single HPGR crusher, with a separate double-deck vibrating screen with top and bottom deck aperture sizes of 6 mm and 3 mm, respectively. The recirculating load of the HPGR circuit is expected to be in the range of 30 to 40% of the circuit new feed.

The HPGR screen undersize will be the final comminution product and is expected to have a characteristic particle size (Pao) of 1.1 mm. The ore will be stored in a fine ore bin, then reclaimed by a vibrating feeder with a design capacity of 132 t/h, and then passed on to the acid leach circuit via the acid leach feed conveyor for further processing.

Hydrometallurgical Plant
The role of the hydrometallurgical (Hydromet) plant is to separate the three pay elements Nb, Ti, Sc, from the crushed ore while utilizing processes to minimize the operating cost of the plant. This requires a large amount of acid, both Hydrochloric (HCl) and Sulphuric (H2SO4). The Hydromet plant includes acid recovery processes to lower the operating expense of the process by requiring a small amount of fresh acid and sulphur to be brought onsite. The HCl and H2SO4 recoveries are 99% and 85% respectively. The other operating cost reduction comes from utilizing impurities in the ore separated out in the process as reagents in the process, which minimizes the need for fresh reagents brought onsite. The added benefit to utilizing impurities as reagents reduces the amount of tailings from the process that needs to go to the Tails Storage Facility (TSF), reducing the overall size of the storage area.

The hydrometallurgical process is divided into fi ........