Elk Creek Project in the US state of Nebraska is a critical minerals project that will produce niobium, scandium and titanium minerals. The project also hosts various amounts of all rare earth elements.

US-based mineral development company NioCorp Developments fully owns mineral rights to Elk Creek and is also the operator.

An updated feasibility study of the project was completed in 2022.

All major local, state and federal permits required to commence construction have been received.

The critical minerals project is expected to have a mine life of 38 years producing an average of 7,348 tonnes per annum (tpa) of ferroniobium, 102tpa of scandium trioxide and 12,063tpa of titanium dioxide.

Elk Creek location details

The Elk Creek Project is located approximately 75km southeast of Lincoln, Nebraska, and 110km south of Omaha, Nebraska.

According to the technical report feasibility study effective June 2022, the property includes one 91.5ha (226 acres) parcel of land owned by NioCorp Developments and eight option-to-purchase agreements that compass around 565ha area.

The property can be accessed via road or from one of the regional airports.

NioCorp conducted two drilling campaigns at the project- one in 2014 and another in 2015 for hydrogeological and geotechnical studies.

Geology and Mineralisation

The Elk Creek Project hosts a niobium, scandium, titanium and rare earth-bearing carbonatite deposit. The Elk Creek Carbonatite had intruded older Precambrian granitic and low- to medium-grade metamorphic basement rocks.

The carbonatite and precambrian rocks are unconformably overlain by around 200m of Palaeozoic marine sedimentary rocks. Due to the thick cover, the carbonatite was identified and targeted through magnetic surveys and drilling activity.

The carbonatite, which hosts niobium (reported as Nb2O5), titanium (reported as TiO2) and scandium (reported as Sc), is made of mainly dolomite, calcite and ankerite, as well as chlorite, barite, phlogopite, pyrochlore, serpentine, fluorite, sulphides and quartz.

Niobium is contained within the mineral pyrochlore, while REE mineralisation occurs as bästnasite, parisite, synchysite and monazite.

Mineral Resource Estimate

According to the 2022 feasibility study, the Elk Creek Project hosts an estimated 632.9 kilotonnes (kt) of contained total rare earth oxides (TREO) in the indicated mineral resource category.

The Mineral Resource Estimate for niobium, titanium, and scandium in the indicated category is 188.8Mt grading at 0.51% Nb2O5 for 970.3kt Nb2O5; grading at 2.24% TiO2 for 4,221kt TiO2; 60.06ppm Sc for 11,337t Sc.

Inferred resource is at 108.3Mt grading at 0.39% Nb2O5 for 426.6kt Nb2O5; grading at 1.92% TiO2 for 2,082kt TiO2; 52.28ppm Sc for 5,660.2t Sc.

Mining and ore processing

The underground long-hole open stoping method is expected to be used at the Elk Creek deposit. The mining process was selected on the basis of geotechnical information and mineralisation geometry.

Paste backfill method will also be used to enable high recovery of ore material.

The stopes will be 15m wide and up to 25m per panel with a level spacing of 40m based on Nb2O5 mineralisation grade.

Each block will be mined with a bottom-up sequence.

From the partial sill pillar level, ore extraction is expected to be 62.5% using production upholes through 25m of the 40m thick sill pillar.

This will allow partial mining of ore on the sill pillar level as well as enable the development of the lower mining block and support an early start to the mining of the upper mining block.

There will be two shafts excavated using conventional shaft sinking methods along with a freezing process through the first 200m from the surface.

The mine will operate a fleet of 40-tonne haul trucks loaded by 14-tonne LHDs (load, haul, dump). The ore is fed through grizzly feeders with rock breakers into an underground crusher and transferred to the surface via a material handling system.

The Mineral Processing equipment will be housed within a single large building.

The ore from the mine will be crushed underground in a primary crusher and then delivered to the crushed ore bin located at the surface.

The ore will be further crushed in the secondary crushing stage on a dry, double-deck screen.

The Hydrometallurgical Plant will extract the pay elements- Nb, Ti, Sc, from the crushed ore as well as separate impurities through the use of 15 units including acid recovery processes.

The Pyrometallurgical Plant will reduce niobium pentoxide in the Hydromet feed and convert it into a saleable ferroniobium (FeNb) metal.

Elk Creek project infrastructure

The Elk Creek project will include surface and underground infrastructure, as well as surface tailings and salt storage facilities.

Key surface infrastructure will include a fuel storage and dispensing system; process water treatment centre; sanitary wastewater collection system and access roads among others.

Underground facilities will include fuel storage and filling area, a warehouse, offices, an electrical distribution system, a water pumping and discharge system, compressed air distribution, and the backfill distribution system among others.

A new high-voltage transmission line will provide power to an on-site primary substation. A 44kV transmission line will be built to send power from the primary substation to the mine substation. The power infrastructure will also include a 13.8kV on-site power distribution network.

Contractors involved

Mining consultancy firm SRK Consulting worked with NioCorp Developments for the development of the Elk Creek mine. This included a review of the extensive work conducted by Molycorp in the 1970s and 1980s.

In April 2015, NioCorp completed a positive Preliminary Economic Assessment (PEA) study for the Elk Creek Niobium project. The study was carried out by SRK Consulting and Roche of Quebec.

The 2017 Feasibility Study was conducted by SRK Consulting (US), with the support of Tetra Tech, SMH Process Innovation, MineFill Services, and Olsson Associates.

The feasibility-level technical report of the project, effective June 2022, was prepared by Dahrouge Geological Consulting, Understood Mineral Resources, Optimize Group, Cementation, Tetra Tech, SRK, Adrian Brown Consultants, Metallurgy Concept Solutions, Magemi Mining, L3 Process Development, BBE Consulting and CDM Smith.

In May 2014, NioCorp selected West-Core Drilling for drilling operations at the Elk Creek Project.

In November 2017, Rockies Express Pipeline received a contract to construct and operate a 27.8-mile natural gas pipeline for the Elk Creek Superalloy Facility.

In November 2019, NioCorp Developments selected Zachry Group as the engineering, procurement, and construction (EPC) firm for the surface processing facilities and associated infrastructure of Elk Creek Project.

In October 2019, Cementation USA, a part of the Cementation Americas Group, was selected as the lead EPC contractor for the underground aspects of the project. The company was again selected in February 2021 for detailed engineering work.

DuPont Clean Technologies was contracted by NioCorp for engineering and procurement activities related to the project's sulphuric acid recycling plant, while Veolia Water Technologies won the contract for engineering and procurement activities for the mine’s water treatment plant.

Olsson was associated with Elk Creek to provide support with state and federal permitting efforts.

Offtake Agreements

In December 2014, NioCorp Developments signed an offtake agreement with ThyssenKrupp Metallurgical Products. Under the deal, ThyssenKrupp Metallurgical Products, a commodity trading company, will buy around 3,750 metric tonnes of NioCorp’s planned Ferro-Niobium production from Elk Creek deposit for ten years with an option for extension.

CMC Cometals, a division of Commercial Metals Company in the US, signed a commercial sales agreement in June 2016 to purchase up to a maximum of 1,875 tonnes per year, or 25%, of NioCorp’s potential annual ferroniobium production.

In April 2020, NioCorp entered into a non-binding letter of intent (LoI) with an unnamed US-based steel producer related to 25% of NioCorp’s production of ferroniobium over the first ten years of production from the property.

Traxys North America agreed to buy up to 120 tonnes of scandium trioxide over the first ten years of operation of the Elk Creek project.

NioCorp’s business combination

In March 2023, NioCorp Developments completed a business combination with GX Acquisition Corp. II.

Under the terms of the transaction, a wholly owned US-based subsidiary of NioCorp merged with GXII, with the latter becoming the surviving entity.

GXII was renamed as Elk Creek Resources Corp., following the closure.

The deal listed NioCorp on Nasdaq Stock Exchange as well as gave the company with access to new capital for the development of the Elk Creek Project.