NioCorp Demonstration Plant Achieves Key Phase 1 Milestone

Successful production of high-purity calcium and magnesium carbonates from Elk Creek ore points to potential efficiency gains in NioCorp's processing flow sheet as well as possible new commercial products for the Project, once sufficient project financing is obtained to allow the Project to proceed

CENTENNIAL, Oct. 25, 2022 - NioCorp Developments Ltd. ("NioCorp" or the "Company") (TSX: NB) (OTCQX: NIOBF) today announced that its demonstration-scale processing plant (the "demonstration plant") in Quebec, Canada has now completed demonstrating its planned process for removing calcium and magnesium from ore obtained from the Elk Creek Critical Minerals Project (the "Project").

This positive result, which is part of Phase I operations of the demonstration plant, is a key milestone in NioCorp's proposed optimization of its process flow sheet for the Project, which was designed by L3 Process Innovation ("L3") and NioCorp.

The well-known and time-tested process NioCorp is employing to remove calcium and magnesium carbonates from the ore using thermal treatment and leaching is part of the demonstration plant's Phase I flowsheet. This step has operated successfully, and the removed calcium and magnesium were produced at demonstration scale as a mixed calcium and magnesium carbonate. Removing carbonate minerals in this fashion is expected to reduce the size of the follow-on planned production steps and make them more efficient.

Characterization of the calcium and magnesium carbonate from demonstration plant production runs has demonstrated very low levels of impurities, and an overall 99% purity of the mixed calcium-magnesium carbonate.

The Elk Creek resource is a carbonatite and its mineralization is predominantly carbonate minerals. The Elk Creek Project Mineral Resource estimate does not include calcium or magnesium as sufficient exploration and sampling has not been completed to determine whether there are reasonable prospects for eventual economic extraction. In light of these results, however, the Company expect to conduct an assessment of adding these two elements to the Mineral Resource as well as to assess the potential salability of the material that was produced from the demonstration plant, once sufficient project financing is obtained to allow the Project to proceed.

Phase I demonstration plant operations will continue with calcination and a ramp-up of leaching operations as testwork and assembly of Phase II and Phase III of the demonstration plant's planned operations proceed in parallel.

"The team at L3 has been working very hard to complete Phase I of the demonstration plant and deliver results. We look forward to the completion of the remainder of the demonstration plant operations, and most importantly, the rare earth metallurgical performance metrics showing the full potential economic benefits of rare earths for the Elk Creek Project," said Scott Honan, NioCorp's Chief Operating Officer.

QUALIFIED PERSONS:

Eric Larochelle, B.Eng., Co-Owner, L3 Process Development, a Qualified Person as defined by National Instrument 43-101, has reviewed and approved the technical information contained in this news release.

For More Information:

Jim Sims, Corporate Communications Officer, NioCorp Developments Ltd., 720-639-4650, jim.sims@niocorp.com

@NioCorp $NB.TO $NIOBF $BR3 #Niobium #Scandium #rareearth #neodymium #dysprosium #terbium #ElkCreek #EV #electricvehicle

About NioCorp

NioCorp is developing a critical minerals project in Southeast Nebraska that will produce niobium, scandium, and titanium. The Company also is evaluating the potential to produce several rare earths from the Project. Niobium is used to produce specialty alloys as well as High Strength, Low Alloy ("HSLA") steel, which is a lighter, stronger steel used in automotive, structural, and pipeline applications. Scandium is a specialty metal that can be combined with Aluminum to make alloys with increased strength and improved corrosion resistance. Scandium is also a critical component of advanced solid oxide fuel cells. Titanium is used in various lightweight alloys and is a key component of pigments used in paper, paint and plastics and is also used for aerospace applications, armor, and medical implants. Magnetic rare earths, such as neodymium, praseodymium, terbium, and dysprosium are critical to the making of Neodymium-Iron-Boron ("NdFeB") magnets, which are used across a wide variety of defense and civilian applications.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the United States Private Securities Litigation Reform Act of 1995 and forward-looking information within the meaning of applicable Canadian securities laws. Forward-looking statements may include, but are not limited to, statements about NioCorp's expectation that its demonstration plant will produce results that will increase efficiencies in NioCorp's planned processing flow sheet, NioCorp's expectation that NioCorp may be able to produce new commercial products for the Project, NioCorp's ability to secure sufficient project financing to complete construction and commence operation of the Elk Creek Project; the outcome of current recovery process improvement testing, and NioCorp's expectation that such process improvements could lead to greater efficiencies and cost savings in the Elk Creek Project; the Elk Creek Project's ability to produce multiple critical metals; and the completion of the demonstration plant and technical and economic analyses on the potential addition of magnetic rare earth oxides to NioCorp's planned product suite Forward-looking statements are typically identified by words such as "plan," "believe," "expect," "anticipate," "intend," "outlook," "estimate," "forecast," "project," "continue," "could," "may," "might," "possible," "potential," "predict," "should," "would" and other similar words and expressions, but the absence of these words does not mean that a statement is not forward-looking.

The forward-looking statements are based on the current expectations of the management of NioCorp and are inherently subject to uncertainties and changes in circumstances and their potential effects and speak only as of the date of such statement. There can be no assurance that future developments will be those that have been anticipated. Forward-looking statements reflect material expectations and assumptions, including, without limitation, expectations, and assumptions relating to: the translatability of the thermal treatment and leaching process to remove calcium and magnesium carbonates from ore to the ore that NioCorp expects to extract from the Elk Creek Project. Such expectations and assumptions are inherently subject to uncertainties and contingencies regarding future events and, as such, are subject to change. Forward-looking statements involve a number of risks, uncertainties or other factors that may cause actual results or performance to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those discussed and identified in public filings made by NioCorp with the SEC and with the applicable Canadian securities regulatory authorities and the following: NioCorp's ability to operate as a going concern; NioCorp's requirement of significant additional capital; NioCorp's limited operating history; NioCorp's history of losses; cost increases for NioCorp's exploration and, if warranted, development projects; a disruption in, or failure of, NioCorp's information technology systems, including those related to cybersecurity; equipment and supply shortages; current and future off take agreements, joint ventures, and partnerships; NioCorp's ability to attract qualified management; the effects of the COVID-19 pandemic or other global health crises on NioCorp's business plans, financial condition and liquidity; estimates of mineral resources and reserves; mineral exploration and production activities; feasibility study results; changes in demand for and price of commodities (such as fuel and electricity) and currencies; changes or disruptions in the securities markets; legislative, political or economic developments; the need to obtain permits and comply with laws and regulations and other regulatory requirements; the possibility that actual results of work may differ from projections/expectations or may not realize the perceived potential of NioCorp's projects; risks of accidents, equipment breakdowns, and labor disputes or other unanticipated difficulties or interruptions; the possibility of cost overruns or unanticipated expenses in development programs; operating or technical difficulties in connection with exploration, mining, or development activities; the speculative nature of mineral exploration and development, including the risks of diminishing quantities of grades of reserves and resources; claims on the title to NioCorp's properties; potential future litigation; and NioCorp's lack of insurance covering all of NioCorp's operations.

Should one or more of these risks or uncertainties materialize or should any of the assumptions made by the management of NioCorp prove incorrect, actual results may vary in material respects from those projected in these forward-looking statements.

All subsequent written and oral forward-looking statements concerning the matters addressed herein and attributable to NioCorp or any person acting on its behalf are expressly qualified in their entirety by the cautionary statements contained or referred to herein. Except to the extent required by applicable law or regulation, NioCorp undertakes no obligation to update these forward-looking statements to reflect events or circumstances after the date hereof to reflect the occurrence of unanticipated events.

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SOURCE NioCorp Developments Ltd.