CENTENNIAL, Colo. – September 4, 2015 – NioCorp Developments Ltd. (“NioCorp” or the “Company”) (TSX: NB, OTCQX: NIOBF, FSE: BR3), is pleased to announce that it has filed its second Preliminary Economic Assessment (PEA2) for its Elk Creek Project with SEDAR.

On Friday, September 4, 2015 NioCorp filed a technical report prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”), by be SRK Consulting (U.S.), Inc. and Roche Ltd., Consulting Group. The results of the PEA2 were previously announced by the Company on August 4, 2015, and included the following:

• Pre-tax NPV of US$3.07 billion.
• Pre-tax IRR of 31.7%.
• After-tax NPV of US$2.30 billion.
• After-tax IRR of 27.6%.
• Average pre-tax cash flow of US$438 million
• An increase in annualized Scandium Trioxide production to 97 tonnes.
• Annualized Ferroniobium production of 7,490 tonnes.
• Annualized Titanium Dioxide production of 23,960 tonnes.

“The PEA2 reflects significantly improved economics for the Elk Creek Project when compared to the initial PEA announced in April of this year,” said Mark A. Smith, Executive Chairman of NioCorp. “With the increased economic valuation of this project, we are now focusing our efforts on finalizing the Feasibility Study and securing additional off-take agreements with customers in the Niobium, Titanium, and Scandium markets. These areas of focus will greatly assist our continuing discussions with the financial community in our effort to bring this valuable project into production.”

The full PEA2 technical report is now available for download on SEDAR at www.sedar.com, as well as on NioCorp’s website at www.niocorp.com.

Qualified Person:

Jeff Osborn, BSc Mining, MMSAQP of SRK Consulting (U.S.), Inc., a Qualified Person as defined by National Instrument 43-101, has overall responsibility for SRK portions of the Elk Creek Preliminary Economic Analysis and has read and approved the technical information contained in this news release.

About NioCorp:

NioCorp is a mineral development Company pursuing high-quality natural resources. The Company’s main focus is the Elk Creek Niobium Project, which is an advanced niobium and scandium exploration initiative located in southeast Nebraska. Niobium is used to produce High Strength, Low Alloy (“HSLA”) steel, which is a lighter, stronger steel used in automotive, structural, and pipeline applications. Scandium is used as an alloy with aluminum, dramatically increasing strength without sacrificing corrosion resistance.

For further information, contact Teresa McGowan, Senior Manager of Investor Relations at (720) 639-4650 or at [email protected]

Special note about forward-looking statements:
Neither TSX nor its Regulation Services Provider (as that term is defined in the policies of the TSX) accepts responsibility for the adequacy or accuracy of this release.

Certain statements contained in this press release may constitute forward-looking statements. Such forward-looking statements are based upon NioCorp’s reasonable expectations and business plan at the date hereof, which are subject to change depending on economic, political and competitive circumstances and contingencies. Readers are cautioned that such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause a change in such assumptions and the actual outcomes and estimates to be materially different from those estimated or anticipated future results, achievements or position expressed or implied by those forward-looking statements. Risks, uncertainties and other factors that could cause NioCorp’s plans or prospects to change include 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; and the risks involved in the exploration, development and mining business. NioCorp disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise. Readers are advised that the Elk Creek PEA is preliminary in nature and includes Inferred Mineral Resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves. There is no certainty that the preliminary economic assessment will be realized. Mineral Resources are not Mineral Reserves because they do not have demonstrated economic viability. There is no guarantee that Inferred Mineral Resources will be converted to the Measured and Indicated Mineral Resource categories and, therefore, there is no guarantee that the project economics described herein will be achieved.

CENTENNIAL, Colo. – September 4, 2015 – NioCorp Developments Ltd. (“NioCorp” or the “Company”) (TSX: NB, OTCQX: NIOBF, FSE: BR3), is pleased to announce that it has filed its second Preliminary Economic Assessment (PEA2) for its Elk Creek Project with SEDAR.

On Friday, September 4, 2015 NioCorp filed a technical report prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”), by be SRK Consulting (U.S.), Inc. and Roche Ltd., Consulting Group. The results of the PEA2 were previously announced by the Company on August 4, 2015, and included the following:

• Pre-tax NPV of US$3.07 billion.
• Pre-tax IRR of 31.7%.
• After-tax NPV of US$2.30 billion.
• After-tax IRR of 27.6%.
• Average pre-tax cash flow of US$438 million
• An increase in annualized Scandium Trioxide production to 97 tonnes.
• Annualized Ferroniobium production of 7,490 tonnes.
• Annualized Titanium Dioxide production of 23,960 tonnes.

“The PEA2 reflects significantly improved economics for the Elk Creek Project when compared to the initial PEA announced in April of this year,” said Mark A. Smith, Executive Chairman of NioCorp. “With the increased economic valuation of this project, we are now focusing our efforts on finalizing the Feasibility Study and securing additional off-take agreements with customers in the Niobium, Titanium, and Scandium markets. These areas of focus will greatly assist our continuing discussions with the financial community in our effort to bring this valuable project into production.”

The full PEA2 technical report is now available for download on SEDAR at www.sedar.com, as well as on NioCorp’s website at www.niocorp.com.

Qualified Person:

Jeff Osborn, BSc Mining, MMSAQP of SRK Consulting (U.S.), Inc., a Qualified Person as defined by National Instrument 43-101, has overall responsibility for SRK portions of the Elk Creek Preliminary Economic Analysis and has read and approved the technical information contained in this news release.

About NioCorp:

NioCorp is a mineral development Company pursuing high-quality natural resources. The Company’s main focus is the Elk Creek Niobium Project, which is an advanced niobium and scandium exploration initiative located in southeast Nebraska. Niobium is used to produce High Strength, Low Alloy (“HSLA”) steel, which is a lighter, stronger steel used in automotive, structural, and pipeline applications. Scandium is used as an alloy with aluminum, dramatically increasing strength without sacrificing corrosion resistance.

For further information, contact Teresa McGowan, Senior Manager of Investor Relations at (720) 639-4650 or at [email protected]

Special note about forward-looking statements:
Neither TSX nor its Regulation Services Provider (as that term is defined in the policies of the TSX) accepts responsibility for the adequacy or accuracy of this release.

Certain statements contained in this press release may constitute forward-looking statements. Such forward-looking statements are based upon NioCorp’s reasonable expectations and business plan at the date hereof, which are subject to change depending on economic, political and competitive circumstances and contingencies. Readers are cautioned that such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause a change in such assumptions and the actual outcomes and estimates to be materially different from those estimated or anticipated future results, achievements or position expressed or implied by those forward-looking statements. Risks, uncertainties and other factors that could cause NioCorp’s plans or prospects to change include 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; and the risks involved in the exploration, development and mining business. NioCorp disclaims any intention or obligation to update or revise any forward-looking statements whether as a result of new information, future events or otherwise. Readers are advised that the Elk Creek PEA is preliminary in nature and includes Inferred Mineral Resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as Mineral Reserves. There is no certainty that the preliminary economic assessment will be realized. Mineral Resources are not Mineral Reserves because they do not have demonstrated economic viability. There is no guarantee that Inferred Mineral Resources will be converted to the Measured and Indicated Mineral Resource categories and, therefore, there is no guarantee that the project economics described herein will be achieved.