NEWS

Vancouver, British Columbia – May 29, 2015 – NioCorp Developments Ltd. (“NioCorp” or the “Company”) (TSX: NB, OTCQX: NIOBF, FSE: BR3) today announced changes to its management team and an update on its corporate headquarters.

After six and a half years of service, Mr. Peter Dickie has elected to retire from the Company and will be stepping down from his roles as President and Board member of NioCorp, effective May 31, 2015. The Company’s remaining Board of Directors, management team, and employees would like to thank Mr. Dickie for his dedicated service to the Company and for the invaluable role he has played. Mr. Dickie has agreed to provide consulting services to the Company on an as needed basis, in order to ensure a smooth transition. In light of Mr. Dickie’sretirement, the Board has appointed Mark A. Smith to assume the additional role of President, effective June 1, 2015.

In conjunction with Mr. Dickie’s retirement, the Company also announced that, effective immediately, NioCorp’s headquarters is being relocated from Vancouver, BC Canada to Denver, Colorado USA, where its senior management team is now based. This move will facilitate more efficient management of day-to-day development operations at the Company’s Elk Creek, Nebraska mine site.

Effective May 26, 2015, Mrs. Teresa McGowan has been appointed to the role of Senior Manager of Investor Relations. Mrs. McGowan brings significant buy-side and sell-side experience to the role, and most recently served as the Senior IR Specialist at DigitalGlobe Inc., an NYSE listed company.

“On behalf of NioCorp’s board of directors and its shareholders, we thank Peter for his tremendous efforts and contributions to the Company, and the key role he played in bringing the Company and the Elk Creek niobium resource to this key juncture,” said Mark A. Smith, CEO of NioCorp. “Peter was instrumental in obtaining purchase options for mineral rights and the early development of the Elk Creek Project. Thanks to his efforts, following completion of the Feasibility Study and funding efforts,the Company expects to move into the construction phase of the Elk Creek mine development in 2016.”

Smith added, “We also welcome the addition of Teresa McGowan to the NioCorp team. As Senior Manager of Investor Relations, Teresa brings substantial experience and knowledge that will become increasingly important as NioCorp continues on its path to rapid development of the Elk Creek mine.”

About the Company:  NioCorp is developing the only primary niobium deposit known to be under development in the U.S., and the highest grade undeveloped niobium deposit in North America, located near Elk Creek, Nebraska.  The Company has filed a resource estimate completed in accordance with NI43-101 reporting standards with an effective date of February 20, 2015 reporting an Indicated Resource of 80.5 million tonnes grading 0.71% Nb2O5, 2.68% TiO2 and 72 ppm Sc and an Inferred Resource of 99.6 million tonnes grading 0.56% Nb2O5, 2.31% TiO2 and 63 ppm Sc (at a 0.3% Nb2O5 cutoff grade).  Niobium is mainly used in the form of Ferro-Niobium to produce HSLA (High Strength, Low Alloy) steel, which is a lighter, stronger steel used in automotive, structural and pipeline applications.  The U.S. imports 100% of its niobium needs.  Titanium in the form of an oxide is used extensively as a pigment in paints, plastics and papers.  As a metal, titanium is used in aerospace applications, armor, chemical processing applications, marine hardware applications, medical implants, power generation and in sporting goods. Scandium is used in solid oxide fuel cells (SOFCs) and aluminum-scandium alloys, as well as in ceramics, electronics, lasers and lighting applications.

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

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 plansor 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 labour 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.