NEWS

Vancouver, British Columbia – May 19, 2015 – NioCorp Developments Ltd. (“NioCorp” or the “Company”) (TSX: NBOTCQX: NIOBFFSE: BR3) is pleased to announce the filing of a positive Preliminary Economic Assessment (PEA) study for the Elk Creek Niobium project.

On Friday, May 15th, NioCorp filed a technical report prepared in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101“) in support of an independent PEA prepared by SRK Consulting (U.S.) and Roche Ltd, Consulting Group on the production of Niobium at its Elk Creek Project in Southeast Nebraska (“The Technical Report“).

“As we noted in our April 13th press release, we view the PEA results as an important milestone for the development of the Elk Creek Resource.” said Mark Smith, Executive Chairman and CEO of NioCorp.  “With the full report now published, everyone can see the level of detailed analysis that has accompanied our work plan to date and we look forward to the completion of the feasibility study for the project.”

This Technical Report filing is in support of the Company’s April 13, 2015 and April 20, 2015 news releases. The Technical Report is available on SEDAR at www.sedar.com and on NioCorp’s website at www.niocorp.com

Jeff Osborn, BSc Mining, MMSAQP of SRK Consulting (US) Inc., a Qualified Person as defined by National Instrument 43-101, is responsible for the Elk Creek Preliminary Economic Assessment Study and has read and approved the technical information contained in this news release.

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 the Company at (604) 568-7365 or at www.NioCorp.com

ON BEHALF OF THE BOARD

“Peter Dickie”

Director, President

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.