NEWS

Vancouver, British Columbia – April 20, 2015 – NioCorp Developments Ltd. (“NioCorp” or the “Company”) (TSX: NBOTCQX: NIOBFFSE: BR3) wishes to announce the following update to the positive Preliminary Economic Assessment (PEA) study for the Elk Creek Niobium project announced April 13, 2015.

Company officials were advised by the authors of the report that a computational error was discovered in the formula pertaining to one section of the report.  The error resulted in a portion of the projected revenue not being accounted for in early years of the project, which, together with consequent adjustments to estimates for tax liabilities, resulted in an adjustment to the NPV and IRR results.  After correction for this calculation, the Company reports the following amendments to the summary provided on April 13:

– Pre-tax NPV of US$ 875 million with an IRR of 16.6% (previously reported as US$ 821 million with an IRR of 15.7%)
– After-tax NPV of US$ 606 million with an IRR of 14.6% (previously reported as US$ 562 million with an IRR of 13.9%)
– Average pre-tax cash flow of US$ 178 million (previously reported as US$ 177 million).

There were no additional changes to the PEA.

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.

These results will form part of the discussion of the PEA being held at 9:00 AM eastern time April 20th, 2015.  Interested parties are reminded the call-in numbers are as follows:

Participant Line (North America) – (855)-756-7520 Ext 28394#
Participant Line (Europe) – (001)-515-888-2012

Jeff Osborn, BSc Mining, MMSAQP of SRK Consulting (US) Inc., a Qualified Person as defined by National Instrument 43-101, has overall responsibility for the Elk Creek Report 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.