Orosur Mining Inc. – Reports High Grade Drill Results, Including 5.00g/t Au over 23m, 4.89 g.t over 13.9m and 4.86 g/t Au over 25.0m at Anzá, Colombia

Orosur Mining Inc. ("Orosur” or "the Company”) (TSX/AIM: OMI) the South America-focused gold producer, developer and explorer is pleased to report new results from the ongoing step-out drill program at its 100% owned high grade APTA deposit; one of five identified target areas in the Anzá project in Colombia (Fig. 1).

Notable results to date from 17 intercepts in 7 drill holes focused on expansion drilling at the APTA deposit are highlighted below and include numerous significant intervals at high grades, including:

• 17.76 g/t Au over 5.32 metres in MAP_54 (as previously announced);
• 4.89 g/t Au over 13.9 metres in MAP_55;
• 5.00 g/t Au over 23 metres in MAP_62; and
• 4.86 g/t Au over 25.0 metres in MAP_60.

Ignacio Salazar, CEO of Orosur, said:

"I am delighted to report a strong set of step-out drilling results from our high grade APTA project. These results continue intercepting high grade gold mineralization over multiple significant intervals and have extended the mineralized zone a further 75 metres down dip, 50 metres up dip and 85 metres along strike to the north. APTA high grade gold mineralized intercepts now cover a strike extent of approximately 1.5km and depth extent of 275 metres and remains open in all directions.

There are 5 more holes drilled in APTA still pending assay results and we plan to drill up to a further 6 holes at Charrascala in the coming weeks. The new drilling planned at Charrascala seek to add an additional mineralized body in an area that is approximately 3 km north-south by 1 km east-west.

APTA and Charrascala are two of the five identified target areas in our Anzá project in Colombia.”

Drilling conducted to date supports Orosur’s geological model at APTA and recent drilling has extended the mineralized zone a further 75 metres down dip, 50 metres up dip and 85 metres along strike to the north. APTA high grade gold mineralized intercepts now cover a strike extent of approximately 1.5km and depth extent of 275 metres and remains open in all directions.

To date, Orosur has completed 16 holes (MAP_54 to MAP_69, Fig. 2) totaling 5,640.5 metres at APTA and has received assay results for 9 holes totalling approximately 3,121 metres (MAP_54 to MAP_62, Fig. 2 above). Of the nine holes, seven had notable gold intercepts (Table 1).

Drill Program Highlights

APTA’s gold mineralisation continues to be reinforced with the current drill program with MAP_54, MAP_56 and MAP-59 extending gold mineralization 75 metres down dip and 50 metres up dip. 275 metres of depth potential has now been drill defined at APTA. Gold mineralization is associated with intense silicification and faulting.

An additional broad zone of gold mineralization covering a continuous 450 metres of strike and immediately north of previous drilling has been defined. Results from two holes (MAP_60 & MAP_62) have demonstrated multiple zones of gold mineralization including 5.5g/t Au over 3.34 metres from 70 metres depth and 4.86g/t Au over 25 metres from 222 metres depth in MAP_60 and 5.09g/t Au over 5.3 metres from 60 metres depth and 5.00g/t Au over 23 metres from 217m depth in MAP_62 (Table 1, Figs 2, 3, & 4). This zone is characterized by strongly silicified breccias with disseminated sulphides like pyrite, sphalerite chalcopyrite and traces of galena.

Near Term Exploration Program

The Anzá project contains a further four high priority targets with coincident geochemical and geophysical anomalies (Fig. 1). Apart from APTA, the highest priority target, at present, is Charrascala which is located 1.5 km to the west of APTA. Charrascala is defined by an extensive coincident gold in soil and magnetic anomaly that is approximately 3 km north-south by 1 km east-west and localized along a potential north-south structure. Surface mapping and sampling combined with interrogation of geophysical data sets indicates very similar signatures to APTA.

Given the validation of APTA’s geological model with recent drilling, the last phase of this exploration campaign will focus on Charrascala with up to six planned diamond holes to drill test its potential. As a consequence, there will be a reduction of planned infill drilling at APTA, which will result in approximately 10,000 metres of drilling in total for this exploration campaign, compared to the 15,000 metres previously announced. The reduction in drilling planned for the remainder of this exploration program will allow increased investment at Charrascala, including additional geochemical work, road access, drilling platform preparation and rig displacements. Orosur is also adding surface exploration activities, including mapping and sampling, across the broader Anzá project. All permits required to complete this program, including drilling permits at Charrascala, have now been granted.

To view the full release, showing all maps and figures, please click here.

Update on Uruguay operations

The block model for San Gregorio Central (SGC) which was finalized in financial year Q2 18 showed that the mineralized structure is less economically viable at depth and to the East due to reductions in both ore grade and thickness. The Company therefore optimized the mine plan for SGC and development started and advanced during Q3 while initial production from SGC is expected at the end of Q3. In parallel, during Q3 the Company started the development on the last two deepest levels of SGW and the pre-stripping of the open pit Sobresaliente. As a consequence, the company expects higher unit cost in Q3, to be improved in Q4 when SGC and Sobresaliente are planned to be in production. A significant effort is being allocated to reduce costs and accelerate the progress of the SG East and Veta A UG projects. Orosur will provide a detailed update of the operations in the Q3 Results Report in April 2018.

Quality Control and Reporting Protocols

This initial drill program recovered HQ/HQ3 core which was logged, split in half for sampling, with the remainder stored for reference in the secure core facility at Finca El Vergel, Anzá, Antioquia, Colombia. Samples are delivered to SGS lab and ALS lab both in Medellín, Antioquia, Colombia (ISO/IEC 17025) for analysis. At the Laboratory, samples are analyzed for gold by traditional fire assay with atomic absorption finish, with those samples returning >5 g/t gold repeated using a 50g aliquot and gravimetric finish. Samples are also analyzed for multi-elements including silver, cobalt, copper and zinc by total digestion ICP at the same labs. Selected samples will also be re-assayed by metallic sieve methods using up to a 350 g aliquot, based on gold and sulfide content.

Drill program design, Quality Assurance/Quality Control ("QA/QC”) and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards, duplicates, and blanks are added at the lab as well as standards, blanks and duplicates submitted as unknowns by the Company every ten samples. Approximately 5% of sample pulps are sent to secondary laboratories for check assay.

Assays are reported as composited intervals using weighted averages, with highly enriched zones reported separately. Assays are uncut at this time. Applicable true widths are determined by ongoing investigation of the continuity and geometry of zones, and are typically expected to be 65% to 85% of the reported core lengths.

Qualified Person

The technical information related to the current assets of Orosur Mining in this announcement has been reviewed and approved by independent Mining engineer Miguel Fuentealba, a qualified person as defined by National Instrument 43-101.

About Orosur Mining Inc.

Orosur Mining Inc. (TSX: OMI; AIM: OMI) is a fully integrated gold producer, developer and explorer focused on identifying and advancing gold projects in South America. The Company operates the only producing gold mine in Uruguay (San Gregorio), and has assembled an exploration portfolio of high quality assets in Uruguay, Chile and Colombia.

The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulation ("MAR"). Upon the publication of this announcement via Regulatory Information Service, this inside information is now considered to be in the public domain. If you have any queries on this, then please contact Ignacio Salazar, Chief Executive Officer of the Company (responsible for arranging release of this announcement) on: +1 (778) 373-0100.

Forward Looking Statements

All statements, other than statements of historical fact, contained or incorporated by reference in this news release, including any information as to the future financial or operating performance of the Company, constitute "forward-looking statements" within the meaning of certain securities laws, including the "safe harbour" provisions of the Securities Act (Ontario) and the United States Private Securities Litigation Reform Act of 1995 and are based on expectations estimates and projections as of the date of this news release. There can be no assurance that such statements will prove to be accurate. Such statements are subject to significant risks and uncertainties, and actual results and future events could differ materially from those anticipated in such statements. Forward-looking statements include, without limitation success of exploration activities; permitting time lines; the failure of plant; equipment or processes to operate as anticipated; accidents; labour disputes; requirements for additional capital title disputes or claims and limitations on insurance coverage. The Company disclaims any intention or obligation to update or revise any forward looking statements whether as a result of new information, future events and such forward-looking statements, except to the extent required by applicable law.

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