Coro Mining Marimaca Exploration Update: Northwards Continuation of Mineralization Confirmed at Atahualpa
Highlighted by 120 metres at 1.09% CuT and 106 metres at 0.89% CuT
VANCOUVER, British Columbia, Feb. 07, 2019 (GLOBE NEWSWIRE) — Coro Mining Corp. (“Coro” or the “Company”) (TSX: COP) is pleased to announce an update for the Company’s Marimaca Project in the Antofagasta Region of Chile. The first 21 RC holes totalling 6,750 metres have been drilled at Atahualpa and have confirmed the northward extension of copper oxide mineralization from that previously defined at Marimaca 1-23 and La Atómica. The Marimaca deposit has now been shown to be continuous over a strike length in excess of 1,000 metres and remains open to the north. As previously announced on November 27, 2018, underground workings at Atahualpa have been sampled and mineralization is known to be present for at least a further 250 metres beyond the current drill pattern. Marimaca averages in excess of 500 metres in width, narrowing to the south, and leachable mineralization averages 50 to 200 metres in thickness.
From 6 to 84 metres, 78 metres of copper oxide mineralization averaging 0.62% CuT
Hole ATR-04 (extending to Marimaca 1-23 model area)
- From 2 to 122 metres, 120 metres of copper oxide and lesser enriched sulphide mineralization averaging 1.09% CuT
- From 54 to 116 metres, 62 metres of copper oxide and lesser mixed mineralization averaging 0.61% CuT
- From 174 to 248 metres, 74 metres of mixed and enriched copper mineralization averaging 1.06% CuT
- From 0 to 106 metres, 106 metres of copper oxide and mixed mineralization averaging 0.89% CuT
- From 50 to 106 metres, 56 metres of copper oxide and mixed mineralization averaging 1.03% CuT
Commenting on the results, Luis Tondo, CEO of Coro stated: “We are delighted that the first batch of drill results at Atahualpa, the area adjacent and to the north of Marimaca, has confirmed that the copper oxide mineralized zones extend on to the Atahualpa claims. This is an important milestone for the project because we are now demonstrating the real potential of a larger resource at Marimaca, surpassing that established in the Phase I program. As the Phase II program continues and expands, we look forward to releasing more results confirming the continued growth of the Marimaca Project.”
The Phase I drilling that established the initial Marimaca 1-23 resources and the Phase II drilling completed thus far at La Atómica and Atahualpha are detailed below in Figure 1.
Discussion of Results
Interpretation of all drilling to date shows that two styles of mineralization are present at Marimaca, as illustrated in Figure 1, namely:
- To the west, mineralization is more structurally controlled and characterised by weak to moderate north south oriented parallel fracturing cross cut by 60° east dipping, north south feeders, containing high grade brochantite rich mineralization, previously mined in the underground workings.
- To the east, the mineralization is characterised by strong north south penetrative parallel fracturing cross cut by north east oriented sub vertical feeders and is the continuation of the previously drilled Marimaca style mineralization. The two styles are separated by a dyke swarm known as the Main Dacitic Dyke (MDD) and a similar set of dykes defines the hanging wall of the Marimaca style mineralization.
Towards the west, drill holes ATR-15, 17, 18 and 19 defined the border of the Marimaca deposit, intersecting narrow low-grade copper mineralization related to a northeast system of dioritic dykes. To the east, a concealed post mineral diorite containing minor primary sulphides was intersected in hole ATR-21 and in holes previously drilled inn the north east section of the Marimaca 1-23 Claim.
The drilling has also returned some attractive primary sulphide copper grades, notably, ATR-04, 18 metres at 0.95% CuT, ATR-08, 14 metres at 0.94% CuT and ATR-10, 16 metres at 0.66% CuT. These results confirm the existence of sulphide mineralization at depth and remaining open.
The section diagram above corresponds to a cross section along the 310° direction, showing copper grades from new RC holes as well as intersected underground workings. Thickness and grades increase towards the east as they are controlled by the intersection of NS strike dipping east parallel fractures with north east trending feeders. Limits between mineralized zones are also shown. In this section the higher grades correspond chiefly to brochantite rich mineralization.
Two drill rigs are currently operating on site. With the drill rigs fully active and assaying now in progress, the Phase II program is approaching peak activity. A third RC rig and a diamond drilling will add to the overall activity, expected to peak in March 2019. The anticipated enlarged and integrated Marimaca resource estimate remains on track for completion in the third quarter of 2019. The preparation of access roads, drilling platforms and RC drilling at Tarso and Sorpresa has commenced. The Marimaca project area and exploration Phases are detailed in the Figure 3 below.
Sampling and Assay Protocol
True widths cannot be determined with the information available at this time. Coro RC holes were sampled on a 2-metre continuous basis, with dry samples riffle split on site and one quarter sent to the Andes Analytical Assay preparation laboratory in Calama and the pulps then sent to the same company laboratory in Santiago for assaying. A second quarter was stored on site for reference. Samples were prepared using the following standard protocol: drying; crushing to better than 85% passing -10#; homogenizing; splitting; pulverizing a 500-700g subsample to 95% passing -150#; and a 125g split of this sent for assaying. All samples were assayed for CuT (total copper), CuS (acid soluble copper), CuCN (cyanide soluble copper) by AAS and for acid consumption. A full QA/QC program, involving insertion of appropriate blanks, standards and duplicates was employed with acceptable results. Pulps and sample rejects are stored by Coro for future reference.
Underground samples were taken as 2 metres continuous chip channel samples in previously carefully cleaned surface walls. Both adit walls were sampled by Coro personnel. The samples were transported to the Andes Analytical Assays (“AAA”) preparation laboratory in Calama. Samples were prepared and assayed as for the drill samples. No standards, blanks or duplicates were employed. After sampling, underground workings were geologically mapped in detail following a protocol adapted from that used for drill hole logging, with emphasis on mineralization and its structural and litohologic controls.
Figure 4: Atahualpa Intersections
|ATR-01||250||26||116||90||0.44||Oxide – Mixed – Enriched|
|and||124||132||8||0.35||Primary – Enriched|
|and||68||88||20||0.37||Mixed – Enriched|
|184||204||20||0.41||Primary – Enriched|
|ATR-04||350||2||122||120||1.09||Oxide – Enriched|
Atahualpa intersections continued,
|ATR-05||450||54||116||62||0.61||Oxide – Mixed|
|including||54||84||30||0.81||Oxide – Mixed|
|and||174||248||74||1.06||Mixed – Enriched|
|including||198||248||50||1.41||Primary – Enriched|
|336||342||6||0.43||Mixed – Enriched|
|198||210||12||1.24||Primary – Enriched|
|ATR-07||400||0||106||106||0.89||Oxide – Mixed|
|including||16||46||30||1.52||Oxide – Mixed|
|including||66||106||40||1.27||Mixed – Enriched|
|and||76||102||26||1.91||Oxide – Enriched|
|134||150||16||0.21||Oxide – Mixed|
Atahualpa intersections continued,
|and||118||138||20||0.40||Mixed – Enriched|
|246||258||12||0.49||Primary – Mixed|
|ATR-15||200||No Significant Results|
|ATR-22||350||110||134||24||0.55||Oxide – Mixed|
|including||112||130||18||0.65||Oxide – Mixed|
|and||170||178||8||0.50||Enriched – Mixed|
Figure 5: Atahualpa Drill Collars
The technical information in this news release, including the information that relates to geology, drilling and mineralization of the Marimaca Phase I and II exploration program was prepared under the supervision of, or has been reviewed by Sergio Rivera, Vice President of Exploration, Coro Mining Corp, a geologist with more than 36 years of experience and a member of the Colegio de Geologos de Chile and of the Institute of Mining Engineers of Chile, and who is the Qualified Person for the purposes of NI 43-101 responsible for the design and execution of the drilling program.
Forward Looking Statements
This news release includes certain “forward-looking statements” under applicable Canadian securities legislation. These statements relate to future events or the Company’s future performance, business prospects or opportunities. Forward-looking statements include, but are not limited to, statements regarding the future development and exploration potential of the Marimaca Project. Actual future results may differ materially. There can be no assurance that such statements will prove to be accurate, and actual results and future events could differ materially from those anticipated in such statements. Forward-looking statements reflect the beliefs, opinions and projections on the date the statements are made and are based upon a number of assumptions and estimates that, while considered reasonable by Coro, are inherently subject to significant business, economic, competitive, political and social uncertainties and contingencies. Many factors, both known and unknown, could cause actual results, performance or achievements to be materially different from the results, performance or achievements that are or may be expressed or implied by such forward-looking statements and the parties have made assumptions and estimates based on or related to many of these factors. Such factors include, without limitation: the inherent risks involved in the mining, exploration and development of mineral properties, the uncertainties involved in interpreting drilling results and other geological data, fluctuating metal prices, the possibility of project delays or cost overruns or unanticipated excessive operating costs and expenses, uncertainties related to the necessity of financing, the availability of and costs of financing needed in the future as well as those factors disclosed in the Company’s documents filed from time to time with the securities regulators in the Provinces of British Columbia, Alberta, Saskatchewan, Manitoba, Ontario, New Brunswick, Nova Scotia, Prince Edward Island and Newfoundland and Labrador. Accordingly, readers should not place undue reliance on forward-looking statements. Coro undertakes no obligation to update publicly or otherwise revise any forward-looking statements contained herein whether as a result of new information or future events or otherwise, except as may be required by law.
Photos accompanying this announcement are available at :