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Metminco Limited (MNC)


Tuesday 31 July, 2018

Metminco Limited

Tesorito Drilling Update

RNS Number : 2721W
Metminco Limited
31 July 2018


31 July 2018





This announcement is an abridged version of the announcement and does not include schematics.  For the full announcement, please refer to the Company's website at



·     Assays from hole TS_DH_04 include:

179.8m @ 0.7g/t Au from surface

including 21.8m @ 1.03g/t Au from surface

and 90.0m @ 0.83g/t Au from 26.8m


·     Assays from TS_DH_05 include (partial results)

212.7m @ 0.39 g/t Au from surface

including 32.2m @ 0.77 g/t Au from surface

and 15.5m @ 0.61 g/t Au from 112.6m


·     Assays expected for remainder of TS_DH_05; and 06 and 07 in August 2018.


·     This and previous drilling confirms the gold mineralisation (over 0.5 g/t Au) is extensive in area (400m x 180m); is open laterally to the north-northeast, east-southeast and at depth.

·     Intensive phyllic alteration intercepted in TS_DH_05, with increasing base metal mineralisation and potassic alteration with depth, similar trends seen in most holes reported to date, suggest the central zone of the Tesorito porphyry system is located primarily beneath the existing Induced Polarisation ("IP") anomaly.

Executive Chairman Mr. Kevin Wilson said of the results "The intensity of hydrothermal alteration seen at Tesorito together with prolific gold mineralisation already recognised in the Quinchia district and elsewhere in the Cauca belt suggests this to be major mineralising system which offers great potential for exploration success. In the classic porphyry model, the mineralisation seen at Tesorito could be the gold cap to base metal mineralisation at depth."



Metminco Limited (ASX & AIM: MNC) ("Metminco" or the "Company") is pleased to announce the results of the assays received to date for the first two diamond  drill holes (partial results received for the TS_DH_05) from its Tesorito gold prospect in the Quinchia district, Colombia (Table 1). The Quinchia district occurs in the mid Cauca belt, host to large gold deposits such as La Colosa (28Mozs) and Quebradona (21Mozs) (Figure 1).


The Tesorito prospect occurs 800m south east of the Company's Miraflores deposit (0.88Moz gold Resource) and approximately 3km south east of the Company's Dosquebradas deposit (0.92Moz gold Resource estimated under NI 43-101 - see announcement dated 7 March 2016). It is also located approximately 2km north of the large undrilled Chuscal porphyry target.


The Company's current 1,500m diamond drilling program, is designed to confirm and expand the gold mineral system intersected in drilling by a previous operator. This included hole TS_DH_02 which reported 384m @ 1.1g/t Au from surface to end-of-hole (Table 1, refer announcement 7 March 2016). The program will also test a previously undrilled geophysical anomaly located approximately 300m to the northwest of TS_DH_02 (Figure 2).


Figure 1. The Cauca Belt of Colombia, with the location of Metminco's Miraflores resource at Quinchia, which is adjacent to Tesorito.

Although early in its exploration history, Metminco believes the mineralisation at Tesorito represents the gold-rich cap of a deeper base-metal rich porphyry system. This is supported by the phyllic alteration and increasing base-metal content and igneous activity with depth seen in several holes.

The intensity of hydrothermal alteration seen at Tesorito together with prolific gold mineralisation already recognised in the Quinchia district and elsewhere in the Cauca belt suggests this to be major mineralising system which offers great potential for exploration success.

Next Steps

·     receipt of assays from the final 2 diamond holes and remainder of TS_DH_05

·   undertake a detailed logging program on the recently acquired drill core supported by mineralogical analysis to determine vectors for focusing next stage exploration drilling.



The program is comprised of four moderate-depth diamond drill holes (Figures 2, 3, 4, 5 and 6) with results summarised in Table 1 below.

Drill Hole


TS_DH_01 Previously drilled and reported

266.5m @ 0.46 g/t Au, 0.58 g/t Ag and 0.034% Cu from 83.5m

TS_DH_02 Previously drilled and reported

384.0m @ 1.01 g/t Au, 0.86 g/t Ag and 0.084% Cu from 16.0m

including 32.5m @ 1.34 g/t Au, 0.81 g/t Ag and 0.094 % Cu from 48.8m

and 156.6m @ 1.28 g/t Au, 0.93 g/t Ag and 0.085% Cu from 88.3m

and 3.95m @ 3.43 g/t Au, 6.67 g/t Ag and 2.63% Cu from 390.8m

TS_DH_03 Previously drilled and reported

254.9m @ 0.51 g/t Au, 0.67 g/t Ag and 0.052% Cu from 9.3m


179.8m @ 0.70 g/t Au, 0.91 g/t Ag and 0.064% Cu from 3m

including 21.8m @ 1.03 g/t Au, 0.92 g/t Ag and 0.077% Cu from 3m

and 90.0m @ 0.83 g/t Au, 1.05 g/t Ag and 0.078% Cu from 26.8m

2m @ 17.95 g/t Ag, 1.99 g/t W and >1% Zn from 343.0m

TS_DH_05 Full results pending

212.72m @ 0.39 g/t Au, 0.72 g/t Ag and 0.053% Cu from 4.7m

including 32.2m @ 0.77 g/t Au, 0.61 g/t Ag and 0.072 & Cu from 4.7m

and 15.5m @ 0.61 g/t Au, 0.83 g/t Ag and 0.063% Cu from 112.6m

and 3.95m @ 0.75 g/t Au, 3.82 g/t Ag, 0.139% Cu, 52.7 ppm Pb, and 168.0 ppm Zn from 211.8m


Table 1. Summary assay results from all drill holes to date at Tesorito.

From the results received to date from Tesorito and the previous historical drilling:

·     all 5 holes drilled into have returned gold mineralisation from a multi-phase porphyritic intrusive complex

·    the gold mineralisation is extensive in area, and occupies at least 400m x 180m and is open laterally to  the north-northeast and east-southeast

·     higher grade gold areas of over 1 g/t Au occur within the broader mineralisation envelope of approximately 0.5 g/t Au

·     depth of porphyry mineralisation has been seen up to 380m below surface (TS_DH_02) and the presence of garnets in previous and present drill core are indicative of a deep vertical plumbing system

·     intense phyllic alteration mapped by the significant IP anomaly located to the west of the known Tesorito porphyry and seen in the surface mapping and sampling and the drill core, suggests a major hydrothermal system exists approximately 200-300m to the north west of the locus of the Tesorito prospect

·     phyllic alteration is generally indicative of the upper and lateral zones of a porphyry system. There is a general increased presence of A-, B-, and M-type veining down-hole in holes drilled towards the IP anomaly. Furthermore, initial logging indicates a general increase in the presence of potassic alteration in the same direction along with an increasing presence of base metals with depth. These factors are all pointing to the central zone of the Tesorito porphyry system being located primarily beneath the IP anomaly with porphyry-associated mineralisation extending laterally upwards from it

·     the localised controls on higher order gold mineralisation traversed by TS_DH_02 and TS_DH_04 require further investigation to determine their distinct characteristics, and their likelihood of being repeated within the porphyry complex


Figure 2. Plan of Tesorito drilling, showing location of drill traces and IP anomaly.  Section B-B' is presented as Figure 4 (below), the other sections are appended with Table 1.

Details of the Program

TS_DH_04 was collared from the same platform that was used to drill TS_DH_02 and was drilled at a steeper angle (70 degrees) to test the well-mineralised stockwork veining developed in porphyritic sub-volcanic (shallow depth) dacitic and andesitic intrusives.

TS_DH_05 was drilled to test for lateral and upward extensions of the well-mineralised stockwork veining traversed by drill hole TS_DH_02. In addition, TS_DH_05 was designed to test the nature and extent of the mineralisation beneath the >100 ppb gold in soil geochemical anomaly and the high grade (up to 2m at 6.6 g/t Au - refer announcement 27 March 2018, Appendix D) gold assays returned from sampling in trenches.

TS_DH_06 was drilled principally to test the nature and extent of what has caused the strong IP geophysical response over a north-northeast trending 1,000m long x 300m wide zone developed to the northwest of the gold in soil geochemical anomaly. It was designed to traverse the zone which was modelled to have the strongest coincident chargeability and conductivity readings.

TS_DH_07 was designed to test the three-dimensional geometry of the higher-grade mineralisation returned from TS_DH_02 and any mappable controls which could assist in determining the extent and frequency of the higher-grade zones within the porphyry complex.

Details of the drill results

TS_DH_04 has confirmed the continuation at depth of the gold mineralisation beneath TS_DH_02 over similar intervals and grade for the first 180m, with downhole intercept of 179.8m @ 0.70 g/t Au, 0.91 g/t Ag and 0.064% Cu, including 21.8m @ 1.03 g/t Au, 0.92 g/t Ag and 0.077% Cu and 90.0m @ 0.83 g/t Au, 1.05 g/t Ag and 0.078% Cu.  The gold mineralisation is associated with stockwork veining exhibiting A-, B- and M-type veins that typify porphyry-style mineralisation as shown in Figure 3. 

The drill hole then passed through an alternating sequence of basement blocks separated by relatively narrow intrusive porphyritic dacitic and andesitic dykes and was terminated in basement rocks at 400m. The basement blocks comprised contact metamorphosed arkosic sandstones likely to be part of the Tertiary-aged Amaga Formation and deformed fine-grained basaltic lavas of the Cretaceous Barroso Formation.

Of further interest, TS_DH_04 intercepted a zone of high strain within basement (basalt) from 343m to 345m that returned assays of 17.95 g/t Ag, 1.99 g/t W and >1% Zn.  A discreet, narrow high-grade intercept returned 3.43 g/t Au, 6.67 g/t Ag and 2.63% Cu from a 3.95m sample intercepted from near the base (390.8m to 391.5m depth) of hole TS_DH_02 within porphyritic dacite.  Further work is warranted to better understand the significance, nature and extent of these high-grade polymetallic mineralised intercepts in the context of the porphyry system.

TS_DH_05 has confirmed the presence of stockwork veining developed in porphyritic sub volcanic dacitic and andesitic intrusives from 0 to 293m depth down hole, after which it passed into a less veined but increasingly sericite-altered porphyry for the remainder of the hole, which was terminated at 390.5 m. TS_DH_05 returned mineralised intercepts of 212.7m @ 0.39 g/t Au, 0.72 g/t Ag and 0.053% Cu from 4.7m, with the assay results still pending for the remaining 174m to end of hole. The extent and tenor of the mineralisation, as determined from assay results received to date, closely resembles the results obtained from TS_DH_01 located some approximately 100m towards the north east.


Figure 3:  Core photographs showing porphyry with veinlet styles.

  1. TS_DH_04 (80.7m) Medium grained andesite porphyry, with A quartz veins and potassic feldspar halos.
  2. TS_DH_04 (87.2m) Medium and coarse-grained andesite porphyry, with intrusive breccia and A vein.
  3. TS_DH_07 (153.5m) Fine grained andesite porphyry, with B quartz veins.

       4. TS_DH_07 (200.3m) Medium grained andesite porphyry, with intrusive breccia


Figure 4. Cross section B-B' from Figure 2 showing TS_DH_04; TS_DH_05; TS_DH_07 (in progress) and the IP chargeability anomaly.

The last two samples for which results have been received from TS_DH_05 returned assays of 3.95m at 0.75 g/t Au, 3.82 g/t Ag, 0.139% Cu, 52.7 ppm Pb, and 168.0 ppm Zn from 211.8m to 215.5m.  This suggests an elevated base metal assemblage which supports the observation from holes TS_DH_02 and TS_DH_04 of an increase in base metals with depth and closer proximity to the IP geophysical anomaly.

TS_DH_06 returned core exhibiting similar lithologies to those encountered in the lower hundred metres of TS_DH_05, comprising increasingly sericite-altered porphyritic dacitic and andesitic intrusive rocks. The intense sericite alteration, commonly referred to as phyllic alteration, is an important component of porphyry-style precious and base metal systems and is considered the likely cause of the strong IP geophysical response. The fact that this significantly intense anomaly extends for nearly 1km along the western limits of the porphyritic intrusive complex is indicative of a large zone of intensive phyllic alteration likely to be associated with a porphyry-style hydrothermal system of significant scale and intensity. Assay results from TS_DH_06 have not been received at the time of this release.

TS_DH_07 is in the process of being completed at the time of this release and samples are being prepared for submission to the laboratory. The rocks encountered are logged as well-veined porphyry similar to that encountered in TS_DH_02 and the upper parts of TS_DH_04 (Figure 2).

Results from the deeper part of TS_DH_05 as well as 06 and 07 are expected during August 2018.

For further enquiries contact:

Kevin Wilson

Executive Chairman Metminco Limited;  

[email protected] ;

+61 409 942 355


The Glossary of Terms is included as Appendix F in the Attachment Table 1.  




For further information, please contact:




Kevin Wilson


+61 409 942 355







RFC Ambrian






Andrew Thomson / Alena Broesder


Office:  +  61 2 9250 0000




United Kingdom



Charlie Cryer


Office:  + 44 20 3440 6800








United Kingdom



Gordon Poole / Nick Hennis


Office:  + 44 20 3757 4997





Market Abuse Regulation (MAR) Disclosure

The information communicated in this announcement includes inside information for the purposes of Article 7 of Regulation 596/2014.

Forward Looking Statement

All statements other than statements of historical fact included in this announcement including, without limitation, statements regarding future plans and objectives of Metminco are forward-looking statements.  When used in this announcement, forward-looking statements can be identified by words such as ''anticipate", "believe", "could", "estimate", "expect", "future", "intend", "may", "opportunity", "plan", "potential", "project", "seek", "will" and other similar words that involve risks and uncertainties.

These statements are based on an assessment of present economic and operating conditions, and on a number of assumptions regarding future events and actions that, as at the date of this announcement, are expected to take place.  Such forward-looking statements are not guarantees of future performance and involve known and unknown risks, uncertainties, assumptions and other important factors, many of which are beyond the control of the Company, its directors and management of Metminco that could cause Metminco's actual results to differ materially from the results expressed or anticipated in these statements.

The Company cannot and does not give any assurance that the results, performance or achievements expressed or implied by the forward-looking statements contained in this announcement will actually occur and investors are cautioned not to place undue reliance on these forward-looking statements. Metminco does not undertake to update or revise forward-looking statements, or to publish prospective financial information in the future, regardless of whether new information, future events or any other factors affect the information contained in this announcement, except where required by applicable law and stock exchange listing.


The technical information contained in this presentation that relates to exploration results (excluding those pertaining to Mineral Resources and Reserves) is based on information compiled by Mr Gavin Daneel, who is a Member of the Australasian Institute of Mining and Metallurgy and who is an independent Consulting Geologist.  Mr Daneel has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration, and to the activity which he is undertaking, to qualify as a Competent Person as defined in the 2012 Edition of the 'Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves' and to qualify as a Qualified Person for the purposes of the AIM Rules for Companies.  Mr Daneel consents to the inclusion in the release of the matters based on the information he has compiled in the form and context in which it appears.

The Company is not aware of any new information or data that materially affects the information included in this announcement.

This information is provided by RNS, the news service of the London Stock Exchange. RNS is approved by the Financial Conduct Authority to act as a Primary Information Provider in the United Kingdom. Terms and conditions relating to the use and distribution of this information may apply. For further information, please contact [email protected] or visit

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