TORONTO, Feb. 03, 2020 (GLOBE NEWSWIRE) -- Gran Colombia Gold Corp. (TSX: GCM; OTCQX: TPRFF) announced today additional higher-grade gold intercepts over broad widths from the final eight diamond drill holes (3,744 meters) drilled in the Marmato Deeps Zone (“MDZ”) completing the 2019 Phase 2 infill drilling program (the “2019 drilling campaign”) at its Marmato Project in Caldas, Colombia. The 2019 drilling campaign was split into two phases, of which the results of the Phase 1 drilling campaign were included in the updated Mineral Resource estimate with an effective date of July 31, 2019 and the preliminary economic assessment (“PEA”) for Marmato, both of which were included in a technical report filed on SEDAR on November 28, 2019. The subsequent Phase 2 infill drilling, above the 600 meter level, was designed to provide enough tonnes and grade in the Measured and Indicated mineral resource categories within the Main Zone (“MZ”) to support the prefeasibility study (“PFS”) which is currently being carried out and is expected to be finalized by mid-2020.
High-grade mineralization was also encountered in a new zone (“NZ”) in the footwall of the MDZ in hole MT-IU-050 and is anticipated to be accretive to overall global resource growth as this mineralization lies either outside the boundary of the current mineral resource estimate block model for the MZ or in areas that were previously estimated to be below the cut-off grade due to lack of information.
Serafino Iacono, Executive Chairman of Gran Colombia, commented, “Our 2019 Phase 2 drilling campaign has generated additional exciting results which have further increased our confidence in the geological model and continues to demonstrate an improvement of grades in the MZ below the 900 meter level versus the mineral resource block model associated with the PEA. In addition, the discovery of a potential new high-grade zone opens a new scenario for potential resource growth. All in all, we remain very encouraged by the progress we are making in the evaluation of the underground mining expansion opportunity at our Marmato Project."
The 2019 drilling campaign started in March and was completed in late November with three contractor diamond drill rigs, one of which was added to the Phase 2 drilling campaign in early September, operating from four purpose-built underground drill stations. The two drilling campaigns comprise a total of 30 drill holes totaling approximately 16,299 meters, of which 4,600 meters were completed in seven drill holes in Phase 1 and 11,699 meters were completed in 23 drill holes in Phase 2.
The Company plans to drill up to 15,000 meters in 2020 commencing toward the end of February. Approximately 10,000 meters of infill drilling is designed to convert Inferred mineral resources to the Indicated category and to add additional mineral resources by stepping out along the southeast extension of the MZ. Another approximately 5,000 meters of exploration drilling will focus on broad mineralized zone targets outside the MDZ.
Intersections with high gold grades generated from the last eight drill holes of Phase 2 drilling reported herein (MT-IU-046 to MT-IU-052 and MT-IU-054), include:
- Drill hole MT-IU-050 which intersected 54.42 m at 3.65 g/t Au and 4.3 g/t Ag from 246.75 m to 301.17 m, 51.80 m at 3.0 g/t Au and 6.0 g/t Ag from 379.3 m to 431.10 m, and 41.35 m at 4.14 g/t Au and 4.34 g/t Ag from 449.0 m to 490.35m; all these intersections are associated with the MZ.
- Drill hole MT-IU-050 also intersected 76.75 m at 3.12 g/t Au and 1.9 g/t Ag from 538.25 m to 615.00 m, which is the intersection associated with the NZ.
- Drill hole MT-IU-051 which intersected 75.83 m at 4.03 g/t Au and 5.5 g/t Ag from 248.00 m to 323.83 m.
- Drill hole MT-IU-054 which intersected 66.35 m at 3.05 g/t Au and 3.9 g/t Ag from 358.00 m to 424.35 m.
The style of mineralization for the intersection associated with the NZ is the same as the MZ and is characterized by very narrow veinlets of quartz-pyrrhotite-bismuth tellurides-free gold with minor amounts of pyrite and chalcopyrite rimmed by a narrow halo of sodic-calcic alteration.
Key Highlights and Intercepts from Phase 2 drilling
- The high-grade mineralization intercepted in drill hole MT-IU-050, outside the boundary of the current mineral resource estimate block model for the MZ, may represent a new zone (NZ) or a branch off the MZ. Further drilling in this area is required and is planned as part of the 2020 drilling program;
- The drill intercepts (MT-IU-050, MT-IU-051 and MT-IU-054) from Phase 2 drilling continue to demonstrate a further improvement of grades in the MZ below the 900 meter level versus the mineral resource block model associated with the PEA;
- The results from Phase 2 infill drilling continue to impress both in terms of grades and widths and will undoubtedly lead to an important resource growth coupled with a greater flexibility for mining;
- Most of the drill holes of Phase 2 reported herein end within the low-grade shell with the result that the MDZ is open on the east side. This is due to the location of underground drill stations above and close to the steeply plunging low grade shell. The holes achieved their objective of fully cutting the high grade MZ.
The following table is a list of significant intersections from the last eight drill holes (MT-IU-046 to MT-IU-054) of Phase 2 drilling reported in this release that, combined with the fourteen drill holes included in the press release issued on November 15th, 2019, will support the PFS level resources and reserves statement:
| Hole ID | From (m) | To (m) | Width (m) | Au Grade
(g/t) | Ag Grade
(g/t) | Grade-
Width
Au (g/t
*m) | Zone |
| MT-IU-032 | 334.46 | 682.75 | 348.29 | 1.53 | 3.1 | 534 | Deeps |
| including | 334.46 | 391.03 | 56.57 | 1.54 | 4.9 | 87 | Deeps |
| including | 391.03 | 416.08 | 25.05 | 2.55 | 5.9 | 64 | Deeps |
| including | 438.32 | 463.05 | 24.73 | 2.03 | 4.1 | 50 | Deeps |
| including | 495.00 | 524.45 | 29.45 | 1.76 | 5.2 | 52 | Deeps |
| including | 566.75 | 601.40 | 34.65 | 2.31 | 2.1 | 80 | Deeps |
| including | 623.40 | 646.10 | 22.70 | 2.21 | 1.4 | 50 | Deeps |
| including | 663.10 | 682.75 | 19.65 | 2.56 | 1.2 | 50 | Deeps |
| MT-IU-033 | 287.35 | 707.25 | 419.90 | 1.84 | 2.4 | 774 | Deeps |
| including | 287.35 | 334.00 | 46.65 | 2.31 | 7.1 | 108 | Deeps |
| including | 402.55 | 447.55 | 45.00 | 3.37 | 2.8 | 151 | Deeps |
| including | 456.60 | 494.00 | 37.40 | 2.72 | 2.2 | 102 | Deeps |
| including | 580.80 | 612.00 | 31.20 | 3.16 | 1.8 | 99 | Deeps |
| including | 634.30 | 652.80 | 18.50 | 3.00 | 2.1 | 55 | Deeps |
| MT-IU-034 | 314.05 | 501.00 | 186.95 | 1.34 | 2.3 | 251 | Deeps |
| including | 419.65 | 465.75 | 46.10 | 2.58 | 2.7 | 119 | Deeps |
| MT-IU-035 | 149.10 | 305.73 | 156.63 | 1.27 | 3.5 | 199 | Deeps |
| including | 177.05 | 199.95 | 22.90 | 2.55 | 4.2 | 58 | Deeps |
| MT-IU-036 | 365.25 | 670.60 | 305.35 | 2.74 | 2.9 | 836 | Deeps |
| including | 365.25 | 429.95 | 64.70 | 4.66 | 6.4 | 301 | Deeps |
| including | 469.00 | 490.60 | 21.60 | 3.55 | 2.4 | 77 | Deeps |
| including | 531.10 | 670.60 | 139.50 | 2.48 | 2.0 | 346 | Deeps |
| MT-IU-037 | 208.93 | 326.35 | 117.42 | 1.82 | 2.8 | 214 | Deeps |
| including | 208.93 | 255.85 | 46.92 | 2.53 | 2.1 | 119 | Deeps |
| including | 286.90 | 310.25 | 23.35 | 2.16 | 4.6 | 50 | Deeps |
| MT-IU-038 | 255.25 | 501.25 | 246.00 | 2.03 | 3.0 | 499 | Deeps |
| including | 280.30 | 300.15 | 19.85 | 3.19 | 3.5 | 63 | Deeps |
| including | 334.70 | 404.05 | 69.35 | 3.16 | 4.0 | 219 | Deeps |
| MT-IU-039 | 204.35 | 356.20 | 151.85 | 1.78 | 3.1 | 271 | Deeps |
| including | 218.50 | 237.00 | 18.50 | 2.70 | 5.5 | 50 | Deeps |
| including | 253.05 | 294.70 | 41.65 | 2.50 | 3.1 | 104 | Deeps |
| including | 314.45 | 332.30 | 17.85 | 2.09 | 4.2 | 37 | Deeps |
| MT-IU-040 | 186.80 | 337.65 | 150.85 | 2.00 | 4.4 | 302 | Deeps |
| including | 224.60 | 260.45 | 35.85 | 3.40 | 9.3 | 122 | Deeps |
| including | 260.45 | 295.30 | 34.85 | 2.56 | 2.7 | 89 | Deeps |
| MT-IU-041 | 189.07 | 452.70 | 263.63 | 2.84 | 4.9 | 748 | Deeps |
| including | 226.94 | 401.90 | 174.96 | 3.86 | 6.0 | 675 | Deeps |
| including | 226.94 | 300.57 | 73.63 | 5.72 | 8.8 | 421 | Deeps |
| including | 300.57 | 333.25 | 32.68 | 1.46 | 4.5 | 48 | Deeps |
| including | 333.25 | 401.90 | 68.65 | 3.00 | 3.9 | 206 | Deeps |
| MT-IU-042 | 286.75 | 379.20 | 92.45 | 1.00 | 1.7 | 92 | Deeps |
| MT-IU-043 | NSI | | | | | | |
| MT-IU-044 | 229.88 | 501.30 | 271.42 | 1.04 | 1.8 | 282 | Deeps |
| including | 421.50 | 434.70 | 13.20 | 2.73 | 2.0 | 36 | Deeps |
| including | 467.20 | 484.45 | 17.25 | 2.80 | 2.9 | 48 | Deeps |
| MT-IU-045 | 195.25 | 607.15 | 411.90 | 2.06 | 4.8 | 849 | Deeps |
| including | 230.30 | 302.00 | 71.70 | 3.50 | 5.3 | 251 | Deeps |
| including | 420.10 | 504.85 | 84.75 | 3.21 | 8.7 | 272 | Deeps |
| including | 563.50 | 607.15 | 43.65 | 1.92 | 2.3 | 84 | Deeps |
| MT-IU-046 | 150.70 | 220.15 | 69.45 | 1.89 | 4.5 | 131 | Deeps |
| including | 191.25 | 220.15 | 28.90 | 2.81 | 4.4 | 81 | Deeps |
| MT-IU-047 | NSI | | | | | | |
| MT-IU-048 | 115.90 | 486.55 | 370.65 | 1.35 | 2.8 | 500 | Deeps |
| including | 152.85 | 206.00 | 53.15 | 2.19 | 6.2 | 116 | Deeps |
| including | 288.86 | 327.70 | 38.84 | 1.91 | 3.3 | 74 | Deeps |
| including | 414.00 | 453.00 | 39.00 | 2.39 | 2.4 | 93 | Deeps |
| MT-IU-049 | 132.15 | 324.25 | 192.10 | 1.51 | 4.7 | 291 | Deeps |
| including | 162.15 | 206.10 | 43.95 | 2.69 | 8.3 | 118 | Deeps |
| including | 214.41 | 232.30 | 17.89 | 2.76 | 3.6 | 49 | Deeps |
| including | 254.15 | 276.45 | 22.30 | 2.13 | 6.4 | 48 | Deeps |
| MT-IU-050 | 226.75 | 696.25 | 469.50 | 2.29 | 3.2 | 1075 | Deeps |
| including | 246.75 | 301.17 | 54.42 | 3.65 | 4.3 | 199 | Deeps |
| including | 379.30 | 431.10 | 51.80 | 3.00 | 6.0 | 155 | Deeps |
| including | 449.00 | 490.35 | 41.35 | 4.14 | 4.3 | 171 | Deeps |
| including | 538.25 | 615.00 | 76.75 | 3.12 | 1.9 | 239 | Deeps |
| MT-IU-051 | 188.40 | 351.70 | 163.30 | 2.81 | 5.2 | 459 | Deeps |
| including | 205.50 | 233.05 | 27.55 | 2.63 | 7.0 | 72 | Deeps |
| including | 248.00 | 323.83 | 75.83 | 4.03 | 5.5 | 306 | Deeps |
| including | 333.15 | 351.70 | 18.55 | 2.53 | 3.3 | 47 | Deeps |
| MT-IU-052 | 271.60 | 429.37 | 157.77 | 2.14 | 3.3 | 337 | Deeps |
| including | 271.60 | 297.40 | 25.80 | 2.57 | 5.5 | 66 | Deeps |
| including | 310.30 | 375.20 | 64.90 | 2.76 | 3.9 | 179 | Deeps |
| MT-IU-053A | Results pending | | | | | | |
| MT-IU-054 | 260.10 | 424.35 | 164.25 | 2.58 | 2.9 | 424 | Deeps |
| including | 260.10 | 322.75 | 62.65 | 2.91 | 2.0 | 182 | Deeps |
| including | 358.00 | 424.35 | 66.35 | 3.05 | 3.9 | 202 | Deeps |
All are underground drill holes. They were drilled at -38 to -74 degrees from the horizontal, and the intersection lengths do not represent true widths. Sample lengths are on average 1.50 meters long but may be varied for geological and recovery factors. Intersections were calculated using a cut-off grade of 0.5 g/t gold, and no more than 5.0 m of continuous internal dilution for intervals up to 50 m, no more than 10 m of continuous internal dilution for intervals of 50-200 m, and no more than 20 m of continuous internal dilution for intervals greater than 201 m. Gold grades were capped at 13.0 g/t gold which affects 14 samples of a total of 1960 samples. Intervals greater than or equal to 1.0 g/t are reported. NSI means no significant intervals. Grade-width is calculated as the width of the drill intersection in meters multiplied by the Au grade in g/t.
Please refer also to the attached illustrative images in Attachment 1 showing a longitudinal section of the higher-grade MZ zone at a cut-off grade of 1.7 g/t Au and Attachment 2 showing a cross-section of the intersection of drill hole MT-IU-050 outside the current mineral resources model for the MZ.
Qualified Person
Dr. Stewart D. Redwood, PhD, FIMMM, Senior Consulting Geologist to the Company, is a qualified person as defined by National Instrument 43-101 – Standards of Disclosure or Mineral Projects and prepared or reviewed the preparation of the scientific and technical information in this press release. Verification included a review of the quality assurance and quality control samples, and review of the applicable assay databases and assay certificates.
Quality Assurance and Quality Control
The Marmato Project core samples were prepared by SGS Laboratories Ltd (ISO 9001:2008) at their laboratory in Medellin, and assayed in their laboratory in Segovia, Colombia. Gold was assayed by 30 g fire assay with atomic absorption spectrophotometer (“AAS”) finish. Samples over 10.0 g/t gold were re-assayed by 30 g fire assay with gravimetric finish. Silver was assayed by aqua regia digestion and AAS finish. Blank, standard and duplicate samples were routinely inserted for quality assurance and quality control.