- Early prospecting started in the region.
- Coniagas Mines formed the Quebec Sturgeon River Gold Mines.
- Quebec Sturgeon River Gold Mine commenced shaft sinking on the No. 3 Quartz Vein, U/G development, producing 45 tonnes per day in 1936 - operations suspended in 1942 (wartime restrictions imposed).
- By 1942, shaft reached 680M, lateral work below 565M production level showed expanding picture for both ore veins and grade.
- Brenbar operation (adjacent to the Quebec Sturgeon River Gold Mine) extracted 150 tonnes @ 48.7 g/t gold over 65cm width, 26m strike length, stockpiles ore in 45 gallon drums (minor processing).
- Jupiter Minerals Mine and Holdings purchased Quebec Sturgeon River Gold Mines.
- completed geological mapping, magnetic/EM surveys, soil sampling, prospecting of anomalies.
- Discovered discontinuous shear zones with sphalerite-chalcopyrite-galena, up to 16m wide.
- No further work was completed.
- Jupiter changed name to Phoenix Gold Mines Ltd. - Coniagas held 5% equity, purchased by Quebec Sturgeon River Gold Mine in 1983.
- Phoenix Gold Mines extracted 7 tonne bulk sample for testing, higher grade ore could effectively BE sorted using mechanical colorimetry.
- 1984-1986, Phoenix re-mapped parts of property, completed geophysics, extensive trenching, carried out minor bulk sampling of surface material and diamond drilling
- In 1984, Phoenix targeted a possible southwest extension of vein systems developed in the former Quebec Sturgeon River Gold Mine - Drilling yielded few encouraging results.
- Phoenix then targeted areas outside of the mine area, discovered over 100 potentially GOLD-quartz veins which were subsequently trenched, sampled and analyzed.
- Phoenix recommended follow up diamond drilling on the 85-M1, A-9, A-11R, 85-A2, A2, A4 and A5-A6 quartz veins, all located what was known as the Tehya-Loki-Makwa sector by pre-2018 LAURION.
- Placer Dome optioned the property.
- completed re-evaluation, line cutting and diamond drilling - 4,460M (of BQ) core drilled in 28 holes
- Best results included 5 holes which graded 4.80 g/t gold 1m to 18.51 g/t gold over 1m
- Placer Dome subsequently returned property to Phoenix due to budgetary restrains.
- No historical data for some of drill hole collar locations, reference made to a grid, but there are no data or reference map available.
St. Andrew Goldfields Ltd., acquired the Quebec Sturgeon River Gold Mine property from Phoenix Gold Mines Ltd, primarily for Phoenix’s Timmins mining claims/properties, with no analysis or review of the Quebec Sturgeon River Gold Mine. Subsequently, the Quebec Sturgeon River Gold Mine asset was forgotten and sat dormant.
Roxmark Mines Ltd. processed 4,545 tonnes all from one single side (based easy access) of the existing Quebec Sturgeon River Gold Mine waste rock stockpile on the property.
St. Andrew Goldfields Ltd. deciding that the Quebec Sturgeon River Gold Mine was a non-core asset due to primarily to its location, and it being non-proximal its key operating mines.
The following is a description of exploration work completed by LAURION Mineral Exploration Inc. on the Ishkoday property from 2007 to 2014.
LAURION Mineral Exploration Inc., acquired the Ishkoday from St. Andrew Goldfields Ltd., and completed an independent environmental due diligence report. The report found the historic waste stockpile and tailings located on Ishkoday from the former Quebec Sturgeon River Gold Mine (1936-1942) to be non-acid generating and fairly benign.
LAURION collected a total of 14 selected grab samples during a preliminary project visit. Caracle Creek International Consulting Inc., completed a channel sampling program composed of 50 channel samples on the NW steeply dipping Marge gold-quartz vein over an identified strike length of approximately 365m. A NI 43-101 Technical Report was also completed for the Quebec Sturgeon River Mine Claim Block and was filed on SEDAR.
LAURION retained GeoVector in order to design the 2010 Ishkoday exploration program. Sampling by GeoVector of surface showings from the #3 gold-quartz vein at the former site of the Quebec Sturgeon River Gold Mine returned 95 g/t gold and 51.6 g/t gold over a 30cm vein width, confirming the historically reported higher gold grade nature of this vein at surface. In addition, two samples of the adjacent host rock over approximately 50cm width returned values of 1.35 g/t gold and 1.16 g/t gold, indicating that the host rock may well carry significant gold grades. Some165m S of the Quebec Sturgeon River Gold Mine shaft, 2 samples taken from the #3B quartz vein returned values of 34.6 g/t gold and 25.3 g/t gold.
GeoVector completed a 5-hole diamond drill program totalling 353m on the Marge gold-quartz vein which was designed to intersect the vein at right angles over a 150m strike length.
GeoVector also completed a project wide mapping and sampling program, which resulted in the discovery of two new higher grade gold mineralized zones. In total, 100 surface selected surface grab samples were collected at the Tala mineralization trend ('Tala') and 92 samples on the Asha mineralization trend ('Asha'). The first discovery zone at Tala, is located west of the Quebec Sturgeon River Gold Mine area and appears to be on strike and E of the Argonaut (previously known Prodigy Gold aka Kodia) Brenbar project. The second discovery zone at Asha is located south of the Quebec Sturgeon River Gold Mine area. Higher gold assay values were clustered along an E-NE trend over a 1.8km of strike length.
Tehya was then stripped of overburden to expose the mineralized zone for mapping and channel sampling, following two promising diamond drill hole results in the area.
Initial sampling by GeoVector of the waste stockpile at the Quebec Sturgeon River Gold Mine returned a range of 0.06 g/t gold to 10.2 g/t gold with an average grade of 2.83 g/t gold from 8 random samples. It was reported in 1984 that a bulk sample extracted at that time by front end loader returned an average of 2.95 g/t gold. On the basis of these initial encouraging results, Laurion commissioned a comprehensive program to accurately determine the location and volume of the waste stockpile, and to sample the stockpile using an excavator to dig pits to acquire representative samples throughout the stockpile. The survey of the stockpile and the tailings area was carried out by TBT Engineering Consulting Group of Thunder Bay.
LAURION also completed 5 deep diamond drill holes totalling 3,516m below the Quebec Sturgeon River Gold Mine workings to test the down dip extension of the #3 gold-quartz vein and also targeting the M, 10 and 11 quartz veins in the areas beyond 550m vertical depth.
LAURION acquired an undivided 100% interest in 13 mining claims totaling 179 units and primarily located in Pifher Township known as the Ishkoday North Claim Block.
LAURION retained Quantec Geoscience to complete two induced polarization surveys carried out on the NE Grid at the Ahki mineralization trend ('Ahki') and the SE Grid at Asha. The survey was carried out over 16 line kilometres with 100m line spacing and 25m station intervals using TDIP pole-dipole array for the IP and a GSM-19 Overhauser magnetometer.
Some 7 diamond drill holes totalling 1,104m tested anomalies on the NE Grid at Ahki, the Makwa minerlization trend ('Makwa') and at the Tehya Extension. All 7 holes intersected gold-silver-copper-zinc mineralization, indicating a different style of mineralization to the previously known lode gold quartz veins.
LAURION conducted a geophysical program on the Ishkoday East Claim Block consisting of total magnetic intensity (TMI) and horizontal loop electromagnetic (HLEM) surveying on the South Grid. The grid was laid out to test a weak helicopter-borne EM anomaly detected in a competitor’s VTEM survey over the area in 2010. Line-cutting was completed by Michael Goodman of Beardmore.
The S Grid was cut using 100m line intervals and picketed at 20m station intervals along the lines. A total of 2.2 line-km were cut and chained. Geophysical surveying was carried out under contract by Exsics Exploration Limited of Timmins (Ontario). TMI surveying was completed at 5m station intervals using field and base-station Scintrex ENVI proton precession magnetometers. In total, 2.2 line-km of TMI surveying was completed on the S Grid. An Apex Parametrics Max-Min II unit was used for HLEM surveying. In-phase and out-of-phase readings were manually recorded for 1777Hz and 444Hz frequencies using a 100m coil separation. Data were read at 20m station intervals. In total, 1.4 line-km of HLEM surveying was completed. GeoVector completed all geophysical data plotting and interpretation. Ground magnetic surveying effectively mapped an E-W trending magnetic anomaly that was shown by drilling to be due to massive and blebby porphyry. The HLEM survey did not detect the VTEM survey conductive anomaly.
A total of 6 diamond drill holes totalling 1,360m (LME11-018 to LME11-023) targeted multiple strong chargeability anomalies identified by the induced polarization survey on the SW Grid carried out by Quantec Geoscience on the Asha trend. Drilling totalling 280m (LME11-024 and LME11-025) examined the extent of the previously drilled Tehya at depth and along the 800m strike length between diamond drill holes LME10-07 and LME11-017.
LAURION commenced a prospecting program covering the Tehya, Ahki, the Loki and the A mineralization trends ('Loki' and 'A') precious metal rich sulphide trends.
The A NE Extension and Loki
Selected grab sampling took place in trenches located on the Beaurox Claim Block 250m NE and along strike of drilling completed by LAURION. A total of 14 samples were taken along 125m of strike length. Best assay results included 15.30 g/t gold, 77.8 g/t silver and 27.50% zinc.
The A SW Extension and Loki
The sampling took place in trenches located 440m SW and along strike of drilling completed by LAURION in 2011, which initially identified the Loki trend. Loki is now projected to be the SW strike extension of the A on the Beaurox Claim Block, and occurs approximately 400m S and parallel to the Tehya trend. A total of 7 selected grab samples were taken along 220m of strike length. Best assay results included 42.30 g/t gold and 18.80% zinc.
A2 Mineralization Trend (“A2”) and Loki
Selected grab sampling took place in trenches located 300m S and parallel to Tehya. A total of 7 samples were taken along 820m of strike length. Best assay results included 53.00 g/t gold and 23.5 g/t silver and 18.90% zinc.
85-A2 Mineralized Trend (“85-A2”) and Loki
Selected grab sampling took place in trenches located 150m S and parallel to the Tehya trend. A total of 8 samples were taken along 350m of strike length. Best assay results included 2.53 g/t gold and 91.1 g/t silver, 1.66% copper and 15.00% zinc.
Azurite Showing and Loki
Additional prospecting and mapping was carried out on a second copper showing designated the Azurite showing. While mapping thisshowing, a further zone of zinc and copper was discovered approximately 20m N of the Azurite showing. Assay results from selected grab sample #1384287 yielded 186 ppb gold, 12.4 g/t silver, 0.13% copper and 13.90% zinc; whereas selected grab sample #1384288 returned values of 959 ppb gold, 67.7 g/t silver, 1.29% copper and 4.80% zinc.
A4 Mineralization Trend (“A4”) and Tehya
The selected grab sampling took place in trenches located 200m NE of the 85-A2 sampling. The A-4 is possibly the extension of the 85-A2. A total of 8 grab samples were taken along 260m of strike length. Best individual assay results included 1.96 g/t gold, 133.0 g/t silver, 0.56% copper, 2.95% lead and 9.37% zinc.
River West and Name Ziibi Mineralization Trends (“River West” and “Ziibi”)
The selected grab sampling took place in trenches on the Ishkoday North Claim Block. Two sub-parallel mineralized trends were identified approximately 60m to 75m apart across strike. The northern river West was sampled over 350m of strike and is gold bearing. The southern Ziibi is copper, silver and gold bearing. A total of 8 selected grab samples were taken along 260m of strike length. Best individual assay results included 6.86 g/t gold and 48.9 g/t silver, and 1.86% copper.
River East Mineralization Trend (“River East”) and Ziibi
The selected grab sampling took place in trenches located on the northern portion of the Beaurox Claim Block at River East. The mineralization appear to be an on-strike extension of the copper, silver and gold zone on River West South. Samples were taken over 860m of strike length. A total of grab 8 samples were taken along 260m of strike length. Assay results were generally low; the best individual assay results include 11.9 g/t silver and 0.9% copper.
GeoVector completed an NI 43-101 Mineral Resources Estimates for the stockpile and tailings area associated with the processing of ore feed from the Quebec Sturgeon River gold Mine. The estimates for the stockpile was 144,070 tonnes grading 1.59 g/t gold for 7,383 contained ounces of gold in the Indicated category. The resource estimate for the tailing was 137,501 tonnes grading 1.67 g/t gold for 2,944 contained ounces of gold in the Indicated category. Total Indicated mineral resources for both the stockpile and tailings totalled 281,571 tonnes grading 1.14 g/t gold for 10,327 contained ounces of gold. The estimates were prepared by Dr. A. Armitage, P. Geo., an independent consultant to LAURION. The NI 43-101 report was filed on SEDAR.
Channel sampling followed up on several new discovery zones identified in a prospecting program.
J Vein Mineralization Trend (“J”) and Tehya
The J is located within Tehya and is proximal to the Ahki. The J is located 200m from the Ahki A6 vein, which during previous prospecting and mapping in 2010 returned a selected grab sample assay of 6.76 g/t gold, 10.2% zinc, 0.70% copper and 8.5 g/t silver, and 100m SE of LME11-017, which returned assays of 0.10 g/t gold, 10.1 g/t silver, 0.11% copper and 2.85% zinc over 5.85m, including 0.05 g/t gold, 14.9 g/t silver, 0.21% copper and 9.79% zinc over 1.30m, hosted within a package of intermediate volcanic rocks. The J was channel sampled from E to W and sampled on a 5m line returning assay intervals of 0.14 g/t gold, 10.3 g/t silver, 0.10% copper and 0.78% zinc over 1m; 0.69 g/t gold, 16.9 g/t silver, 0.07% copper, 2.95% zinc and 0.43% lead over 2.0m on an adjacent 15m line; and 0.12 g/t gold, 11.4 g/t silver, 0.11% copper and 2.27% zinc over 4.0m on the next 27m line.
Southwest R, K and C Mineralized Trends (“CRK”) and Loki
The Loki Trend occurs approximately 400m S and parallel to Tehya Trend. An 3 additional mineralized trends were located to the S and on strike with the A2 Mineralized Trend (“A2”) which had been drilled in late 2012, returning results of 12.84m of 3.31 g/t gold, 18.1 g/t silver and 3.72% zinc, including 4.04m of 5.25 g/t gold, 40.1 g/t silver, 8.38% zinc and 1.24% lead.
Channel sampling of the R gave assay intervals of 2m grading 1.22 g/t gold, 1.5 g/t silver, 2.28% zinc and 0.02% copper on a 3m line; 8m of 1.08 g/t gold, 4.9 g/t silver, 1.11% zinc and 0.08% copper on a 7m line, including 5m of 1.68 g/t gold, 7.0 g/t silver, 1.27% zinc and 0.10% copper, and 5m of 1.59 g/t good, 2.2 g/t silver, 2.04% zinc and 0.04% copper. Channel sampling on the K yielded 3m of 0.72 g/t gold, 2.7 g/t silver, 1.94% zinc and 0.04% copper on a 3.5m line; 4m of 0.99 g/t gold, 2.5 g/t silver, 2.15% zinc and 0.06% Cu on the 8m line; and 3m of 0.29 g/t gold, 7.8 g/t silver, 6.88% zinc, 0.08% copper and 0.19% lead on the 14m line. Channel sampling on the C produced 3m of 3.14 g/t gold, 23.2 g/t silver, 2.62% zinc, 0.20% copper and 0.15% lead on the 1m line. Channel sampling on a new C1 quartz vein gave 1.3m of 1.07 g/t gold, 1.4 g/t silver and 0.08% zinc.
A new horizon is postulated to exist south of Loki. Diamond drill holes LME11-014, LME11-015 and LME11-016 tested three IP targets following samples were also collected along this horizon. It appears that these holes fell short of the main Makwa; however all the holes intersected extensive zones of disseminated and stringer style zinc mineralization (sphalerite) and associated lower grade gold and silver with occasional copper mineralization.
LAURION completed a drill program was composed of a total of 533m of diamond drilling completed in 4 holes ( LBX14-016, LBX14-017, LME14-030 and LME14-031). Two additional strategic diamond drill holes (LBX14-018 and LBX14-019) totalling 424m tested the higher grade polymetallic A-Zone of the Loki Trend.
In early 2018, LAURION designed a long term 3-stage exploration program over a 3 to 5 year period with the prime objective of rapidly defining a significant near-surface bulk metal polymetallic system in the order of 10 million gold equivalent ounces that could potentially be mined in one or more open pits (the “Potential”). It was believed at the time there was sufficient evidence from the historical and LAURION’s work for this potential to exist in a 3km by 1km are containing all of the known precious and base metals mineralization known to date (the “Target Area”).
Stage 1 consisted of an initial field validation exploration program with a first-pass interpretation to prove the existence of sufficient polymetallic mineralization that may offer the proposed Potential. Some 80% of Stage 1 was completed in 2018. The remainder formed part of the 2019-2020 Stage 2 exploration program that is to determine the actual Potential of the mineralized system via further outcrop stripping, continuous channel sampling, assaying, 2D and 3D geological modelling, and targeting to outline specific areas at Ishkoday. The 2021-2023 Stage 3 exploration program would ultimately consist of defining the size of the Ishkoday mineralized system in Mineral Resources of all categories.
In Stage 1 - Phase 1 work from May to July 2018, LAURION recompiled the available Ishkoday data, and followed-up with prospecting of poorly explored areas of the North Claims and the Target Area of the South Claims in an expedited fashion in order to move the project to the next exploration phase. The activities included regional prospecting, limited regional geological mapping and the prospecting of known mineralized “veins” and their extensions, and new areas in the less explored North Claims, located north of the Namewaminikan River.
Some new mineralized quartz vein occurrences were discovered on the North Claims. These vein sets were systematically manually stripped and sampled. Outcrop stripping, mapping and sampling was also done in the southern portion of the claims including the “85-A2” gold-quartz vein system and the polymetallic base metal veins. Hand stripping was completed in two areas, the “Jack showing” adjacent to Highway #801 and the 5157 area which was southwest of the 85-A2 Quartz Vein system.
The Phase 1 - Stage 2 work included mechanized and additional manual outcrop stripping, channel sampling and assaying. Two large stripped areas - Trenches or TR18-1 and TR18-2; were completed during this stage. Trenches were channel sampled in a semi-continuous fashion at 0.2m to 1.5m intervals. Trenches were designed to expose the favorable geology and veins associated with the 85-A2 Quartz Vein system (in TR18-1) and to test the lateral continuity of the gold mineralization and alteration on strike to the southwest.
Stripped area TR18-1 was constructed 1km NE of the Sturgeon River Mine. The stripping was designed to expose a suite of NE-SW gold bearing quartz veins carbonatized and/or sericitized selvages that include the 85-A2 and other gold bearing quartz veins previously identified and to channel sample them in a semi-continuous fashion. Veins pinch and swell along strike from a few centimeters to locally over a meter in width. Quartz veins contain minor pyrite and rare chalcopyrite. Free visible gold was common. The veins typically form anastomosing patterns. Thin 020° trending chlorite-magnetite polymetallic veins occur sparsely in TR18-1 and correspond to base metal values in the channel samples.
The stripped area TR 18-2 was designed to expose the geology and explore for gold bearing veins on strike with those veins exposed in TR18-1 (to the SW of TR8-1). The trench intersected volcaniclastic and tuffaceous volcanic rocks, felsic to intermediate flows and intermediate composition intrusive rocks similar to rocks in TR18-1.
The 2018 exploration program at Ishkoday focussed on determining the extent and grade of selective vein sets, whether gold-quartz or gold polymetallic veins and stockworks, which could further advance the overall potential. The work also enhanced the understanding of the mineralizing systems and confirmed the results of the historic work, and confirmed that the polymetallic base and precious metal systems are long lived, multi-generational events that are clearly associated with structures formed by the deformation events that have affected the area.
In 2018, LAURION completed total of 20 SONIC drill holes on the Stockpile for 185.3m, averaging 9.3m in a range of 3.7m to 15.2 m. Each of the SONIC drill holes was strategically positioned to sample the inner core of the Stockpile to a minimum of 1.5m below the base of the Stockpile. Assays and metallurgical results from this work are still pending. However, additional specific gravity work of the Stockpile indicates ranges of 2.20 to 2.40 t/m3, with a new volume range between 75,000m3 to 80,000m3 over an area of 12,000m2 or in the range of 150,000 to 190,000 tonnes, with gold grades between 0.67 to 1.59 g/t gold.
LAURION also completed Metallurgical laboratory test work on its surface stockpile. The purpose of the test work was a follow-up of the 2010 and 2014 testing, designed to evaluate the gravity recoverable gold followed by flotation of the gravity tailings to recover any remaining gold.
Some 60% of the gold was recovered to the Knelson concentrate at 187 times upgrading to 91.8 g/t gold. Gravity separation is most effective if the gold is liberated or locked with pyrite, and its performance may improve with finer crushing. A further 35% of the gold was recovered by flotation. Gold appears mainly as Electrum (98%), with the remainder in pyrite. Electrum is a naturally occurring alloy of gold, silver and trace amounts of copper and other metals, ranging from pale to bright yellow in color, depending on the proportions of gold and silver. The majority of both were recovered through gravity separation. 30% of the electrum is locked in silicates and is recoverable by flotation but will require further grinding to improve grade due to the fine-grained texture. The 2019 metallurgical study supports the previous 2010 and 2014 studies and adds to the gold potential of the Stockpile. All three metallurgical reports are available on the LAURION website.
Outcrop stripping totalling 41,067 m2 was completed in 6 areas, of which 22% was rehabilitated in 2019:
- TR18-3 at the M24 Quartz Vein for 5,294 m2 covering trenches numbered #1, 9, 10, 15, 16, 19, 21 and 24;
- TR19-1 at the Nos. 1, 2, 3 and 8/11 Quartz Veins (including the Coniagas Quartz Vein) for 4,943 m2 covering trenches numbered #2, 4, 5, 6, 8, 11, 22 and 23;
- TR19-2 at the CRK Zone Oxide-Sulphide, Sulphide and A-2 Quartz Veins for 14,173 m2 covering trenches numbered #31 to #37, #39, 40, 41, 54 to 58, and 62 to 64;
- TR19-3 at the Marge, “F” and “X” Quartz Veins for 11,694 m2 covering trenches numbered #42 to 53 and 60;
- TR19-4 at the M23 and M25 Quartz Veins for 2,425 m2 covering trench numbered #61;
- TR19-5 at the A9 and Nos 8/11 Quartz Veins for 2,538 m2 covering trench numbered #59;
Additional channel samples were taken from TR18-1 East covering the NE extension of the 85-A2 Quartz Vein;
Channel samples taken in 2018 from stripped outcrops TR18-1 and TR18-2 were re-measured for their length and azimuth, and outcrops were re-mapped;
A total of 3,581 channel and 239 selected grab samples were sent to ALS Group laboratory for assay and limited litho-geochemical analysis:
- Samples were analyzed for either their gold or gold, silver, copper, lead and zinc content;
- 96 samples were tested for whole rock and trace element geochemistry;
- 87 samples were tested by the Metallic Screen method;
Pioneer Aerial Surveys completed in August 2019, an airborne drone magnetic survey with low altitude photos;
A drill core re-logging exercise was also completed as part of standardize rock units, their contacts, structures, outlining veins and structures, all to define litho-structural domains – the exercise will help complete the first comprehensive geological map incorporating all current and historical work on Ishkoday;
LAURION embarked on the database review in August 2019 ensuring that all of the historic and current geological and exploration information from Ishkoday was processed and compiled which compilation, synthesis and interpretation. The detailed work done included:
Upgrading the leading-edge Ishkoday Master Database for eventual geological modelling and mineral resources estimations of the “A” Zone. The information included creating files for the:
- GIS Compilation with 3D layer files; infrastructure; channel samples and drill holes having UTM coordinates and elevations; assays and litho-geochemistry, metal and litho-geochem plots and isopach contour maps; geology; geophysics; Google EARTH; grids; hydrology; mineralization; historic mining; sections; topography; and the upgrading the MASTER DATABASE file; and
- 3D Model with topography; structures; gold-quartz veins, oxide-sulphide and sulphide veins, geology (diorite, diorite breccia, mafic dykes); and mineralization trends and domains, all to create the Ishkoday Geology and Target Model Map.
A total of 7,937m of NQ size drill holes (31 drill holes) was completed on the A-Zone, McLeod, Joe, Ahki/Azurite and CRK Zones, located in the north east Ishkoday Project. Phase two 2020 drilling ended on a high note, with a high-grade discovery interval within the total intercept which assayed 48.69 g/t Au, 35.98 g/t Ag, 1.14 % Cu over 5.40 m, including 441 g/t Au, 191 g/t Ag over 0.57 m discovered in drill hole LME20-031 in the New Niish Zone.
The 2020 drilling provided a new geological understanding, confirming the presence of volcanogenic mineralization (A-Zone type) over the whole strike length between the McLeod Zone and A-Zone. The strike length across the mineralized zones is approximately 1.4 km, with a confirmed depth up to 150 m from the surface.