Archive for category Ground

Unlocking Australia’s hidden mineral potential with geophysics

Posted by on Friday, 1 August, 2014
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Dr Richard Blewett:

“It is becoming increasingly difficult to discover near-surface mineral resources in Australia. New and innovative products and techniques are being developed as part of the UNCOVER Initiative to help attract mineral exploration investment that has the potential to lead to the discovery of new resources.”

One of the focus regions for the UNCOVER Initiative is the Thomson Orogen: “The Thomson Orogen is a large area that lies to the north and west of the Lachlan Orogen in New South Wales, South Australia, the Northern Territory and Queensland. Much of it is under the cover of younger sedimentary basins, with some up to several kilometres thick, and it is therefore a poorly understood element of Australia’s geology.

The southern Thomson Orogen is true ‘greenfields’ country. Although the mineral potential of the region is largely unknown, the northeastern Thomson Orogen (for example Thalanga, Charters Towers) and the similar-aged Lachlan Orogen to the south are well mineralised (for example Cadia, Northparkes, Lake Cowall Cobar). In order to attract exploration investment into the southern Thomson Orogen, and also to improve the geological understanding of the area, Geoscience Australia, the Geological Survey of Queensland and the Geological Survey of New South Wales have commenced a collaborative project to collect new (and synthesise existing) pre-competitive data.

One of the first steps in this collaboration is to acquire airborne and ground geophysical data including airborne electromagnetics (AEM), gravity and magnetotelluric (MT) data. Regional AEM data has now been collected to map cover thickness and assess the geology and prospectivity of the Southern Thomson Orogen across the New South Wales-Queensland border around Hungerford and Eulo. These data will be interpreted using existing borehole stratigraphic data and a new solid geology compilation of the region developed between Geoscience Australia, the Geological Survey of Queensland and the Geological Survey of New South Wales.

 

The Geotech VTEM FullWaveForm
airborne electromagnetic acquisition
system used in the Southern Thomson
Orogen airborne electromagnetics survey.
Image credit: Geotech Airborne Limited.

 

 

 Geoscience Australia is a leading promoter of AEM surveying for regional mapping of cover thickness, under-cover basement geology and sedimentary basin architecture. Geoscience Australia flew three regional AEM surveys during the 2006-11 Onshore Energy Security Program (OESP): Paterson (Western Australia, 2007-08); Pine Creek-Kombolgie (Northern Territory, 2009); and Frome (South Australia, 2010) [1]. The surveys were primarily designed to provide reliable, fit-for-purpose pre-competitive AEM data for mapping critical features of uranium mineral systems.

Results from these surveys have now produced a new understanding of the architecture of critical mineral system elements and mineral prospectivity for a wide range of commodities of these regions and includes details on the thickness and character of the regolith, sedimentary basins and buried basement terrains. The data have since been found suitable not just for uranium, but for mapping a range of other mineral systems including gold, silver, copper, lead, zinc and potash, as well as for under-cover geological mapping and groundwater resource estimation.

The survey data are now processed using the National Computational Infrastructure (NCI) facility at the Australian National University to produce GIS-ready interpretation products and GOCADTM objects suitable for 3D modelling.

A number of 3D models are being developed to interpret the near-surface under-cover geology of cratons and mobile zones, the unconformity surfaces between these and the overlying sedimentary basins, and the architecture of those basins. These models are constructed primarily from AEM data using stratigraphic borehole control and show how AEM data can be used to map the cross-over area between surface geological mapping, stratigraphic drilling and seismic reflection mapping. These models can be used by minerals explorers to more confidently explore in areas of shallow to moderate sedimentary basin cover by providing more accurate cover thickness and depth to target information. A 3D model of basement-cover relationships and depth of cover will be developed for the southern Thomson Orogen.”


Ground EM and gravity for a Ni-Cu-PGE project in Greenland

Posted by on Friday, 25 July, 2014

North American Nickel Inc. announces the completion of surface geophysical surveys and identification of electromagnetic and gravity anomalies at the Company’s 100% owned Maniitsoq nickel-copper-cobalt-PGM project in southwest Greenland.

Surface time domain electromagnetic (TDEM) and gravity surveys were initiated at the Maniitsoq project in mid-April and were completed in mid-June. The surveys were carried out by Crone Geophysics of Mississauga, Ontario and focused on two areas, the Imiak Hill Conduit Complex (IHCC) and Fossilik, where previous drilling intersected significant Ni-Cu-PGE mineralization (See Figure).

Preliminary TDEM results indicate the presence of EM anomalies correlating with both existing mineralization and also representing new geophysical targets. Preliminary gravity results indicate that gravity anomalies exist in both the Imiak and Fossilik areas and correlate with noritic intrusions identified from both surface mapping and drilling. Several of the known nickel-copper occurrences are empirically observed to occur at the margins of these gravity highs.

NAN President and Interim CEO, Mark Fedikow, commented: “The 2014 exploration program is well underway and completion of the surface geophysical surveys over the IHCC and Fossilik areas is an important component in our exploration strategy. The addition of gravity surveying this year represents a valuable new tool for exploring the Company’s large Maniitsoq property where noritic intrusions occur over a 75 km strike length. Identification and correlation of gravity highs with two of the known mineralized norite intrusions in the belt indicate that gravity will be very useful in mapping the subsurface extents of mafic and ultramafic intrusions and in helping to understand the distribution of related nickel-copper sulphide mineralization”.

TDEM surveying totaling 87 line km have been completed in the IHCC and Fossilik areas located in the central portion of the Maniitsoq property. Data interpretation and modeling are in progress and results are being used to target both follow-up drilling as well as define new targets for potential drill testing.

Gravity surveys were completed over the IHCC and, based on favorable results, an additional gravity survey was carried out over the Fossilik area. In each area, the surveys consisted of a core of gravity readings at 50m stations on 200m line intervals surrounded by more widely spaced readings typically on 500m centers. Gravity readings were taken at a total of 944 stations. The preceding comments are based on initial data modeling and inversions.

At the IHCC (see Figure 2), several gravity highs are observed to be coincident with, or flanking, the mapped and interpreted norite outcrops. Gravity inversion modeling shows one of the gravity highs to be coincident with the mineralized Spotty Hill norite intrusion. This gravity high extends south of the current Spotty drilling and also extends to the northwestward towards the Imiak North area. Another larger more complex double lobed gravity high lies in the immediate vicinity of the mineralized Imiak Hill norite intrusion. One lobe of this gravity high extends south of the Imiak Hill drilling and the other lobe lies to the NW.

GravityNAN

At the Fossilik area located 9 km southwest of the IHCC (see Figure 3); gravity surveying identified a large ~1.5 km x 2.5 km gravity high which is coincident with the Fossilik norite intrusion. Surface nickel occurrences and nickel mineralization intersected in historic drilling and past drilling by the Company are observed to lie at or near the southwestern and western margins of this gravity high.

Data interpretation and modeling are on-going but results to date indicate that gravity data will be a useful tool to aid in mapping the sub-surface extents of the target noritic intrusions, particularly as compared to the magnetic data where correlation of anomalies with norite intrusions is less consistent. Additional images of the gravity inversions may be viewed on the Company’s website.

- See more at: http://www.northamericannickel.com/news/news-details/2014/Surface-Electromagnetic-and-Gravity-Geophysical-Surveys-Completed-and-New-Anomalies-Identified-at-Maniitsoq-Nickel-Sulphide-Project-in-Greenland/default.aspx#sthash.fnhpBAK6.dpuf

To view the photo associated with this press release, please visit the following link: http://media3.marketwire.com/docs/958596a.pdf.


A set of geophysics for Iron Oxide Copper Gold deposit in Quebec

Posted by on Thursday, 17 July, 2014

Honey Badger Exploration Inc.  has completed the interpretation of the geophysical data over the Delhi Pacific copper showing on its Sagar Property. The coincident gravity, magnetic, electromagnetic (“EM”) and induced polarization (“IP”) anomaly associated with the Delhi showing are typical of those expected from an Iron Oxide Copper Gold (“IOCG”) deposit.

The IOCG model is further supported by the presence of a favourable structural setting for an IOCG deposit, namely the abundance of polymetallic showings (copper-gold-silver-cobalt) and the presence of diagnostically verified IOCG hydrothermal alteration.

At the Delhi Pacific showing, historical significant drilling intersections include 45.81 metres @ 0.51% copper and 10.7 metres @ 0.78% copper. While these intersections were not tested for silver, gold or cobalt, historic and recent grab samples* contain up to 1.8 grams per ton (“g/t”) gold, and up to 35 g/t silver.

*Grab samples are selective by nature and are unlikely to represent average grades of the deposit(s).

The selection of new drill targets is based on an interpretation of the IP/Resistivity, airborne magnetics, ground gravity and airborne EM data. In the winter of 2014 ClearView Geophysics Inc. completed a Surface Spectral IP survey over part of and extending east of the Delhi Pacific showing (Figure 1).

To view ‘Figure 1 – Surface Spectral Induced Polarization survey location lines’, please visit the following link:http://media3.marketwire.com/docs/honef10715.pdf

The interpretation indicates an anomaly associated with the historic drilling at Delhi that increases both in intensity and size east of these drill holes for more than 1.5 kilometres. The apparent resistivity data is presented in Figure 2 (red-purple indicates low resistivity and represents the target area):

Figure 2 – Resistivity Data at Delhi Pacific

The gravity data indicates that the southwest side of the magnetic high zone at Delhi Pacific coincides with a gravity low feature, whereas to the north is a gravity high. This indicates that the resistivity low/chargeability/electromagnetic target is located along a major structure that represents a favourable event for IOCG mineralization. The target area at Delhi covers more than 3 square kilometres: approximately 1.5 kilometres in strike length multiplied by an average width of 200 metres (Figure 3).

‘Figure 4 – Magnetic Inversion over Delhi Pacific’


IP and magnetic surveys in Ontario for gold

Posted by on Thursday, 26 June, 2014

HARTE GOLD CORP. (“Harte Gold”)CA:HRT -8.70% (frankfurt:H4O) is pleased to announce the completion of the expanded Phase Two Induced Polarization (“IP”) survey on the Sugar Zone Property, located 60 kilometers east of the Hemlo gold mines currently being operated by Barrick Gold Corporation.

Phase Two IP Survey

The survey was successful in identifying significant extensions to the five high priority IP anomalies located “up- ice” of the Peacock boulder train identified in the Phase One survey (see news release dated June 2, 2014). In addition, significant extensions to both the Wolf Zone and the Sugar Zone Deposit were discovered, as well as several new IP anomalies en echelon to each of the Wolf Zone and Sugar Zone Deposit. See attached map.

The five high priority IP anomalies were traced an additional 700 meters to the north. These IP anomalies are now 1,200 meters long while other parallel anomalies are 1,000 meters to 1,600 meters in length.

Magnetometer Survey

A detailed ground Magnetometer (“Mag”) survey has been completed over the entire grid covered by the two IP surveys. The Mag survey took readings every two meters and will assist in classifying the IP anomalies and help to define structures that are controlling mineralization and/or off-setting zones, as well as locate any younger mafic dikes (diabase dikes) that cut across the stratigraphy.

In the course of cutting and traversing the grid, many newly discovered rusty boulders have been located as well as other angular sericitic slabs. A program of detailed mapping, boulder tracing and sampling, and a limited till sampling program will be carried out over the next three weeks prior to drilling in order to properly prioritize drill targets. This occurrence of mineralized boulders suggests there may be a number of bedrock sources for any new mineralization. Every IP anomaly found in the survey area will be tested in order to confirm mineral content.


Induced Polarization Survey in Newfoundland

Posted by on Wednesday, 25 June, 2014

Canstar Resources Inc.  announces the commencement of its summer exploration program, beginning with a ground geophysical survey at its Mary March Property near Buchans Junction, Newfoundland. Canstar will be implementing a deep-penetrating induced polarization (or “IP”) geophysical survey in order to enable maximum depth visualization on the property, with focus on the wide mineralization encountered near the Nancy April Zone. This type of technology and depth penetration represents the most detailed and comprehensive survey of its kind to have ever been conducted on the property and utilizes state-of-the-art geophysical methods. The results of this survey will be used for target generation where any new targets will be drilled in the subsequent drilling program also anticipated in the coming months.

2014 Induced Polarization Survey

In contrast to previous geophysical methods utilized on the Mary March Property throughout its exploration history, the IP method is not hindered by potential poor conductivities. It is now well established that the prevalent mineralization at Mary March is very similar to that of the former producing Buchans Mine, which is that of a zinc-rich mineralization with poor electro-conductive properties; the Buchans Mine was one of Canada’s all-time highest grade VMS ore producing 16.2 million tonnes averaging 14.50% Zn, 7.56% Pb, 1.33% Cu, 126 grams per tonne (g/t) Ag and 1.37 g/t Au between 1928 and 1984. By utilizing an IP geophysical method, Canstar hopes to detect these otherwise difficult-to-find mineralized areas where we understand there to be the highest potential for mineralization based on geology and previous drilling. The technology for IP geophysical methods has advanced in the last decade such that detection capabilities are now common to vertical depths in excess of 300 meters. Such advancements will greatly enhance Canstar’s capability in unraveling both the mineralization on the Mary March Property and the structure that controls it.

Details about the project (pdf)


An exploration program on the Samaqua property (Quebec) with airborne and ground geophysics

Posted by on Thursday, 19 June, 2014

The property is located north of Girardville in the Saguenay-Lac-Saint-Jean region of Québec, Canada, close to the Crevier project.

Work will consist of a helicopter-borne geophysical survey and an induced polarization ground survey on a circular anomaly. MDN plans to carry out about 1,500 metres of drilling on the target once the geophysical surveys are complete. The goal of the exploration program is to confirm the presence of a carbonatite or an alkaline system with the potential to host niobium/tantalum mineralization.

The Samaqua property covers a magnetic geophysical response similar to the one associated with Niobec Inc.’s niobium mine. The magnetic signature lies 23 km southeast of the Crevier deposit and 130 km northwest of the Niobec mine. The magnetic response is circular in shape with a strong magnetic aureole surrounding a weak magnetic core, which is identical to the magnetic response of the Niobec mine. In the case of Niobec, the core corresponds to a niobium carbonatite with a rare-earth-rich centre.

The circular anomaly lies at the southeastern edge of a lineament visible on the regional geophysical survey maps of Quebec’s Ministère de l’énergie et des ressources naturelles (see map). The northwest end of the lineament coincides with the porphyry syenite dike that hosts the Crevier niobium /tantalum deposit, and the southeastern extension of the lineament could be the southeastern extension of the dike, which would connect the two systems.

The results of interpretation suggest that the magnetic signature to the southeast of the Crevier deposit could correspond to other carbonatite-type mineralization with a niobium or rare-earth centre. Furthermore, these would be related to the Crevier deposit by the lineament that could be the southeastern extension of the Crevier dike. The Samaqua intrusive is part of the Saguenay-Waswanipi structural corridor that includes the Saint-Honoré carbonatites (Niobec) and Crevier alkaline complex in the Grenville region and the Lac Shortt and Montviel carbonatite in the Abitibi region.

Map: Magnetic geophysical response of the Sasguenay-Waswanipi structural corridor 

Samaqua

Geology and mineralization

The property occurs in the Grenville geological province.  According to the regional geological map published by the Quebec government, the northern part of the property is underlain by migmatite and granitic rocks, including pegmatite, whereas the southern part is composed largely of coarse-grained porphyritic mangerite, an intrusive rock of intermediate composition typically found in metamorphic terranes of Proterozoic age like the Grenville.

The property occurs just to the SE of the Crevier Nb-Ta deposit, along the projected extension of the nepheline syenite dyke that hosts approximately 25.39 million tonnes (Measured + Indicated) at 1960 ppm Nb2O5 and 2349 ppm Ta2O5.  Historical prospecting work located pegmatitic syenite outcrops on the property, which are highly indicative of the presence of an alkaline intrusive favourable to metals like those at Crevier (niobium-tantalum) and /or Niobec (niobium and rare earths).


Six Graphite-Rich Zones at Buckingham Graphite Property, Quebec after airborne and ground geophysics

Posted by on Monday, 9 June, 2014

CAVAN VENTURES INC.  announces it has exposed graphite-rich zones as a result of trenching on its 100%-owned Buckingham graphite property, located adjacent to the historic Walker Graphite Mine in Buckingham Township, Quebec. Graphite-rich zones were exposed in six trenches, and channel samples were collected from two trenches over a combined distance of 59.5 meters. Graphite-rich outcrops at the same location as one of the trenches assayed at 21.7% C.

Peter Swistak, President of Cavan states, “We are extremely pleased that many of our airborne EM anomalies identified last year are now confirmed as graphite mineralization. Our ground geophysics was able to confirm the anomalies in real-time, which allowed us to quickly expose the mineralization and collect samples for assay. We anticipate highly positive results and intend to return for further exploration in the coming weeks.”

In May the Company engaged Magnor Exploration Inc. (La Baie, QC) to conduct a short exploration work program. Ground-based geophysics was used to ground-truth airborne EM anomalies identified last year using the PhiSpy portable TDEM system. PhiSpy generates real-time EM profiles of the area being surveyed, and can detect buried conductors to approximately 10m depth. Dube & Desaulniers Geoscience (Ottawa, ON) was engaged to collect 3.3 line-km of survey data over priority airborne EM anomalies using the PhiSpy system. The real-time interpretation of TDEM data allowed the Company to execute trenching on several high priority targets.

A total of six trenches ranging from four to 48 meters in length and two meters in width were completed. Trench 22C was cut for 24 meters in a northwest direction, with a second perpendicular trench cut at its southeast end for 20.5 meters. Graphite-rich zones were exposed in both directions, and channel samples were collected over most of both trench lengths for a total of 33.9 meters. Mineralization at Trench 22C is still open to the north, with some visible flakes in the trench up to one centimeter in diameter. A rock grab sample assayed previously from this location returned 21.7% C (see news release, July 8, 2013). Trench #1 was cut in a west-northwest direction, with visible graphite channel-sampled over 25.6 meters. Because of the rich nature of the mineralization, these samples and those from Trench 22C were immediately shipped for assay.

A new graphite zone was also discovered roughly 150 meters east of Trench 22C, where graphite-rich veinlets in granitic-pegmatitic rocks contain graphite flakes over 5 mm in diameter. Additionally, an airborne anomaly approximately 400 meters north of the main set of conductors was confirmed by PhiSpy, but the program ended before this new target could be tested through trenching.


IP geophysical survey in the Lake Victoria goldfield of Tanzania

Posted by on Monday, 9 June, 2014

Tembo Gold Corp. (TSX VENTURE:TEM) (FRANKFURT: T23) (“Tembo” or the “Company”) is pleased to report progress on its 2014 work program on the Buly Trend target area on the Tembo Property in the Lake Victoria goldfield of Tanzania. A first drill hole has tested the Buly trend in the vicinity of artisanal workings and an IP geophysical survey has been completed and an initial diamond drill hole through a resulting significant anomaly has commenced. This anomaly is located along the interpreted projected extension of the structure that hosts the Reef 1 orebody at Bulyanhulu Mine.

IP Geophysical Survey
Spectral Geophysics has recently completed an IP survey measuring chargeability and resistivity. The survey was designed to probe to depths in excess of 800m, over a grid adjacent to the Bulyanhulu-Tembo boundary. Initial 200m spaced northeast oriented lines identified areas of interest over which the line spacing was closed to 100m to improve the 3-D model resolution.

The IP survey has revealed a weak sub-vertical chargeability anomaly, developed to a depth exceeding 650m along the Reef 1 trend commencing some 1500m from the boundary with the Bulyanhulu mining licence. This anomaly weakens slightly towards the northwest but approximately 400m further in this direction it strengthens significantly, particularly at depth and for 700m to the northwest to the end of the surveyed grid. The geophysical interpretation indicates that the chargeability response is increasing towards the end of the grid and becoming shallower and is open in that direction. The 3-D modeling of the geophysical response has provided the necessary information to plan initial test drill holes.

A second chargeability anomaly is located approximately 500m to the north, extending in depth from -50m to -450m where it becomes weaker. This anomaly extends some 600m along a northwest trend, parallel to the anomaly that is now being drilled.

Highlights of the Buly Trend work program include:

  • A strong magnetic lineament characterizes the interpreted extension of the structure hosting Reef 1 at Bulyanhulu Mine;
  • A 200m artisanal working is located along this trend;
  • TDD0001, drilled through this lineament beneath the workings, intersected a strong broad brittle-ductile shear zone with associated quartz veining but little sulphide and minor Au;
  • Initial IP has revealed a strong chargeable and resistive zone along strike at depth to the northwest along the trend at the Ngula 2 target, which has a highly active artisanal working located immediately to the northeast at surface;
  • The Ngula 2 target has consistently returned high grades from grab samples of the artisanal production: and
  • Drilling of the first drillhole to test the IP chargeability anomaly has commenced.

David Scott President & CEO stated, “The Buly Trend has for very obvious reasons always been considered an important target for the Company. The initial drillhole confirmed that at least one and probably more major shear zones are present in this area and appear to relate directly to the northwest extension of the Bulyanhulu system. The just-completed IP survey now provides us with strong evidence of potential sulphide mineralization possibly associated with a strong shear structure along this same Buly trend. The outcome of the first drillhole testing the chargeability zone is eagerly anticipated. “

Geology of the Buly Trend
The geology of the Bulyanhulu Mine sequence trends northwest into the Tembo licence area. Two northwest-trending structures that host the resource at Bulyanhulu (Reef 1 and Reef 2 450-500m apart), are believed to continue in a northwesterly direction through the boundary separating the properties. Reef 1 is located in a brittle-ductile shear structure located largely within an argillaceous meta-sediment on a mafic-felsic metavolcanic contact. A number of other sub-parallel magnetic lineaments are evident across a broad northwest-striking metavolcanic sequence. These structures commonly occupy contacts between individual lithological units consisting of stacked metavolcanic flows, alternating mafic and felsic meta-volcanic rocks and associated meta-sediments.


The borehole IP survey near Val d’Or, Quebec

Posted by on Friday, 9 May, 2014

Alexandria Minerals Corporation  reports on preliminary results from the recently completed, down-hole Induced Polarization (“IP”) Survey on its Akasaba property. Survey results yielded several strong targets on both the main Akasaba Mine Trend and the nearby parallel North Zone, adding to high priority drill targets in preparation for this summer’s drill program.

The principal geophysical targets on the main Akasaba and North Zones are up to 400m long along strike, open to the east, and open at depth. The anomalies, located below and to the east of the Akasaba Current Resources, are similar to those intersected by previously completed gold-bearing drill holes that contain 11.35 g/t Au over 6.0 m, 6.19 g/t Au over 5.05 m, and 4.69 g/t over 5.00 m (see Figures 1 and 2 below).

To view Figure 1, please visit the following link: http://media3.marketwire.com/docs/Figure1_AZX.pdf.

Eric Owens, President and CEO, stated “These are very encouraging results, and we are looking forward to testing these targets with drill holes. Through geophysical surveys and this past winter’s drilling, we have generated several strong targets for this summer’s 10,000 m drill campaign in an effort to build on our existing gold resources. We are still awaiting further geophysical results and drill assay results, which should provide further targets for testing.”

To view Figure 2, please visit the following link: http://media3.marketwire.com/docs/Figure2_AZX.pdf.

The borehole geophysical (Hole-to-Hole Resistivity/IP) survey was conducted during the winter by Abitibi Geophysics. The survey was designed to investigate potential targets at depth around the Akasaba Current Resources. The survey used a conventional induced polarization technique, with a borehole-to-borehole array based on 19 pairs of holes. Once all the data combinations are collected, a 3D inversion uses all the readings simultaneously in order to estimate the location and volume of the anomalies. Validation of the geophysical results are provided by past Alexandria drill hole assays, which show excellent correlation between well mineralized gold-bearing zones and strong Induced Polarization anomalies.

Elsewhere, the Company is awaiting assay results from the recently completed 4,000 m drill program on its Sleepy project, located 12 km east of the Akasaba project.

GEOLOGY

The Akasaba property straddles the Cadillac Tectonic Zone (CTZ) and is underlain by the Val d’Or Formation, Heva Formation, Cadillac, Piche and Pontiac Groups. The main Mine Horizon lies approximately 600 m north of the CTZ and consists of basalt-andesite-rhyolite volcaniclastic rocks, tuffs and flows intruded by gabbro and diorite sills, and is bound on the south by massive dacite.

Akasaba hosts polymetallic mineralization, with widespread silver (up to 50 g/t) and copper (generally 0.2-0.4%, locally up to 1-2%), and local high grade zinc (up to 6.35% Zn over 0.3 m in a massive sphalerite-pyrrhotite layer), and local molybdenum. The following characteristics are pertinent to the any operating model:

  • Gold and gold-copper resources are hosted in a shear zone (the “Mine Horizon”)
  • There are numerous similar sub-parallel gold mineralized zones in addition to the Mine Horizon
  • The Callahan tonalite intrusion, which is located a short distance northwest of the deposit has a prominent metamorphic/metasomatic halo, characterized by widespread and locally intense calcium and iron metasomatism (“Skarn”), in the form of epidote, chlorite, magnetite, amphibole, garnet
  • The Mine Horizon, with gold , copper and molybdenum, and other base metals, occurs within the metasomatic halo
  • Within the Mine Horizon, there is an east west zonation relative to the Callahan Intrusive: proximal Au-Cu-Mo, medial Gold (+/- Ag, Cu), distal Ag, Zn
  • Host volcanic rocks contain up to 30% or more pyrrhotite (+/- Chalcopryite, Sphalerite) as lenses, pods and layers, and massive layers of intergrown pyrrhotite and sphalerite, suggesting a component of synvolcanic mineralization probably unrelated to gold.

Such characteristics are similar to those found in the La Ronde-Doyon-Bousquet district 45 km to the west, a gold-copper-zinc enriched mining district which has seen more than 26 million ounces of gold produced from a 7 km long trend, a trend that is 1/5 of the size of Alexandria’s property.


Airborne and ground geophysics for precious metal project in Mexico

Posted by on Monday, 5 May, 2014

Orex Minerals Inc. announces completion of an airborne geophysical survey at its Los Crestones precious metal project, Sinaloa, Mexico. The 4,168 hectare helicopter-borne radiometric and magnetic survey was flown at 50m line spacing by MPX Geoservices Ltd. Data are being processed and results are expected in the coming weeks. In addition, Orex has signed a contract with Quantec Geoscience Ltd (“Quantec”) to undertake an 18 line-kilometre TITAN 24 DCIP (Direct Current resistivity and Induced Polarization chargeability) ground geophysical survey.

The proposed survey comprises 5 lines, each 3.6km long and 400m apart and will be the first ground geophysical survey to be conducted at Los Crestones. During the work Quantec will also collect MT (Magnetotelluric resistivity) data on the central grid line. Scheduled to commence mid-May, the survey is centred over mineralized structures previously tested by shallow diamond drilling in 2011. Orex expects the results to augment existing geophysical, geochemical and geological datasets and intends to use the results to identify additional areas for drill testing later in 2014. Surveying and clearing of grid lines is currently underway.

According to Orex’s President, Gary Cope, “The known mineralized structures may be only a portion of the bigger picture at Los Crestones. Utilization of airborne and deep penetrating surface geophysics at this stage of exploration will allow our geological team to refine drill targets for testing in the latter half of 2014. “

The property was drilled previously by Astral Mining Corporation (“Astral”) now merged with Orex (news release February 12th, 2013). In late 2011 Astral completed 2,618m of HQ and NQ diameter core drilling in 18 holes. Drilling tested three mineralized structures which outcrop at surface. Significant intercepts were identified in many of the holes and may be viewed at www.orexminerals.com/s/Drilling-LosCrestones.asp. Reported results included a best intercept of 5m averaging 39.1 g/t Au, 93.3 g/t Ag and 2.13% Cu from 55m depth in HQ drillhole 11LD011. True width of this interval from the Bohemia structure is approximately 3.53m.

LOS CRESTONES GOLD-SILVER-COPPER PROJECT SINALOA, MEXICO

The Los Crestones project totals 4,168 hectares and is prospective for economic gold, silver and copper mineralization. Mineralization includes north-south oriented structural zones hosting quartz veins, quartz stockworks and breccia fill possibly related to a deeper porphyry and/or diatreme system. Three main structural zones were targeted in the first phases of work. Corona, Bohemia and Indio are elongate structures recognized on surface as erosion-resistant silicified ribs or “crestons”. The airborne and ground geophysical programs commissioned by Orex are designed to complement ongoing geological mapping and geochemical sampling. Orex intends to develop drill targets over the summer; diamond drilling is scheduled for late 2014.

Geology and Mineralization

The property is underlain primarily by volcanic and intrusive rocks. At lower elevations andesite and dacite are seen within an erosional window in creeks and drainages and are representative of the “Lower Volcanic Sequence” commonly recognized throughout western Mexico. At higher levels the sequence is capped by rhyolites of the “Upper Volcanic Sequence”. Felsic to intermediate intrusive rocks are also observed over a large proportion of the property. The INEGI 1:50,000 G13-C12 map sheet depicts two intrusive bodies on Los Crestones though Orex geologists have observed outcropping intrusive material across the property.

Mineralization is concentrated within a series of silicified, north-south trending quartz stockwork and breccia zones most prominent in the southern half of the property. Three structures subject to the most work to date are named “Corona”, “Bohemia” and “Indio”. Historically these structures have been tested in small pits and underground workings, many of which are still accessible today, the largest comprising some 40 m of development. Additional mineralized structures have also been identified and require follow up work.


Supervised Neural Network Targeting and Classification Analysis for Mineral Exploration

Posted by on Tuesday, 29 April, 2014

Karl Kwan (Geotech LTD) presented at Canadian Exploration Geophysical Society meeting (8 April 2014) methodology and examples of using Neural Network Targeting and Classification at mineral exploration.

“Geophysical survey contractors routinely offer multi-parameter data to clients. For example, a helicopter-borne survey may acquire Time-domain electromagnetic (TDEM), magnetic gradiometer and even gamma-ray spectrometer data (i.e., VTEMplus, Geotech LTD). Exploration geophysicists can certainly take advantage some of the readily available multi-disciplinary (geology, geophysics and remote sensing) and multi-parameter (potential field, EM, gamma-ray spectrometry, and others) datasets for mineral exploration. However, the integration and interpretation of these datasets can be time-consuming and even challenging, especially for large-scale datasets covering large areas with diverse geological conditions. The Supervised Neural Network (NN) Targeting and Classification technique for mineral exploration described and demonstrated by Reford, Lipton and Ugalde, 2004, “Predictive Ore Deposit Targeting Using Neural Network Analysis” (http://www.pgw.on.ca/downloads.html), can be a useful and promising tool for the analysis of multi-disciplinary and multi-parameter data.

In this presentation, the properties or responses of the two feed-forward multilayer Neural Networks, Levenberg-Marquardt (NN with LM training) and Fast Classification (FCNN), as implemented in the current version by PGW, are studied in detail. The supervised NN simulations are performed on specially constructed synthetic data. Intended as a tutorial and the NNs treated as black boxes, the objectives of the exercise are twofold, to demonstrate the targeting as well as classification capabilities of the Neural Networks, and at the same time to show one of the known limitations and to suggest a way to get around it. The utility of the NN tool is demonstrated again with real cases from the Republic of Niger.”

Geosoft is delighted to host the online portion of the Canadian Exploration Geophysical Society meeting with keynote speaker Karl Kwan, Geotech LTD.

YouTube:  


Airborne and ground geophysical surveys in Dominican Republic

Posted by on Tuesday, 29 April, 2014

GoldQuest Mining Corp.  announces that the Company has completed an airborne ZTEM geophysical survey covering its 100% owned Tireo Project, and has initiated its 2014 exploration program. Geotech Limited of Canada has flown 3,285 kilometers of flight lines, with investigation depths reaching 1.6 kilometers, allowing the Company to quickly and effectively evaluate the geological and mineral potential of the Tireo Project.

Results of the ZTEM Survey show:

  • A strong correlation between the Romero and Romero South mineralization
  • The Romero resistivity trend extends northwards over 1 kilometer past existing drilling and 0.5 kilometers south of Romero South
  • Additional new trends have been identified from the survey and field crews have been mobilized for ground follow up carrying out ground geophysics, along with geological and alteration mapping
  • An Induced Polarization (“IP”) program has been commenced over ZTEM targets

“The ZTEM survey has revealed a strong correlation between the new survey data and mineralization at Romero and Romero South,” commented Julio Espaillat, GoldQuest’s CEO, “The survey has provided us with key insights into the conductivity, magnetism, alteration and structure of the Tireo belt, with numerous targets showing similar properties to that of Romero. We are identifying exploration targets, and plan to announce the commencement of drilling shortly, to compliment the Romero Project’s Preliminary Economic Assessment (PEA) expected in the coming weeks.”

2014 Exploration Update:
Following the ZTEM survey, the Company is evaluating and ranking its regional exploration targets. The 2014 field exploration program has commenced and a focused ground IP program is underway. Insight Geophysics of Oakville, Ontario, Canada is on site completing the ground IP program. The IP program is designed to identify chargeable zones along the regional trends identified by the ZTEM survey and mapping. The starting point for the IP program was along trend and directly north of Romero. The Company anticipates that IP surveying will continue for several months. Two drill rigs are stationed at the Company’s field camp next to Romero. The Company will initially mobilize one drill rig and expects to commence drilling by the end of April.

At December 31, 2013, the Company had approximately $11 million in treasury and is funded to complete the 2014 work programs and beyond.

The data in this press release has been reviewed and approved by Mr. Jeremy Niemi, P.Geo., the Director, Technical Services of GoldQuest and a Qualified Person for the technical information in this press release under NI 43-101 standards.


Ground geophysics in Greenland for nickel-copper-cobalt-PGM project

Posted by on Tuesday, 29 April, 2014

North American Nickel Inc. announces that Crone Geophysics of Mississauga, Ontario have mobilized their crews to the Imiak Hill Conduit Complex (IHCC), part of the Company’s 100% owned Maniitsoq nickel-copper-cobalt-PGM project in southwest Greenland.

Geophysical Surveys Underway

The geophysical survey work now underway consists of surface time-domain PEM and gravity surveys in the Imiak Hill Conduit Complex, where significant nickel-copper-cobalt PGE mineralization has been intersected in drill holes by the company over the past two drill seasons. These intersections include:

  • Imiak Hill DDH MQ-13-028: 24.75 metres of near massive to massive sulphide grading 3.19% Ni, 1.14% Cu, 0.11% Co, including; 17.91m of 3.80% nickel, 1.42% copper, 0.13% cobalt and 0.01 g/t PGM;
  • Imiak North DDH MQ-13-029: 55.75m of disseminated to near massive and massive sulphide grading: 1.28% nickel, 0.36% copper, 0.04% cobalt, and 0.03 g/t PGM, including;9.99m of 4.65% nickel, 0.33% copper, 0.13% cobalt and 0.08 g/t PGM; and
  • Spotty Hill DDH MQ-12-005: 123.94 meters of disseminated, net-texture, to near massive and massive sulphide grading 0.81% nickel, 0.21% copper, 0.03% cobalt & 0.26 g/t platinum (Pt) + palladium (Pd) + gold (Au), including: 24.20 m @ 1.75% Ni, 0.34% Cu, 0.06% Co & 0.52 g/t Pt+Pd+Au.

Geological Team Meeting April 8-10, 2014 in Winnipeg

As preparation for the 2014 field and drill program all norite-hosted nickel sulphide mineralized drill targets were reviewed by the NAN Geological team and four invited geoscientists familiar with nickel sulphide deposits and advanced methods of interpretation of geophysical responses to nickel sulphide mineralization. The review was undertaken at a meeting convened in Winnipeg by North American Nickel with a view to expanding discovery possibilities and then confirming and prioritizing drill targets for this year’s drill program.

President Dr. Mark Fedikow P.Geo. states: “Our deepest hole to date at Imiak Hill in the IHCC intersected high-grade massive sulphide nickel-copper mineralization 185 m below surface. The new geophysical ground surveys are designed to look below that depth and define the extent and shape of our high-grade mineralized zones providing plunge, strike and dip attitudes for the mineralization. The results from these 2014 ground geophysical surveys coupled with the airborne surveys and drill results from 2012 and 2013 will assist with drill targeting at the IHCC. Our team worked last week with four seasoned and internationally experienced nickel sulphide geoscientists. The agenda included a thorough review of the IHCC and all the regional norite-hosted nickel sulphide targets identified as a priority for the 2014 season. We look forward to including them again along the path to discovery at Maniitsoq.”

The PEM Survey

The PEM system operates by placing a large loop of insulated wire on the ground through which a precisely-controlled changing current induces magnetic responses from conductors hundreds of metres deep in the ground. It can be used to detect and discriminate between a wide range of conductivities from poor (zinc), to excellent (copper and nickel). Due to its unique transmitted current waveform and its receiver’s measuring system, Crone has developed a step-response transformation of the data which extends this range of detection and discrimination into the extremely high conductance that is seen in nickel exploration. This feature has made the Crone PEM system an important part of the exploration efforts in nickel exploration camps around the world, such as the Raglan camp, Voisey’s Bay, Sudbury, Alaska, Tanzania, Western Australia, and now Greenland.

The Gravity Survey

In addition to the Pulse EM survey, Crone will carry out a gravity survey with a 2 person crew consisting of a gravity operator and a GPS operator with extensive experience in precision gravity surveys. The equipment consists of LaCoste & Romberg model G gravity meters with a reading resolution of 0.01 mGal. The differential GPS (DGPS) system is the Leica – model 1230 Dual Frequency, Dual Constellation (GPS & GLONASS) RTK, rover and Base Station with an accuracy of 1 cm + 1 ppm in separation from the base station to the rover. The crew has extensive worldwide experience and is capable of reducing the data to bouguer mGal values nightly in the field. Gravity surveys measure extremely small variations in the Earth’s gravitational field, which can be used to locate high density material such as nickel sulphide-bearing rock.


World class geophysics for Republic of Kazakhstan

Posted by on Sunday, 6 April, 2014

April 3, 2014, Astana. Vice Minister of Industry and New Technologies of the Republic of Kazakhstan Nurlan Sauranbayev and Chairman of the Board of JSC “Kazgeologiya” Galim Nurzhanov met with the Ambassador of Canada Stephan Millar and leading world class Canadian geophysical companies Phoenix Geophysics and Geotech Ltd.

“I want to thank you for the meeting. I see great potential for fruitful cooperation in the field of exploration, “- said Stephen Millar. Vice Minister of Industry and New Technologies Nurlan Suranbaev suggested for further cooperation JSC “Kazgeologiya”, which held preliminary talks with the companies.

 

 

 

 

 

 


Geophysics indicates conductive core at Mary March in Central Newfoundland

Posted by on Wednesday, 26 March, 2014

Canstar Resources  provides an update on the current exploration activity for its Mary March Project, located near Buchan’s Junction in Central Newfoundland.
The Company’s recent borehole geophysical program conducted on holes drilled during 2013 has provided results that distinguish a high priority drill target near the Mary March massive sulphide zone. All of the holes surveyed clearly point to a more conductive zone downdip and to the east of holes MM13-29 and MM13-30, suggesting the mineralization is open for expansion in these directions.

 

 

 

 

 

 

 

 

 

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The Mary March zone is the initial discovery area drilled by Phelps Dodge in 1999 where they encountered impressive grades of 10.1% Zn, 1.68% Pb, 0.64% Cu, 122.1 grams per tonne (g/t) Ag, and 4.2 g/t Au over 9.63 meters. The drilling completed by the Company in the Mary March area successfully added to these results, encountering massive sulphide zones with two separate holes. In drillhole MM13-30, 11.6 meters of mineralization containing 3.6% Zn, 0.1% Cu, 0.8% Pb, 25 g/t Ag, and 1.5 g/t Au; including a 3.6-meter high-grade zone containing 7.5% Zn, 0.04% Cu, 1.37% Pb, 26.1 g/t Ag, and 1.7 g/t Au, and extended the Mary March Zone to depth. In MM13-29, 5.0 meters of mineralization was encountered, containing 4.82% Zn, 0.38% Cu, 1.04% Pb, 71.3 g/t Ag, and 1.8 g/t Au, including 3.5 meters of 6.21% Zn, 0.13% Cu, 1.42% Pb, 82.8 g/t Ag, and 1.9 g/t Au (see Company Press Release dated January 21, 2014).
Results for surveys completed for holes in the Nancy April area, which is located approximately 500 meters southwest of the Mary March zone require more data and investigation, remaining relatively underexplored compared to the Mary March zone.

“This is exciting news for our shareholders and for the Mary March project,” stated Danniel Oosterman, President and CEO of Canstar. “In an area where mineralization is known to give weak responses, we are encouraged to find such an obvious anomaly offhole to known mineralization. Needless to say the company regards this as a high priority target for its next drilling program.”


Strong EM Targets Have Been Detected Downhole Geophysics at Yepleu and Samapleu Deposit

Posted by on Monday, 24 March, 2014

Sama Completes Downhole Geophysics on Five Drill Holes at Yepleu and Samapleu Deposit (West Africa); Strong EM Targets Have Been Generated

Sama Resources Inc./Ressources Sama Inc. announces the completion of the Downhole Electromagnetic Geophysical (“DHEM”) survey on five (5) holes at the Samapleu and newly discovered Yepleu nickel-copper-palladium Deposits in Côte d’Ivoire, West Africa.

Abitibi Geophysics Inc. from Val d’Or in Canada performed the survey and the interpretation is performed by Mr. Daniel Card, Senior Geophysicist for Southern Geoscience Consultants, Australia.

Three holes were surveyed at the Yepleu deposit, one hole at the Samapleu Main and one hole at the Samapleu Extension 1 deposits.

Preliminary inspection of the data indicate strong Electromagnetic (“EM”) responses on all holes surveyed. Detailed interpretation and modelling is in progress for the following geophysical anomalies:

 
Hole         Location       Response: Depth from surface in meters ("m") 
SM34-570407  Extension 1    - EM anomaly at around 280-320 m 
SM44-525290  Samapleu Main  - EM anomaly at around 150 m 
YE31-637117  Yepleu         - EM anomaly at around 120 m 
YE31-694543  Yepleu         - EM anomaly at around 160 m 
YE23-398223  Yepleu         - EM anomaly at around 40 m

“The survey was performed extremely well by Abitibi Geophysics,” stated Dr. Marc-Antoine Audet, President and CEO. “We look forward to some very good drilling targets from the modelling.” “We are working on this as top priority,” added Mr. Card, Senior Geophysicist for Southern Geoscience Consultants.

The Yepleu discovery is located 18 kilometers (“km”) southwest of the Samapleu nickel-copper-palladium deposits. Regional geological mapping has identified that the geological host of the newly discovered Yepleu nickel-copper-palladium mineralization extends beyond the original 3 km by 600 to 800m to an area as vast as 6 km x 4 km (Refer to News Release dated February 03, 2014).

A total of 18 diamond drilling holes for 3,320m were drilled at the Yepleu discovery testing the large sub-horizontal mineralized layer associated with pyroxenite, gabbro-norite and diorite units been part of the newly identified and described Yacouba Layered Complex (Gouedji et al., submitted to Bulletin de la Société Géologique de France (BSGF), January 24, 2014). Exploration results for all drilled holes at Yepleu will be announced in a subsequent press release.

Exploration Model and Targets

Exploration to date has focused mostly on shallow targets (<150m) at the Samapleu and Yepleu deposits. Sama believes that mineralization at the Samapleu deposits could plunge deeper and could extend laterally as suggested by responses obtained from the Helicopter Electromagnetic survey completed in January 2013 and by the current DHEM survey.

At Yepleu, the Company is chasing embayments or structural features that would have trapped mineralised pyroxenite within the sub-horizontal layered complex assemblage.

The technical information in this release has been reviewed and approved by Dr. Marc-Antoine Audet, P.Geo and President and CEO of Sama, and a ‘qualified person’, as defined by National Instrument 43-101, Standards of Disclosure for Mineral Projects.

For more details, the reader is invited to review Sama’s updated compilation on its website at: http://www.samaresources.com/i/pdf/Sama_Corporate_Presentation.pdf

 

amapleu Project

“Samapleu poly-metallic deposits will give Sama the opportunity to become the first poly-metallic producer in West Africa.”

The Samapleu deposit is comprised of disseminated and semi-massive to massive sulphide mineralization hosted by a mafic-ultramafic intrusion located in the southern border of an early Proterozoic age deformation zone affecting the Archean Charnockitic shield. Mineralization is strata bound within pyroxenite layers of the Samapleu mafic-ultramafic complex.

The disseminated mineralization is typically characterized by fine isolated grains to large granular aggregates of iron, nickel and copper sulphides. Sulphide phases observed so far include pyrrhotite, chalcopyrite, pentlandite and minor pyrite. Pentlandite occurs as inclusions in pyrrhotite. Disseminated sulphide occurs as fine grains of 0.5 to 1 mm in diameter, showing a high ratio of pyrrhotite versus chalcopyrite. Sulphide veinlets and fine filaments are also present. Composite grains of sulphide material are dominant, forming sulphide masses of odd shapes ranging from a few millimeters up to several centimeters in any one dimension.


Exploration on Éléonore Gold project, Québec

Posted by on Friday, 14 March, 2014

Midland Exploration Inc.  reports the beginning of its exploration activity on its 100% owned James Bay Éléonore Gold project located in James Bay, Québec. The first phase of the 2014 exploration program consists of a helicopter airborne magnetic geophysical survey over the Éléonore Centre property.

The Eléonore project, which encompasses the Éléonore Centre and West properties, is constituted of a total of 247 claims covering 128 square kilometres, and is located approximately 30 kilometres southwest from and in a geological environment similar to Goldcorp Inc.’s Éléonore deposit. This world-class gold deposit contains reserves of 4.03 Moz Au (proven and probable categories), combined measured and indicated resources of 4.84 Moz Au and inferred resources estimated at 4.10 Moz Au. (Source: Goldcorp press release dated February 13, 2014).

Prospecting conducted by Midland from 2009 to 2013 on the Éléonore Centre property identified the presence of several gold showings associated with quartz-tourmaline pyrite bearing veinlets occurring in sheared metasediments, as well as mafic and felsic metavolcanics which returned up to 18.8 g/t Au. These results strongly suggest that an auriferous hydrothermal system is present on the property by a strong abundance of quartz-tourmaline veins over a plurimetric area. In addition, the 2013 ground induced polarisation (“IP”) survey identified many north-south trending IP anomalies and several remain unexplained. The 2011 soil geochemistry survey permitted to delineate a series of As-Cu-Sb anomalies clustered along a north-south-trending axis. Finally, a series of parallel northeast trending AeroTEM II conductors were outlined by the 2010 airborne geophysical survey which targeted sulfide bearing Éléonore-type sediments on the northern part of the Éléonore Centre property. Some of these conductors coincide with uncovered gold-bearing disseminated to semi-massive sulfides zones identified by Midland and several EM anomalies still remain unexplained.

A high definition airborne magnetic survey covering the Éléonore Centre property was just completed, including the area covered by the 2013 IP survey. The results and interpretation of this survey, totalizing 386 linear kilometres, are pending. Furthermore, preparation for the upcoming 2014 summer exploration program on the Éléonore Centre property currently underway.

Location:

  • The Eleonore property is located about 450 kilometres north of the town of Matagami, in the Opinaca Reservoir area, James Bay, Quebec.

Property:

  • The Eleonore property consists of two claim blocks (Centre and West). The Centre Block consists of 121 claims covering a surface area of about 63 square kilometres, whereas the West Block consists of 109 claims covering about 57 square kilometres. The two blocks are located about 30 kilometres southwest of the Roberto deposit on the Eleonore property held by Goldcorp, where measured and indicated resources are estimated at 3.15 million ounces of gold and inferred resources at 6.25 million ounces of gold.

Highlights:

  • Covers a major N-S-trending structure between metasedimentary rocks and metavolcanic rocks interpreted as the extension of the structure occurring near the Eleonore gold deposit.
  • Prospecting work has uncovered many new gold showings associated with metasedimentary rocks (conglomerates and greywackes):
    • Golden Gun showing: 18.8 g/t Au, 13.6 g/t Au, 0.76 g/t Au
    • Golden Gun West showing : 1.69 g/t Au
    • Aston Martin showing : 1.63 g/t Au
    • Gold Finger showing: 1.01 g/t Au, 0.82 g/t Au
    • Golden Eye showing: 1.90 g/t Au, 0.90 g/t Au
    • Casino showing: 0.76 g/t Au, 0.64 g/t Au
  • Located along a regional metamorphic gradient, typical of the contact between the La Grande and Opinaca groups.
  • New soil (humus) geochemistry anomalies identified in the south part of the Eleonore Centre Block.