Posts Tagged MT

Unlocking Australia’s hidden mineral potential with geophysics

Posted by on Friday, 1 August, 2014

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.”


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.


The new MT anomalies near Paulatuk, Northwest Territories

Posted by on Tuesday, 10 December, 2013

Darnley Bay Resources Limited (“Darnley Bay” or the “Company”) announces the discovery of two new large magneto-telluric (MT) anomalies at its 100% owned Darnley Bay Property, located near Paulatuk, Northwest Territories. Like the first MT anomaly – reported (see October 13, 2013 press release), the new anomalies are spatially coincident with previously-discovered gravity anomalies, are considered good to moderate conductive zones and appear to be hosted by prospective Proterozoic rocks. They are located respectively two and twelve kilometres east of the first MT anomaly.

Darnley Bay received the latest 3D inversion results from EMpulse Geophysics Ltd, the geophysical contractor. The new inversions not only used the magnetic field tipper data, but also included static shift analysis to minimise near surface geologic noise and to better image the apparent resistivity distribution at depth (see EMpulse web site for more details http://www.empulse.ca/).

The MT survey was performed in August 2013 and consisted of a total of 73 line-kilometres, with stations every 500 metres, over three different lines (North, South and East). See http://www.darnleybay.com/news/Figure_1.html andhttp://www.darnleybay.com/news/Figure_2.html, 1:250,000-scale plan views, showing the location of the surveyed lines and of the MT anomalies over gravity and magnetic models backgrounds. http://www.darnleybay.com/news/Figure_3.html is a stack of three vertical profiles along the North Line; the two upper profiles show the MT anomalies over a gravity and a magnetic models background; the lower profile show the MT anomalies over a 2D geological model that honours the gravity, the magnetic and the seismic data of this sector. The new 3D-inversion model revealed:

  1. On the North Line, 12 kilometers east of the first anomaly, a 1.5×3.5 kilometres anomaly with a maximum thickness of 800 metres, its center being at elevation -2,000 metres (below sea level), It is considered to be a moderate to good conductive zone with apparent resistivity values ranging from 32 to 8.9 Ohm-m
  2. On the North Line, two kilometres east of the first anomaly, a 1.0 x 2.0 kilometres anomaly with maximum thickness of 600 metres, centered at elevation -1,300 metres with apparent resistivity between 32 Ohm-m and 15.1 Ohm-m
  3. On the South and East Lines, three weaker anomalies (80 to 45 Ohm-m), with dimensions of 1.0×1.0-3.0 kilometres between elevations -1,000 to -2,400 metres.

The extent, depth, conductivity and the geological setting of the three MT anomalies on the North line fit the metallogenic exploration models Darnley Bay is exploring for: either a copper-nickel magmatic model (example: Sudbury in Ontario or Noril’sk in Russia) or an Iron Oxide Copper Gold model (example: Olympic Dam in Australia).

“I am pleased by these latest results,” says Jamie Levy, President of Darnley Bay, “we now see two new conductive magneto-telluric (MT) anomalies, along with our previously announced anomaly, on the North line. In addition, three less conductive MT anomalies have been interpreted on the East and South lines. We believe the north line has identified priority drill targets with favourable geological and geophysical settings.

The Darnley Bay Property covers a total of 456,000 hectares with a series of mineral concessions and prospecting permits obtained from the Inuvialuit Regional Corporation and the Canadian Government. The Property encompasses what is considered one of the largest and strongest coincident regional gravity and magnetic anomalies in the world with dimensions of 80 x 100 kilometers. The regional gravity anomaly has absolute amplitude of 132 mGal (milli-gals), while the magnetism reaches 1,350 nT (nano-teslas). Darnley Bay staff believes the source of this anomaly is a large and deep mafic-ultramafic intrusion, the type underlying other base metal mining camps, with the potential for mineralization being at shallower depth than the main intrusion itself. It is thought that it was formed during the regional Franklin or the Mackenzie magmatic events, both Proterozoic in age (720 million years and 1,270 million years respectively).

Magneto-tellurics is a geophysical method of imaging the Earth’s subsurface by measuring natural variations of electrical and magnetic fields at the Earth’s surface. In the 1990′s, MT was successfully used to locate mineral deposits as deep at 1,750 metres in the Sudbury nickel mining camp. In the last 10 years, the technique has seen many improvements, particularly with the development of modern 3D inversion. In the oil industry, it is now routinely used, in conjunction with seismic, to better define deep drilling targets.

At the Voisey’s Bay nickel mine, magneto-telluric survey data detected the nickel-copper mineralization at depth, with apparent resistivities between 10 and 25 Ohm-m (http://www.cemi.utah.edu/appls/mt/) similar to the range of values of the three MT anomalies detected on the North line last August on Darnley Bay Property. Resistivity from the Darnley Bay MT anomalous zones may decrease once the final processing of additional low frequency data is completed. Readers are cautioned that the similarity of the survey results is not necessarily indicative of mineralization on the Property. The magneto-telluric method only measures variations in resistivity in the earth and MT anomalies can also be caused by variations in resistivity due to large scale variations in lithology, structure, and/or conductivity of disseminated minerals or pore fluids as in sedimentary rocks. However, the fact that all the anomalies detected so far are closely related to gravity anomalies (http://www.darnleybay.com/news/Figure_1.html and http://www.darnleybay.com/news/Figure_2.html) suggests that the MT anomalies could be produced by denser material than the surrounding rocks; metal-rich lithologies and/or alteration zones being possible sources.

Darnley Bay is waiting for more results from EMpulse; particularly the processing and inversion of the extended bandwidth time series (to 1Hz) that should provide information to depth of 3 to 5 kilometres. Darnley Bay is planning to do more detailed MT surveying on each side of the North line, in order to better define the attitude and orientation of the anomalies for an eventual drilling program. Darnley Bay is also planning more MT surveying over other selected areas on the Property.

The 2013 MT survey on the Darnley Bay Property was performed by EMpulse Geophysics Ltd, from Dalmeny, Saskatchewan (http://www.empulse.ca/). The technique used for this survey is Transient Audio-Magneto-Telluric, with proprietary SFERIC II instrumentation and Adaptive Polarization Stacking algorithm. David Goldak, M.Sc. (Physics), President of EMpulse Geophysics, was in charge of the survey in the field and responsible for the 3D-inversion and the data processing. The technical information of this Press Release has been prepared, reviewed and approved by Mr. J. Gauthier, P. Eng., P. Geo., the Qualified Person as defined by National Instrument 43-101.

The Company is very pleased to announce the hiring of Alan King as a senior technical adviser. Mr. King is a geophysicist who most recently served as the Chief Geophysicist for Vale’s global exploration operations. Alan holds a B.Sc. in geology from the University of Toronto and a M.Sc. in geophysics from Macquarie University. Mr. King has worked as a geophysicist in exploration and resource development globally, including in Canada, Australia, and Brazil, since 1976. Mr. King has been involved in the application of geophysics in mining, oil sands development and environmental applications for a variety of commodities. Mr. King currently acts as a geophysical consultant through Geoscience North.


Seismic, gravity and magnetotelluric dataset from Geoscience Australia

Posted by on Thursday, 31 January, 2013

The final seismic, gravity and magnetotelluric dataset from Geoscience Australia’s Onshore Energy Security Program has been processed and released.

The data were acquired in 2011 by Geoscience Australia in conjunction with the Geological Survey of Western Australia (GSWA) as part of the Western Australian Government’sRoyalties for Regions Exploration Incentive Scheme. The 484 kilometres of data were obtained over the Yilgarn Craton, Officer Basin and Musgrave Province of Western Australia. This survey will provide precompetitive data for energy and mineral exploration, and for potential water resources. These data, combined with the 2001 Northern Yilgarn Survey, and the 2010 Capricorn and Youanmi Surveys result in a complete cross section of central Western Australia.

Overall, more than 6500 kilometres of deep crustal seismic data were acquired during the Onshore Energy Security Program, providing valuable structural information for the Australian crust from the near surface to the Moho, boundary between the Earth’s crust and the mantle. As well as providing precompetitive data, the surveys have helped to expand understanding of the complex structures and geology of the Australia continent.

The processed SEGY data, images and ancillary information are now available for free download.

Interpretation of the seismic and magnetotelluric models undertaken by GSWA and Geoscience Australia geoscientists will be presented at a public workshop in Perth in June 2013.


Geophysical Survey Indicates Continuity of the Deep Conductivity

Posted by on Tuesday, 12 July, 2011

Romios Gold Resources Inc. announces the results of a recent ground geophysical survey carried out on the Trek Property in Northwestern B.C, Canada. The ground survey identified a deep conductivity anomaly at approximately 300 metre depth that may be a continuation of a large, anomalous conductive zone previously identified by the Titan 24 geophysical surveys (see Press Release dated November 4, 2010).
The 2011 ground geophysical survey, carried out by Frontier Geophysics of Vancouver, B.C., was oriented in an east-west direction parallel to previous ground surveys along the southern margin of the North Zone. The survey, herein referred to as the North Zone Line 4, comprised induced polarization (IP), resistivity (RES), and ground magnetics (MAG) readings every 100 metres for a total survey length of 1.4 kilometres with 100 metre-spaced dipoles. Additional ground surveys were postponed due to high snow levels.

The IP profile from North Zone Line 4 indicates a large, 200 metre-wide conductive anomaly at 300 metres depth below the center portion of the line. This zone of high conductivity exists at approximately the same elevation and exhibits an identical width and geophysical signature (100-500 ohm / metre) as all three of the MT conductivity anomalies identified in the three Titan 24 lines to the north. The conductivities measured on North Zone Line 4 are also higher overall (less resistive) than others in the area.

The IP profile from North Zone Line 4 also correlates with the Titan24 lines to the north. Line 4′s IP profile indicates three zones of anomalous chargeability. The eastern-most IP anomaly correlates with IP anomalies to the northwest in the area of the current drilling at the North Zone. One of the western-most IP anomalies, lying along the surface, correlates with large amounts of sulphides in outcrop. The other western anomaly, extending from surface to 350 metres depth along the western edge of the survey, indicates a different rock type along a major fault.

Silver Standard Consolidated collected four rock samples within the area in 1989. These samples were taken from the area immediately adjacent to the middle of Line 4, in the area of moderate and high conductivities (low RES) and moderate chargeability (IP), similar to the geophysical signatures from the mineralized areas further north. Rock sample results (shown in Table 1 below) include samples 333215 and 333216, reportedly assayed 2.04 % Cu, 0.70 g/t Au, and 13.2 g/t Ag, and 4.32 % Cu, 1.0 g/t Au, and 36.2 g/t Ag, respectively.


Completion Of Airborne Geophysical Survey In Northwestern British Columbia

Posted by on Thursday, 23 June, 2011

Romios Gold Resources Inc.  announces the completion of a 743 line-kilometre airborne geophysical survey over the Company’s wholly owned Dirk and Andrei properties in the Galore Creek area, Northwestern British Columbia. The geophysical survey employed Fugro Airborne’s “DIGHEM” system, measuring multiple frequency electromagnetic fields to produce high-resolution electromagnetic resistivity and magnetic anomaly maps of the top 150 metres of the earth’s crust. The DIGHEM system, in development and use for over 40 years, is widely used in the mining and exploration industry and has aided mineral exploration at other properties in the area such as Newmont Lake, Trek, Galore Creek, and Copper Canyon.

Preliminary results of the Fugro survey over the Dirk property suggest a coincidence between a broad, northeasterly striking magnetic anomaly of moderate intensity with a megacrystic syenite porphyry, similar to those found at Galore Creek. Surface mineralization on the Dirk property is reflected as geophysical anomalies exhibiting a high-magnetic, low-resistivity signature within and adjacent to a larger magnetic anomaly outlined in the Fugro Airborne Survey. Together, the broad magnetic anomaly and the anomalies reflecting surface mineralization, cover an area approximately 9.6 km long by 3.0 km wide. A 2010 mapping project from the British Columbia Geological Survey (BCGS) supported Romios’ contention that the Dirk property mineralization is analogous to and may be as large as the Galore Creek Project.

The Dirk and the recently staked Andrei property are described by the BCGS as holding the potential for VMS (volcanic massive sulphide) – related mineralization. Known silver, zinc, and copper- mineralization within rhyolite ash flows on the Andrei property are manifested in the Fugro surveys as geophysical anomalies which exhibit low to moderate resisivity and moderate magnetic signatures similar to those recorded over the National Instrument 43-101 Inferred Resource of the Northwest Zone on the Newmont Lake property.

A more comprehensive analysis of the Dirk and Andrei geophysical surveys will be conducted upon receipt of the completed and final results from Fugro Airborne Surveys. Maps of the preliminary results will be posted on Romios’ website.

The airborne geophysical survey is part of the $6+ million 2011 exploration program which also includes approximately 10,200 metres of diamond drilling on the Trek property, 1,200 metres on the Dirk property, and 400 metres on the Newmont Lake property.

Drilling commenced on June 2, 2011 on the Tangle and North Zones at the Trek Property. The first hole has been completed on the Tangle Zone and has encountered variable amounts of sulphide mineralization. This mineralization correlates well with the IP (induced polarization) and MT (magnetotelluric) anomalies identified in the 2010 Titan 24 Survey. Drilling on the second hole on the Tangle Zone is in progress.

Drilling has also commenced on the first hole of the 2011 season in the North Zone targeting the near surface mineralization and the deeper MT anomaly identified by the 2010 Titan Survey. All drilling results will be announced as soon as they are available.


Geophysical Survey at Lutila Gold Licence, Slovakia

Posted by on Tuesday, 14 June, 2011

Ortac Resources Ltd, exploration and development company focussed on precious metal projects in Europe, announces the commencement of a ground based geophysical survey over the northern section of its 63 km sq Lutila Exploration Licence Area (‘Lutila’) to generate gold mineralised targets for follow up drilling.  Lutila is part of the Company’s flagship Kremnica Gold Project in Central Slovakia and is contiguous to the Kremnica Mining Licence Area, which has a current JORC resource of 1.1 million ounces of gold equivalent, and is being fast-tracked towards production.

The Titan 24 ground based geophysical survey will be conducted by Quantec Geoscience Ltd (‘Quantec’) and will consist initially of three survey lines, totalling 7.2km each, of direct current, induced polarisation and magnetotelluric resistivity data acquisition.  Each Titan 24 line will be approximately 2.4km long with each survey line having the ability to acquire data over a 100m wide zone.  All field data will be compiled, processed and interpreted by experienced professionals at Quantec’s Interpretation Centre in Toronto, Ontario.

Ortac CEO Vassilios Carellas commented, “This geophysical survey represents our initial phase of work focussed on the exploration of the wider Kremnica Gold Project, which we believe has the potential to house a gold equivalent resource in excess of 2 million ounces.

“The previous work carried out at Lutila has indicated that the gold mineralisation may be of a similar style as that at the Kremnica deposit, which we are currently fast-tracking towards production.  Any Kremnica-type vein potential at Lutila is believed to be hosted in the underlying andesitic volcanic sequence, as at Kremnica, rather than in the surface outcropping rhyolites, therefore this Titan 24 ground based geophysical survey will be highly valuable in identifying economic mineralised targets for drill testing.”

Geology & Structure

The geology of the Kremnica gold deposit is well established. The Šturec zone is continuously mineralised for 1,200 m along strike, is typically 100 to 150 m wide and extends to a known depth of at least 300m. The main part of the Šturec zone is the Schramen Vein, which is up to 100 m wide along a 500 m strike section and accounts for some 90% of the gold contained in the Kremnica measured and indicated resources.

It is a massive to sheeted quartz vein that strikes almost due north, generally dips steeply to the east, and thins to the north, south, and at depth. Some additional exploration is required to clarify the extent and continuity of hanging and footwall mineralisation in the Šturec zone.


Substantial geophysical survey in Chile

Posted by on Monday, 20 December, 2010

SAMEX is conducting a multi-project, multi-faceted exploration program at its large, wholly owned Los Zorros property holdings in Chile. Thus far, three core drill holes have been drilled and a fourth hole is in progress. SAMEX recently secured major funding which has facilitated a significant expansion and extension of the exploration programs on its various projects. While core drilling is ongoing, the Company is also preparing for a substantial geophysical survey over large portions of the Los Zorros district utilizing the Titan 24 proprietary deep-earth-imaging technology from Quantec Geoscience.

Following is an overview of the exploration progress and planned activities for various projects at Los Zorros:

Cinchado Gold Project – Three core holes have been drilled thus far. Data evaluation is ongoing and a Titan 24 survey line has been prepared to cross over the project area and results will be incorporated together with all mapping, sampling, drilling and historic data to guide additional drilling in the Cinchado Project area.

Titan 24 Geophysics - The Titan 24 Magnetotellurics and IP/Resistivity is a deep-earth-imaging technology system that images conductive mineralization, disseminated mineralization, alteration, structure and geology for targeting of drill holes to depth. Grid-lines are currently being surveyed-in for the geophysical program scheduled to begin in January 2011. Data from the Titan 24 survey will be correlated with data from drilling to help guide exploration throughout the extensive Los Zorros district.

The Los Zorros property contains numerous large-sized gold and gold-silver-copper targets on a single property holding and thus represents a very important, strategic opportunity for SAMEX. The prospect is geologically well situated within the highly prospective mining belt that contains the copper-gold ore bodies of the Punta del Cobre District (150 million cumulative tonnes with an average grade of 1.5% copper, 0.2 to 0.6 g/mt gold, 2 – 8 g/t silver), the large Candelaria mine (460 million tonnes containing 0.82% copper, 0.22 g/mt gold, 3.1 g/mt silver), the large, mined-out Chanarcillo silver deposit (+100 million ounces of silver), plus many smaller copper-gold and gold ore bodies which still locally support mining operations. Infrastructure for large mining activity is readily available in the area with power, transportation, water, communications and manpower all within advantageously close distances. Because of the large size of the property, and the fact that our exploration is still in progress, the information and ideas behind the targets currently being developed must be considered as an evolving picture. The possibility of defining further new target(s) on the property remains strong.


The new porphyry target at 0.5 km depth

Posted by on Thursday, 4 November, 2010

Romios Gold Resources Inc. announces the results of the Titan 24 geophysical survey carried out by Quantec Geoscience (Quantec) during August 2010 on its Trek Property in the Galore Creek area in north-western British Columbia. The objective of the survey was to map and detect porphyry mineralization at depth targeting the North and Tangle Zones. Titan 24 surveys have been a part of the successful identification of porphyry ore bodies and extensions of known ore bodies at other locations in British Columbia. The surveys measured the resistivity (DC), induced polarization (IP), and magnetotelluric (MT) properties of the underlying rock.
Highlights of the Survey:

  • The survey identified a large deep conductor 500 metres long, 300 metres wide and 200 metres high across all three lines in the North Zone. This conductor remains open to the North and the South. This new feature, which lies east and below the previous drilling and occurs from 500 to 675 metres below surface, represents the main target for future drilling. The conductor provides an opportunity for significant added tonnage to the North Zone.
  • The analysis and interpretation of the DC, IP and MT results also identified several chargeable anomalies above the deep conductive zone. These anomalies coincide reasonably well with the results of the existing 23 drill holes on the North Zone. The Company intends to continue drill testing these anomalies in its next drill program.
  • On the Tangle Zone, three pronounced IP anomalies were identified along the profile. These are located above a deep conductive zone which is the main drill target in the Tangle Zone. The IP anomalies and the deep conductor correlate well with grab sample assays and a significant soil copper-gold geochemical anomaly. Romios intends to drill this zone in its next drill program.

Tom Drivas, the President of Romios Gold, states, “We are very pleased with the results from the Titan 24 survey. The upper level results correlate well with the drilling at the North Zone, but what is even more exciting is the new large deep anomaly below our drilling to date which may represent the main porphyry body thought to be the source of the upper level mineralization. The survey results at the Tangle Zone are particularly encouraging as they correlate strongly with high copper-gold soil geochemistry. Romios intends to drill-test the new targets which have the potential to host significant incremental copper-gold porphyry mineralization on Trek.”

North Zone – Line 1
This 1.2 kilometre line extended from east of the known mineralization to the collar of TRK08-05. The results of the survey clearly indicate a two conductive layer structure separated by a resistive sub-surface layer. The deep conductive zone, which also extends through lines 2 and 3, is the main target as it may represent the main porphyry system. The results also indicate a large high chargeability anomaly near hole TRK08-05 that correlates with high content of pyrite, and four small IP anomalies that may represent alteration zones. One large high chargeability anomaly at approximately 250 metres depth may correlate to a possible fracture zone and is located near drill holes TRK08-01, 02, 03 and TRK 09-06 which contain mineralized porphyry occurrences with significant copper-gold mineralization. This anomaly is located at the edge of the profile and cannot be completely resolved by the inversion of the data.

North Zone – Line 2
The second and northern-most line transects the North Zone 500 meters north of Line 1. Line 2 extends from east of the known mineralization westward to terminate 150 meters northwest of TRK10-04. This line displays a zone of high conductivity north of TRK10-04, untested by drilling. Other areas of moderate-high conductivity at the North Zone are associated with copper mineralization. The upper resistive layer is sectioned by two main conductive zones. The main deep conductive zone appears on Line 2 at a depth of 600 metres. A weak IP chargeability anomaly appears near the main conductive anomaly at 250 metres depth and may represent potential alteration or mineralization. Drill holes TRK10-03, 10-05 and 10-06 encountered mineralized porphyry dykes above this zone and confirm the zone’s exploration potential.

North Zone – Line 3
The third Titan 24 survey line was placed between Lines 1 and 2, and transects the center of the North Zone from east to west. Generally, the IP and DC patterns reflect those in Line 1. Three high chargeability anomalies can be identified on this profile. A large IP anomaly on the west side of Line 3 correlates with zones of copper-gold-silver mineralized breccias. The first high chargeability may correspond to a near surface anomaly. The second high chargeability is approximately at a depth of 300 metres and remains to be drill tested. The third high is at 300 metres depth on the west side of Line 3 and correlates with zones of copper-gold-silver mineralized breccias. This IP anomaly dips to the east, mirrors a zone of moderate conductivity, and joins with a significant MT anomaly at 500-650 meters depth, interpreted as being the main deep conductive zone displayed on Line 1 and 2. Drill holes TRK10-07 and 10-08 also encountered mineralized porphyry dykes above this zone and further confirm the zone’s exploration potential.

Tangle Zone – Line 4
Three high chargeability anomalies located at approximately 100 metres depth are above a deep conductive zone which appears to extend from 400 metres to 600 metres depth. Results from each of the DC, IP, and MT surveys transecting the Tangle Zone indicate interconnected conductive anomalies that extend from surface to 600 meters depth. At surface, the conductive anomalies correlate with a 700 x 200 metre-wide area highly anomalous in copper and gold derived from gridded soil sampling. Outcrops in the vicinity of the conductive anomalies and soil anomalies contain bornite and chalcopyrite mineralization in porphyry intrusive. Grab samples assayed up to 9.6 g/t Au, and 16.45% Cu with 7.56 g/t Au. Soil sampling in the area assayed up to 5.31 g/t Au and 12.2% Cu.

Titan 24 Survey Parameters
The Quantec Titan 24 DC, IP and MT system is a state of the art geophysical tool used to explore for copper-gold mineralization. Four 1.2 kilometre-long lines, three transecting the North Zone at 250 meter spacings and one transecting the Tangle Zone, were completed at Trek. Each line was surveyed using a dipole-dipole configuration with a dipole size of 50 metres and measured the resistivity (DC), induced polarization (IP), and magnetotelluric (MT) properties of the underlying rocks. The Titan 24 system is capable of measuring properties simultaneously and comparing them to ensure accuracy. The system’s high-resolution digital signal processing and data multiplicity within the array and over time detects and resolves smaller signals from deeper targets while filtering noise. At these line lengths, the Titan surveys permit reliable, high-resolution analysis from surface to 400 meters depth for DC and IP, and down to 1,000 metres for MT. Inversion of the DC and IP data was completed using the UBC3D inversion code.

You can view the geophysical cross sections showing the Titan 24 survey results at the North and Tangle Zones by visiting the following location on the web: http://www.romios.com/s/Trek.asp


SIGMELTS – a freely available software for electrical conductivity calculations in geology

Posted by on Sunday, 3 October, 2010

SIGMELTS is a software that aims at facilitating the modelling of the electrical properties of geological materials. It is based on electrical measurements from the literature performed on silicate liquids, carbonatites, minerals and mantle materials. The bulk conductivity of a two-phase material is proposed on the basis of various existing geometric models. This software is a tool that estimates the electrical response of a geological material at defined conditions. SIGMELTS also provides a “reverse” application, proposing to interpret a conductivity value in terms of storage conditions. This software enables to discriminate the effect of different parameters on the bulk conductivity of magmas, such as the temperature, the pressure, the composition, the water content, the oxygen fugacity and the crystal content. A major point of the philosophy that led to create SIGMELTS is the need for geophysical studies to use electrical measurements in laboratory in order to improve the interpretation of detected magnetotelluric anomalies.


IP Survey Expands Potential of Schaft Creek Deposit

Posted by on Monday, 16 August, 2010

Copper Fox Metals Inc.  provides an update on the results and interpretation of the Quantec Geosciences Ltd. “State of the Art” Quantec Titan-24 DCIP and MT geophysical survey, on the Schaft Creek copper-gold-molybdenum-silver deposit located in Northwest British Columbia.

Highlights:

  • the Induced Polarization/Resistivity (IP) anomalies outlined by the Survey strongly suggest that the Schaft Creek mineral deposit extends a significant distance to the east and at depth beyond the limits of the current diamond drilling,
  • the Survey indicates that the IP anomalies that correspond to the Main, Paramount and Breccia Zones of the Schaft Creek mineral deposit are open to the north and south, and
  • the Induced Polarization anomalies outlined in 2008 have been confirmed by the Survey but these responses are interpreted to represent a geological feature, not mineralization.

Mr. Elmer Stewart, President of Copper Fox stated that “Our primary objective is to complete the feasibility study by the end of 2010. If the IP anomalies are an indication of the size of the Schaft Creek deposit, then the deposit is substantially larger than what has been defined to date. A substantial amount of diamond drilling would be required to define the limits of the deposit. Our 2010 diamond drilling program; although not designed for exploration has been adjusted to test the large IP anomaly identified on Section 6361000 under Mount LaCasse”.

Schaft Creek Deposit:
The Schaft Creek mineral deposit consists of three mineralized zones, being the Main, West Breccia and Paramount (see About Copper Fox for resource estimate of the Schaft Creek deposit).

Quantec Titan-24 DCIP and MT Survey:
Quantec Geosciences Limited (Quantec) was retained to further define two Induced Polarization anomalies located in the area of the proposed mill site in 2008. In order to better interpret any anomalies located by the Survey, the scope of the Survey was extended to include the portions of the Schaft Creek deposit where diamond drilling had been completed. The lithologies, sulphide content and metal grades obtained from the diamond drilling completed on the geophysical Sections were used in the interpretation of the geophysical responses obtained by the Survey.

A comparison of the geophysical response for the Null referenced, DC referenced, Resistivity and MT pseudo-sections shows excellent correlation. To view a geophysical model of the Schaft Creek mineral deposit based on the Null reference chargeability click here. A brief discussion of the IP anomalies defined on each Section is presented below:

Section 6361000:
The survey on this line was completed as a west and east portion due to hazardous terrain conditions. On the west side of the line, the IP anomaly is approximately 1,200 m wide and extends to a depth of 750 m. The western 400 m wide portion of this anomaly corresponds to the Paramount/West Breccia Zone where significant copper-molybdenum-gold-silver mineralization has been defined to an average depth of 400 m below surface. The 800 m wide portion of the IP anomaly located east of the Paramount/West Breccia Zone dips to the east under Mount LaCasse, is open at depth and requires testing by diamond drilling.

The east side of Section 6361000 covers the area of the proposed mill site where the two IP anomalies were located in 2008. The Quantec Survey located the 2008 IP anomalies and based on the diamond drilling information and the strength of the geophysical response, these anomalies are interpreted to represent a geological feature, not sulphide mineralization.

Section 6360600:
The IP anomaly is 1,500 m wide and extends to a depth of at least 750 m below surface. The western 550 m wide portion of this anomaly corresponds to the Paramount/West Breccia Zone where copper-molybdenum-gold-silver mineralization has been drilled to an average depth of 500 m below surface. The 850 m wide portion of this IP anomaly located east of the Paramount/West Breccia Zone dips to the east under Mount LaCasse and requires testing by diamond drilling.

Section 6360200:
The IP anomaly is 1,600 m wide and extends to a depth of 800 m at the center of the anomaly. This anomaly corresponds to the Main and West Breccia Zones where significant copper-molybdenum-gold-silver mineralization and has been intersected by drilling to an average depth of 500 metres below surface. The IP anomaly indicates that copper-molybdenum-gold-silver mineralization extend to a considerable depth below the 500 metre level. A 500 m wide portion of this anomaly located east of the Main Zone requires testing by diamond drilling.

Section 6350800:
Two IP anomalies have been located on this Section. The first anomaly is approximately 250 m wide, has a depth of 300 m and requires testing by diamond drilling. The second IP anomaly is 1,450 m wide; has a depth of approximately 600 m on the western side and a depth of 450 m on the east side. The IP anomaly corresponds to the Main and West Breccia Zones where significant copper-molybdenum-gold-silver mineralization has been drilled to a depth of 250 m. The portion of the IP anomaly below the 250 m level requires testing by diamond drilling.

Section 6350400:
The IP anomaly is 1,500 m wide and has an average thickness of 400 m. The western portion of this anomaly measures 300 m wide by 450 m deep and is located at a depth of 200 m below surface (interpreted to be faulted downward). The remaining 1,200 m wide portion of the anomaly is relatively flat lying and has an average depth of approximately 400 m. This anomaly corresponds to the Main and West Breccia Zones where significant copper-molybdenum-gold-silver mineralization has been drilled to a depth of 250 m below surface. A 250 m wide section on the east side of this anomaly requires testing by diamond drilling. The IP anomaly is open along strike to the south.

Quantec Titan-24 Survey Parameters:
The Quantec Titan-24 DCIP and MT system is a State of the Art geophysical tool used to explore forcopper mineralization. The Survey was completed on five lines surveyed by differential GPS instrumentation over the area of the proposed mill site and further to the west over the Schaft Creek deposit where a substantial amount of diamond drilling had been completed. Survey Sections were completed at 100 m station intervals and 400 metre line spacing. A total of 28.2 kms of DC/IP survey line (plus current extensions) and 22 kms of MT data were collected. Magnetotelluric, Resistivity and Chargeability data were collected at 50 metres stations along each Section. The Titan-24 survey typically images DC resistivity to depths of 500-750 m and the IP typically images to 500-750 m, in sub-vertical tabular geologic settings and up to 50% more for sub-horizontal settings. The interpretation of the data was completed by Quantec utilizing the lithology, estimated sulphide content and analytical results from the diamond drill holes completed on or near the geophysical Sections. The 3D inversion of the DC and IP data was completed using the UBC3D inversion code and is shown as Null referenced and DC referenced chargeability. In several cases, not all of the line could be surveyed due to hazardous terrain conditions. The 14 mRad contour on the UBC smoothed, Null Referenced pseudo-section was used to determine anomalous chargeability.


IGT2010 – Innovative Geoscience Technology Conference

Posted by on Thursday, 13 May, 2010

May 19 – Denver, CO.

Special Educational Event – produced by the Denver Geophysical Society

2nd Annual Innovative Geoscience Technology Conference

Where: Hilton Garden Inn, Denver Downtown
1400 Welton Street Denver 80202

REGISTER AT: www.denvergeo.org
Denver Geophysical Society

KEYNOTE SPEAKER: Daniel M. Jarvie Worldwide Geochemistry
title: Geochemical Assessment of Rocky Mountain Shale Resource Plays and Prospects

FEATURED KICKOFF SPEAKER : Dan Likarish Regis University
title: The Use of Virtual Social Networks to Investigate the Influence of Deep Crustal Processes on the Occurrence of Faults and Fractures

Innovative Geoscience Technology Presentations

The Basement-Petroleum Connection: New Insights - M. Swan, MagnaChem Exploration, Inc.

3D Anisotropic CSEM Inversion
- C. Jing, Exxon-Mobil, Inc.

Evidence of Hydrocarbon Seepage Using Multispectral Satellite Imageryin Iraq
- S. Perry, Perry Remote Sensing, LLC

Integrated MT/Gravity Geothermal Exploration in Hungary: A Success Story
- G. Yu, KMS Technologies, LLC

New Aeromagnetic Compilation of Artic, Russia and Europe and its Inversion to Depth of Basement and Structure
- D. Fairhead, GETECH

Hydrocarbon Mapping in Mozambique with Airborne Geophysics

- J. Rudd, Aeroquest Surveys

CO2 Geologic Sequestration Begins and Ends with Geoscience Technology
- W. Row, Schlumberger Carbon Services

Shale Core Analysis Required for Gas Reserve Estimates
- C. Hartman, Weatherford Labs

Locating Abandoned Coal Mines to Assess Risk Using Self-Potential and DC Resistivity, Weld County CO
- K. Bohlen, Colorado School of Mines/ Encana


Magnetotelluric in geothermal

Posted by on Wednesday, 5 May, 2010

On Jan. 20, 2010 Magma Energy Corp. announced that it had been awarded the 100,000 hectare Pellado property, 300 km south of Santiago, by the Government of Chile. Pellado adjoins the Maule property upon which Magma previously reported a 140 megawatt (“MW”) Inferred Resource. Now (5 May) Magma Energy has exploitation permit from the Government of Chile enabling development of a 50 MW geothermal operation on the 4,000 hectare Laguna de Maule (Maule) property, 300 km south of Santiago.

Slim hole drilling and a magnetotelluric geophysical program carried out by Magma in 2009 discovered a large heat anomaly (the “Mariposa Geothermal Resource”) that straddles the Pellado and Maule properties. Magma’s consultant, Sinclair Knight Mertz (“SKM”), estimates that Mariposa contains an Inferred Resource of 320 MW of electrical generation capacity, including the previously reported 140 MW Inferred Resource.

Magma is currently drilling the second of five slim holes wells into the Mariposa Reservoir.  The first well drilled in 2009 discovered temperatures greater than 200╟C at a depth of approximately 650 meters.

The 2010 slim hole program, plus related work, commenced in March and is expected to conclude by December at a cost of US$15 million.  The target depth of each of the four slim holes is 1,500 meters.

The area of the Mariposa Property corresponds to an active volcanic zone. The region is composed of several large super-imposed volcanic structures. Several fumaroles and hot springs are noted around the volcanic systems, evidence of past volcanic activity. Fumaroles are found on the concessions and hotsprings are located nearby. Work done to date suggests the presence of a magma chamber five to ten km in depth that may be the driving force for the geothermal system found in the area. Significant volumes of pyroclastic material constitute the underlying volcanic sequences and may represent potential reservoir rocks.

Schlumberger Water Services completed a geophysical resistivity survey on the Mariposa Property in March 2009. Magma also undertook geological mapping, structural analysis and water and gas chemistry analysis. Gas chemistry indicated high temperature (greater than 230°C) subsurface fluids. The resistivity survey also indicated a very large (greater than 26 km2) anomaly.


Quantec Titan results in Nevada

Posted by on Monday, 26 April, 2010
Boxxer Gold Corp.  announces the results of the Quantec TITAN-24 DCIP/MT survey completed over its 100% owned Boss and Crystal Pass projects located in the Goodsprings Mining District, southwest Nevada. The identified targets combined with the previous exploration results suggest huge potential for the district.
Highlights
 Significant number of targets outlined, most targets open in two directions:
– Boss Extension: 15 targets outlined,
– Crystal Pass: 17 targets outlined;
 Diamond drill program planned to test recently identified targets.
Boxxer’s President and CEO, Elmer B. Stewart, explained, “The results from the Quantec Survey are the single most significant set of data generated from our Boss and Crystal Pass projects in the last 18 months. The number of new targets has moved Boxxer a major step closer to proving the porphyry potential for this district. The large TITAN-24 DCIP and MT
targets coincide with previously identified zones that display conductivity at depth, interpreted intrusives and mineralized skarn, all resulting in the generation of numerous very high quality diamond drilling targets at Boss and Crystal Pass. We are encouraged by the dimensions of the chargeability and resistivity responses in the new target areas interpreted to contain
porphyry copper style mineralization as this is consistent with the porphyry copper model being used by Boxxer to explore the Goodsprings Mining District.”
A total of three high priority targets (high chargeability and conductivity), six moderately-high priority targets (high chargeability and moderate conductivity), 15 moderate priority (high chargeability and resistivity), six moderate-low priority targets (shallow or deep conductivity) and two low priority targets were located over the Boss and Crystal Pass areas. Please see press release dated March 16, 2010, for the parameters of the Quantec Survey.

Results of the 2D inversion of the IP using Null reference data along line L1 (on the top)

Results of the 2D inversion of the MT data along line L1 Boss area (on the bottom)


The March 2010 Newsletter from Phoenix

Posted by on Wednesday, 17 March, 2010

http://www.phoenix-geophysics.com/news/newsletter/?issue=49?

About TXU-30 transmitter which has provided a significant advantage in the ongoing study of HudBay Minerals’ deep.

Discovery Geophysics Inc. of Saskatoon (Canada) used an innovative combination of three TEM components from around the world.

Discovery Geophysics developed the system for uranium exploration in the deepest parts of the Athabasca Basin.

The TXU-30 injected 20 amperes into a 2.7 km x 2.0 km transmitter loop (108 Million amp-m2).

And about Lalor Lake deposit discovery.