To date, Dias has carried out commercial surveys in Argentina, Australia, Canada, Chile, China, Czech Republic, Dominican Republic, India, Kazakhstan, Mexico, Peru, Saudi Arabia and the USA.
Dias Geophysical successfully imaged alteration related to a known uranium deposit from 100 m depth to over 600 m depth. A similar conductive response 400 m south of the known deposit led to the discovery of the South Arrow uranium deposit.
Canada’s Athabasca Basin hosts the vast majority of high-grade uranium deposits. NexGen Energy’s Arrow deposit in Saskatchewan, Canada, is the largest undeveloped uranium deposit in the world. Direct detection of unconformity uranium deposits is virtually impossible with conventional geophysical exploration techniques. The DIAS32 DCIP survey was designed to image the alteration related to the high-grade uranium mineralization at Arrow, and by integration with other geologic and geophysical data sets, improve exploration efficiency.
A full 3D resistivity survey was completed across a 1.4 X 1.4 km area centered over the known deposit. A portion of the survey was completed over a large open-water lake. The multi-azimuth and multi-scale data set was processed and inverted to generate a high-resolution 3D resistivity model of the survey area from surface to 600 m depth.
The DIAS32 survey successfully imaged the alteration related to the Arrow high-grade uranium deposit with a high degree of correlation. A similar response in the data 400 m south of the Arrow Deposit was drill tested and high-grade uranium mineralization was discovered. This discovery of the South Arrow deposit confirms the effectiveness of the resistivity method in the exploration for basement-hosted unconformity-related uranium deposits in and around the Athabasca basin.
VR Resources Ltd.
The Big Ten caldera is a Tertiary-aged volcanic complex approximately 20 km in doameter in west-central Nevada. It occurs in an extensional rhyolite volcanic center that is analogous in age and setting to the Round Mountain Mine.
The Amsel project is one of several project areas within the Big Ten complex. Prior work has defined a 2 km X 3 km airborne radiometric potassium anomaly with a coincident robust Au-Ag-Sb-Mo soil anomaly. These, plus a hilltop of silica-clay altered volcanic tuff with gold-bearing quartz veins points to the potential for a large tonnage epithermal gold system, analogous to the Round Mountain deposit, where mineralization is found below an alteration cap in a welded tuff.
The DIAS32 survey was designed to identify where sulphide-bearing quartz veins are concentrated within the large alteration cap and geochemical anomaly. The 3D CVR survey using 200 m line spacing and 100 m station spacing generated more than 225,000 data records from which a final data set of 95,000 data records were used for 3D inversion modelling. The survey was designed to image to over 600 m depth.
The 3D resistivity model identified a large near-surface high resistivity anomaly covering a 700 m X 900 m area in the southwest quadrant of the radiometric anomaly and surface alteration zone. The high resistivity zone appears to form a cap directly above an underlying IP anomaly. The high resistivity correlates with high temperature adularia and muscovite alteration in rocks, and the strongest multi-element soil geochemical anomaly.
A section along line 8000 through the 3D IP model depicts the chargeability anomaly directly below the high resistivity zone interpreted as an alteration cap. The anomaly extends from surface to a depth of at least 600 vertical meters. The anomaly occurs below the main multi-element soil geochemical anomaly and below the area where muscovite and adularia alteration minerals are identified in rock samples.
The IP anomaly from the 3D inversion model correlated directly with the overlying high resistivity alteration cap. It is also co-spatial with the silver geochemistry anomaly, and with sulfur, because the IP is expected to relate to pyrite associated with secondary hydrothermal silica. The IP anomaly correlated with the strongest sulfur anomaly and is the principal target for pyritic quartz vein stockwork with gold and silver mineralization.
Golden Triangle, BC, Canada
Th Hat Property is situated in the prolific Golden Triangle of northern British Columbia, Canada, which hosts many significant gold and copper deposits. The Hat Property is thought to host an Alkalitic Copper Gold porphyry. The property is structurally complex; generally, the southwestern portion of the property has a large dioritic intrusion which is interpreted to sit on top of Stuhini group volcanics. Soil sampling has outlined several zones of copper, gold and silver near the margin of the intrusion. Historical 2D geophysical surveys have shown the IP method to be effective in detecting mineralization, but limited depth and poor resolution have hampered drill targeting.
In 2018, Dias Geophysical was contracted to carry out a 3D DIAS32 survey across the priority portion of the property. The 9 sq.km survey comprised of 12 lines of 250 m line spacing and 100 m station spacing. The survey was carried out in a pole-dipole configuration with common voltage referencing.
The depth of investigation was designed to be ≥500 m, and high resolution was achieved through multi-azimuthal acquisition. During the QC process, approximately 10% of the DC data and 15% of the IP data were removed, leaving a high-volume data set of over 100,000 data points.
Unconstrained 3D inversions for the resistivity and chargeability parameters produced robust 3D models with a near-surface resolution of 25 m.
The DIAS32 survey identified an extensive chargeability high which occurs below the Lisle Zone, which had yielded encouraging drill results prior to the DIAS32 survey. The DIAS32 3D models were integrated with geological, geochemical and magnetic data sets to produce a prioritized list of targets. The subsequent drill program produced significant results in the Lisle Zone where mineralization was found to occur to depths of over 700 m. Visible gold was encountered in one hole. Drill testing of hole H036 revealed an occurrence of visible gold which was accompanied by chalcopyrite, bornite, and magnetite.
Seabridge Gold Inc.
Northern BC, Canada
Dias Geophysical successfully imaged geological structure, lithology and mineralization at the Quartz Rise project in British Columbia’s Golden Triangle region. A rolling 3D DIAS32 survey images the epithermal vein systems in the near-surface, and when combined with geology and magnetic data, identifies a potential porphyry source at depth.
Three years of exploration work at Quartz Rise have isolated a promising source of the lithocap above the old, high-grade Johnny Mountain Mine. Further geophysical, geochemical and geological mapping surveys have been completed, and an initial grill program totaling up to 8,000 m has been designed to test the large intrusive system that is likely responsible for the lithocap and elevated gold and copper concentration. This area has a geological environment astonishingly similar to KSM.
A rolling 3D survey with CVR was completed over the 1.5 km X 0.8 km survey area with the DIAS32 system. A line spacing of 50 m and a reciever spacing of 25 m provided detailed 3D imaging of the subsurface given the epithermal vein target. The CVR data set provided multi-scale and multi-azimuthal data for 3D inversion. The final 3D resistivity and chargeability models were resolved to 5 m.
The DIAS32 3D survey imaged the vein system and identified an unexpected east-west trend. Drill targeting of the high resistivity features was successful, and analysis of the core identified a breccia vein, which suggests the presence of a proximal porphyry source. A successive DIAS32 survey was completed in 2019 to close out the chargeability anomaly, and integration of this data with geology, geochemistry and magnetic data interpreted a priority target for the potential porphyry source and is currently being drill tested.
Dias Geophysical successfully imaged the geological structure, lithology and alteration related to a known mineralization structure at a depth of 700 m to 900 m. The survey identified an alteration plume emanating up from a mineralized basement fault structure.
Canada’s Athabasca Basin hosts the vast majority of high-grade uranium deposits. The Virgin River Uranium project occurs along a major structural corridor which hosts several world-class uranium deposits. The 2D survey line was completed to demonstrate the depth capabilities of the DIAS32 system in the Athabasca Basin environment. While direct detection of uranium deposits is not possible with geophysical methods, it is possible to image associated features such as the conductive graphite common in the host structures and the alteration plume that often emanates upward into the overlying sandstones.
a 12.5 km 2D line was surveyed with the DIAS32 system across the Virgin River structure. The receiver spacing of 150 m and current injection spacing of 75 m produced a relatively high data volume of 2D data with a-spacings of 150 m, 300 m, 450 m, etc., up to 1,200 m. This multi-scale data set was processed and inverted with the UBC-GIT and Loke RES3DINV codes to generate high-resolution 2D resistivity sections from surface to a depth of 1.2 km.
The DIAS32 2D test survey successfully imaged the alteration related to potential uranium mineralization in an area of the Athabasca basin where the unconformity lies at a depth of 700 m to 900 m. The survey mapped variation in the bedrock beneath the unconformity and hosted unconformity-related uranium deposits.
Alliance Resources Limited
Dias Geophysical successfully imaged geological structure, lithology and mineralization at the Weednanna Gold Deposit in South Australia. A rolling 3D DIAS32 survey images the sulphide mineralization beneath ubiquitous surficial sediments with great clarity and to a depth of over 300 m. The survey generated several high priority targets.
The Weednanna deposit is a magnetite breccia in carbonate altered rocks forming a skarn near the contact with a granite intrusion and containing elevated gold, bismuth, tin, uranium, lead and zinc. High grade gold is associated with sulphide replacement of magnetite. The survey area is covered by a veneer of transported sediments that makes exploration challenging. Prior to the DIAS32 survey, little was known about the potential mineralization below 200 m. The strong association of gold with sulphides makes the IP method an effective tool for imaging potential mineralization.
A rolling 3D survey with CVR was completed over the 1.1 km X 1.5 km survey area with the DIAS32 system. A line spacing of 50 m and a receiver spacing of 25 m provided detailed 3D imaging of the subsurface. The CVR data set provided multi-scale and multi-azimuth data for 3D inversion. The final 3D models of resistivity and chargeability were resolved to 5 m.
The DIAS32 3D survey successfully imaged the mineralized system to a depth of approximately 300 m. The final 3D models of resistivity and chargeability provided insight into structure, lithology and mineralization, and several high priority targets were interpreted from integration of the survey results with other geophysical and geological data sets.
The Laramide belt is a major porphyry province that extends for approximately 600 miles (1,000 km) from Arizona to Sinaloa, Mexico, and hosts a number of world class deposits. The Rosemont deposit, which comprises 869 MT at 0.51% Cu equivalent measured and indicated with a further 128 MT at 0.49% Cu equivalent inferred, falls within this belt.
The Rosemont Deposit consists of skarn-hosted copper-molybdenum-silver mineralization related to quartz-monzonite porphyry intrusions. Genetically, it is a style of porphyry copper deposit, although intrusive rocks are minor within the resource area. The skarns formed as the result of alteration of Paleozoic carbonate and, to a lesser extent, Mesozoic clastic rocks.
Mineralization is mostly in the form of primary (hypogene) copper-molybdenum-silver sulphides, found in stockwork veinlets and disseminations in the altered host rock. Some oxidized copper mineralization is also present in the upper portion of the deposit. The oxidized mineralization occurs as mixed copper oxide and copper carbonate minerals. Locally, minor amounts of enriched, supergene chalcocite and associated secondary mineralization are found in and beneath the oxidized mineralization.
A DIAS32 distributed dipole-pole-dipole array survey was conducted along the section shown above. This 2D DC/IP survey was carried out using 25 receivers along the survey line, all of which are recording for each current injection point. The receivers are distributed along the line with a 100 m spacing. Current was injected every 100 m along the line at the midpoint of each adjacent receiver electrode pair. In this way for each current injection up to 24 dipoles are recorded simultaneously. One of the strengths of this approach is that measurements are being taken in both directions along the line relative to the injection point. The current waveform is a 50% duty cycle square wave with a base frequency of 0.25 Hz, which delivers a 1 s on-time during which we measure the resistivity parameter, and a 1 s off-time during which we measure the induced polarization parameter.
The data were processed and interpreted using the UBC-GIF inversion routine DCINV2D. The inversion accounts for the topographic relief along the survey line, which is important to consider given the rugged terrain across the survey area.
The DIAS32 demonstration survey over the Rosemont deposit was successful in mapping the resistivity and chargeability characteristics along the survey line over the known mineralization. Both the resistivity and chargeability data sets clearly map the unconformity between the volcanic cover and the host limestone units. This contact varies from a depth of approximately 150 m in the western portion of the deposit to over 500 m in the eastern portion. The chargeability data set clearly identifies the known sulphide mineralization across this section and appears to map this parameter to a depth of several hundred metres, particularly in the central and eastern portions of the pit area. The chargeability also appears to map variability in the tenor of the sulphide mineralization from unit to unit within the deposit area.
The DIAS32 distributed array approach to surveying provides a higher level of confidence in the final model images because the method removes bias caused by the direction of current flow. The method provides coverage to great depth and can be used with confidence for drill targeting.
Uranium mineralization in the prolific Athabasca Basin is found at or near the unconformity between overlying sediments and the basement units, and are also found at or near fault structures that cut through the basement and into the basin sediments. EM methods are often used to detect graphite in these fault structures that may be associated with uranium mineralization. The electrical resistivity method is effective in mapping the alteration in the overlying sediments that often accompanies the mineralizing process. Current exploration in the basin ranges from surface to many hundreds of metres, and at these depths traditional methods of exploration are challenged. The electrical resistivity method can effectively search to depths of 800 m and more.
An efficient fully-distributed array survey that yields dual array data will provide for accurate 2D and 3D resistivity images of the subsurface. In many areas of the basin a 2D solution is appropriate, but in some cases, a 3D array is recommended. The resistivity images will provide an accurate and continuous image of the subsurface to allow for selection and prioritization of targets for drill testing.
Dias delivers unique geophysical solutions to geoscience challenges through the application of innovative technologies. Dias offers induced polarization and resistivity survey services using its proprietary DIAS32 system, a uniquely efficient and effective technology. Dias provides full tensor magnetic gradient survey services using the SQUID-based FTMG system in partnership with Supracon AG.
Independence Gold has plans to carry out a detailed 3D IP and MT survey on the 3Ts project using the Dias32 at the end ofRead More
High priority gold targets associated with surface gold mineralization have been identified by Pelangio Exploration Inc. following an IP/resistivity survey completed by Dias Geophysical on their Hailstone property in Saskatchewan.Read the press release
Dias Geophysical’s 3DIP survey for Gold Bull Resources Corp. resources yielded excellent results and defined promising new drill targets on the Sandman Gold project in Nevada. This was the first 3D IP/resistivity geophysical survey that Gold Bull has completed on their property and they will continue to use this type of surveying for future targeting.Read the press release
Dias Geophysical completed a DIAS32 3D resistivity and IP survey over Declan Cobalt’s Tisová project in the Czech Republic. The property hosts polymetallic VMS mineralizationRead More
Join us virtually for the PDAC premier mineral exploration and mining convention between March 8-11, 2021.
Join us virtually at AME’s first Remote Roundup conference from January 18-22, 2021.
Join us in Winnipeg on November 18 and 19 at the CCMEC conference.
Please plan to visit us at our booth at the Roundup in Vancouver from January 28 to 31.
Please join Dias Geophysical in the exhibition hall at the DMEC conference from October 22 to 25, 2017. Dias will be sharing a booth with Supracon AG for the duration of the conference. Glenn Chubak, Dias’ VP Technology, will be co-chairing the technical session on Ground and Borehole Geophysics on Tuesday morning, and Jonathan Rudd, Dias’ president, will be speaking on the Progress of the Electrical Resistivity and IP Method, also on Tuesday morning. Dias Geophysical is a proud sponsor of the event.
Dias Geophysical is exhibiting at the PDAC Conference from March 5 to 8. Please visit our booth # 6210N in the North Convention area.
Join us at the Roundup from January 23-26, 2017, at our booth #1519.
Stop by the Dias Geophysical booth at the ASEG conference in Perth, Australia.
Join Dias Geophysical at our booth at the AMEBC Roundup conference in Vancouver.
Dias presents an overview of the DIAS32 system at the KEGS monthly meeting in Toronto.
Dias presents two papers at the 3D IP and Resistivity workshop at the SEG conference in Denver.