1. INTRODUCTION

With governments and industry wanting to develop clean hydrogen, there is an opportunity to initiate exploration projects for hydrogen (and also helium) from natural sources in regions like Témiscamingue (Quebec). The search for hydrogen (H2) and helium (He) sources is relatively new, which explains the lack of geoscientific information available on government web sites such as SIGEOM (MRN). However, large corporations, such as Total (France), finance vast exploration projects (e.g. in the Pyrenees) for the search for natural hydrogen (Dugamin et al., 2019). The prospecting methods (geochemistry, geophysics) used for hydrogen exploration are similar to those used in geothermal energy and for natural gas exploration (Tian et al., 2022). For companies like Quebec Innovative Materials Corporation (QIMC), there would be real opportunities in this area, because during exploration work for natural hydrogen (or native hydrogen), it is also likely to find helium and also geothermal heat sources. Economic projections show that global hydrogen consumption is expected to increase in the coming years (Fig. 1). This is an opportunity for QIMC to position itself relatively early in the process of exploration and possibly production of hydrogen and/or helium in Quebec.

The principle of He-H2 exploration is, as for natural gas, to find reservoirs rich in hydrogen or helium and to exploit them commercially from the surface (wells) (Milkov, 2022). Hydrogen and helium being gases often associated in nature, it is also possible to exploit helium which is a rare industrial gas.

Figure 1. World evolution of hydrogen consumption for the period 2013-2030. Source: http://newenergynews.blogspot.com/2013/11/world-still-building-hydrogen-hiway.html.

2. LOCATION OF EXPLORATION WORKS FOR HYDROGEN AND HELIUM

Given the lack of geoscientific data on hydrogen and helium from natural sources in Quebec and also for most of the Canadian territory, QIMC proceeded to a judicious selection of exploration permits based on current global knowledge on the geology of hydrogen and helium showings in the world. First, regions combining Precambrian bedrock rich in potassic rocks (radiogenic) and Paleozoic sedimentary rocks were prioritized. This type of geological environment is known to be able to form H2 and He. In addition to these lithological features, QIMC searched for regions affected by rift and graben tectonic systems. The latter are particularly well developed in eastern Quebec. The Ottawa-Bellechere and Lake Témiscamingue grabens (Fig. 2 and 3) are tectonically active structures as evidenced by the presence of continental intraplate seismicity well documented by the Geological Survey of Canada.

Extensional geological structures, such as the Temiscamingue graben system (Fig. 2 and 3), are known to contain normal faults that can focus gas circulation to the surface. The presence of a cover of Proterozoic (Cobalt Group) and Paleozoic (New Liskard) Ordovician sedimentary rocks is important in order to provide potential storage sites (reservoirs) and impermeable covers limiting the dispersion of gases towards the surface. The presence of serpentinized ultramafic rocks (altered komatiites and dunites) and Archean iron formations (Baby Group) beneath the sequence of sedimentary rocks is a potential favourable source for hydrogen production. The presence of a thick sequence of arkosic rocks in the Cobalt Group and of Precambrian potassic granitoids in the Lake Témiscamingue area are potential sources of helium production (sources rich in U and Th).

Figure 4 shows the spatial distribution of QIMC exploration permits in the municipality of St-Bruno-de-Guigues (MRC du Témiscamingue).

Figure 2. Tectonic zones of the Ottawa-Bonnechere and Timmiskaming (or Témiscamingue in French) grabens (Quebec and Ontario). The QIMC exploration area is located in the Timmiskaming graben zone.

Figure 3. Map of the Timiskaming graben located on the border of Quebec (east) and Ontario (west). Some faults on the Ontario side of Lake Timiskaming are shown and correspond to topographic escarpments.

Figure 4. Map of QMIC exploration permits located in the area of the municipality of Saint-Bruno-de-Guigues (MRC du Témiscamingue). Modified from the MRN website (SIGEOM). Note that the Stuart Deveau claim area was re-staked by QIMC on May 6, 2023.

3. GEOLOGICAL CONTEXTS FAVOURABLE TO THE PRESENCE OF HYDROGEN AND HELIUM

3.1 GEOLOGICAL AND GEOCHEMICAL PROCESSES INVOLVED IN THE FORMATION OF HELIUM

Helium-rich fields can be subdivided into three categories. Those rich in methane, associated with natural gas deposits, those associated with nitrogen (N2) and those associated with CO2 (Liu et al., 2023). The close association of He-CO2 and He-N2 explains the importance of measuring CO2 and N2 during prospecting work for helium. Instrumentally, it is very easy to measure CO2 and N2 concentrations directly in the field, while helium measurement is more complex and requires, in many cases, the use of a specific mass spectrometer. Unlike methane, helium-rich reservoirs can be considered economical from low concentrations such as 0.3% (3000 ppm). Deposits associated with N2 have recently been discovered in the Colorado plateau (USA) and in the Tancheng- Lujiang fault zone in China. Those rich in CO2 has been discovered, among other places, in the Colorado Plateau and in the Western Cordillera (Halford et al., 2022). It is noteworthy that the helium deposits in production are mainly present in Paleozoic rocks. However, several deposits are also present in Proterozoic rocks. In contrast, there is no helium deposit in production in Archean rocks. The global compilation by Liu et al. (2023) shows that reservoirs can be located at depths of 0 to 3 km with a majority of reservoirs located at depths between 1 and 2 km. Note that deposits located between 0 and 1 km are almost as common as those located between 2 and 3 km deep. In the context of exploration in the Témiscamingue area, the abundance of Proterozoic sedimentary rocks (Cobalt Group) and the presence of Ordovician limestone and detrital rocks (quartzite and sandstone) near Lake Timiskaming constitute relevant exploration targets for helium exploration.

The local geological context is a key factor in an exploration strategy for H2 and He. In addition to considerations of reservoirs (porous rocks) and impermeable barriers (e.g. shales), rocks likely to produce the desired gases must be found in the region. For helium, this gas can come in small proportion of mantle sources ( 3He). The latter is often observed in active volcanic terrain. This primitive (or primordial) gas is added to 4He (distinctly dominant) which comes from crustal sources via the alpha decay of the natural occurring of radiogenic isotopes of uranium (235U and 238U) and thorium (232Th) (Fig. 5).

Figure 5. Alpha decay of a uranium-238 nucleus and production of radiogenic helium.

Unlike hydrogen, helium is an inert gas and therefore non-reactive. Its solubility in water is relatively low and this gas migrates easily to the surface or to reservoirs that can accumulate it over long periods of time. Unlike hydrocarbons, when present in the area, helium continues to form due to the very long half-lives of uranium and thorium isotopes. Rocks rich in U and Th are mainly felsic and potassic in nature, such as Precambrian felsic granites and gneissic rocks. These rocks are particularly abundant in the Canadian Shield in Quebec and Ontario (e.g. Témiscamingue, Lac St-Jean and Charlevoix). In addition, certain sedimentary rocks such as arkose are also recognized as potential sources of helium production. These rocks are very abundant in the succession of Proterozoic Huronian sedimentary rocks of the Lake Témiscamingue region.

In continental environments, many of the largest helium accumulations are observed in cratonic terrains such as the Canadian Shield. These vast Precambrian terrains are tectonically stable environments over very long periods of time. Late extensional environments such as rifts and grabens (e.g., Timiskaming and Saguenay graben) can facilitate gas migration to shallow reservoirs or the surface, via vast networks of faults (Fig. 6).

Figure 6. Simplified geological section of the geological structures and formations associated with the Saguenay Graben.

3.2 GEOLOGICAL AND GEOCHEMICAL PROCESSES INVOLVED IN THE FORMATION OF HYDROGEN

The observation of hydrogen leaks in the ground is a phenomenon frequently observed on the surface of the Earth. The phenomenon is observed in rocks from different geological periods and in a multitude of geological environments. The work carried out on the edge of the Pyrenees Mountains belt (France) is a good example showing the presence of significant regional hydrogen anomalies observed in the soils of the Pau region (Fig. 7).

Figure 7. Map showing the spatial distribution of hydrogen anomalies measured in the soils of the Pau region (Pyrenees, France). Note the spatial association with regional faulting and hydrogen concentrations. Map taken from Lefeuvre et al. (2021).

Unlike helium, this observation highlights that a multitude of geochemical processes can form hydrogen. The article by Milkov (2022) lists some thirty physical and chemical mechanisms that can lead to the production of natural hydrogen. The main mechanisms that can lead to the production of hydrogen can be grouped into abiotic or biotic processes. The abiotic processes include: 1) degassing of primordial hydrogen from ultra-deep sources in the Earth's mantle, 2) radiolysis of water by radioactive elements (U, Th, K) present in the Earth's crust and 3) interactions between water and rock minerals (mostly iron-rich minerals). Biotic processes involve the degradation of organic matter in rocks (source of hydrocarbons) as thermal maturity increases (Mahlstedt et al., 2022) and also bacterial processes that can produce hydrogen (e.g., anoxic peatlands).

In geologic materials, oxidation of iron-rich rock minerals (Fe2+) such as iron formations (magnetite-rich facies) and ultramafic rocks (e.g., peridotites and ophiolites) can generate hydrogen (Tian et al., 2022). This is particularly well demonstrated in Turkey by the Chimaera gas seepage, which emits natural hydrogen and has fuelled “eternal” flames for thousands of years (Etiope, 2022). Despite the fact that the majority of hydrogen observed at the surface comes mainly from chemical reactions involving fluids and minerals, certain accumulations of hydrogen come from the radiolysis of water or hydrocarbons (ex. CH4) by natural radioactive elements present in certain geological formations. Potassic granite, arenite (e.g., potassic sandstone from the Cobalt Gp in Témiscamingue) and evaporite (e.g., Iles-de-la-Madeleine) are crustal rocks capable of producing hydrogen by radiolysis.

4. METHODOLOGY

INRS conceptual exploration approach is based on a multidisciplinary study involving, among other things, the geochemistry of gases in the vadose zone of soil (soil not saturated with water), the chemistry of atmospheric gases measured at very low elevations above the ground, geophysics (gravity, audiomagnetotellurics), structural geology and drone imagery (Lidar, SFM, multispectral).

In order to maximize the probability of discovering hydrogen and helium leaks, it is necessary to locate faults and other geological discontinuities. In Quebec, these structures are most often masked by Quaternary glacial deposits and lake sediments. Being difficult to observe, these structures are most often regionally extrapolated or inferred from fragmented geological data or from imprecise indirect methods (e.g., Quebec Government low-resolution magnetic map). On the other hand, CO2, CH4, radon (and thoron), He, H2 are gases frequently used to highlight the presence of faults masked by overburden (e.g., Toutain and Baubron, 1999). Similarly, mobile gamma radiometric measurements (on the ground) can be used to locate uranium enrichment halos often testifying to the presence of degassing faults. These halos form by precipitation of uranium from groundwater when the gas concentration becomes high, favouring the formation of reducing media.

Lidar (airborne laser) is useful for locating local linear topographic breaks indicating the presence of recent (neotectonics) or old faults. Finally, geophysical methods with high vertical penetration such as audiomagnetotellurics (AMT) can locate and assess the importance of structures observed on the surface (vertical penetration of 0-2000m). Typically, for gases like helium, the greatest outgassing comes from deep-rooted faults in the continental crust.

4.1 GEOCHEMISTRY AND DYNAMICS OF SUBSURFACE GAS SEEPAGES

At the Earth's surface, gases are transferred to the atmosphere via diffusive (slow) processes and locally by advective (fast) processes (Fig. 8). For regional exploration, anomalous areas are most often identified by preliminary Soil-Gas surveys that are sensitive for locating diffuse sources. Subsequently, anomalous zones in H2 or He are subject to high-resolution gas measurements to assess the gas fluxes from advective sources. These sources bring large volumes of gas to the surface (degassing zone).

At the regional scale, it is possible to measure gas concentrations present in the vadose zone in order to locate anomalous areas potentially favourable to the presence of gases such as helium and hydrogen. This is demonstrated, among other things, by the study of helium distribution on the volcanic island of Santorini in Greece (Fig. 9).

Figure 8. Advective and diffusive fluxes of radon (Rn), CO2, H2 and Hg in the vicinity of a fault zone cutting granitic rocks.

Figure 9. Helium and CO2 concentrations in soils from the island of Santorini (Greece). Source: Tarchini et al. (2019). The Soil-Gas method is effective in locating areas of interest (diffuse sources) for the exploration of gases such as helium.

4.1.1. Significance of regional faults

The Temiscamingue graben area is severely affected by seismicity and normal faulting related to extensional processes still active today (Fig. 10). Such structures may be important in allowing the transfer of gases from deep sources to shallow environments. For H2 and He exploration, these faults must be well located in space (Lidar, AMT, gravity, magnetometric surveys) and geophysical surveys must be carried out in order to verify the vertical extension (in depth) of the faults. The deeper these structures are, the greater the potential for gas transfer

Figure 10. Schematic block diagram showing normal faulting (collapse) associated with the Témiskaming graben.

Due to high porosity and permeability, fault zones promote gas focusing and advection within a relatively restricted area of fractured rocks (Fig. 8). The advection of gases, in such an environment, results in a significant transfer of gases towards the surface (flux). To detect areas of potential gas advection, it is necessary to measure gas flows in the field (concentrations per unit area / time) with devices specially designed for this purpose. As mentioned in this document, fundamental structures such as faults (and shear zones) are more permeable to gas than intact rock. In many cases, this allows the formation of detectable gas leaks. In the presence of a porous structure in the rock (e.g. Témiscamingue lake dolomitized Ordovician limestone) and an impermeable cover above (e.g., shale, basalt, marine or glaciolacustrine clays), these gases can form potentially exploitable accumulations (Fig. 11).

Figure 11. Conceptual vertical section showing the accumulation of helium in a porous geological structure surmounted by the presence of a barrier of impermeable rocks (shale).

Sometimes, on the surface, these gas leaks can form sub-circular structures with little vegetation (detectable by Lidar) but most of the time these leaks are cryptic and require soli-gas analysis in order to be able to locate them in the field. The use of multi-spectral cameras on drones is an often effective indirect method for locating degassing areas in forest environments. The method detects stresses in tree vegetation related to the depletion of oxygen in the soil and changes in pH (acidity) and redox potential related to the presence of gas leaks. For example, the use of the Agrowing multispectral lens interface with the ADTI 61 Mpixel camera makes it possible to cover large areas in wooded areas.

4.1.2. Chemical analysis of gases

The evaluation of the gas transfer mode requires the use of optimized methods to measure the diffusive or advective fluxes. For H2 and He exploration, two gas analysis methods should be used. The first is a Soil-Gas prospecting method which consists of analyzing gases present in the soil and more precisely at a depth of 1m (detection of diffusive anomalies) and the other is a method for measuring gases flux present immediately above the soil-atmosphere interface (detection of advective flows).

4.1.2.1 Gas analysis at the soil-air interface and advective flux measurements.

This method is based on the measurement of gases present immediately above the soil-atmosphere interface. Measurement in contact with the ground makes it possible to minimize the dilution by atmospheric gases. The technology that could be used in the second year of the project for this analytical procedure is based on laser optical cavity spectroscopy allowing the simultaneous measurement of CO₂, CH₄ (Li-Cor-7810). To locate areas of gas advection in the field, it is necessary to use ultra-sensitive systems (ppb detection limits) capable of measuring gas concentrations continuously over variable periods of time. Helium and hydrogen field analyzers are not designed for such continuous operation. On the other hand, carrier gases such as CO₂ and CH₄ should be measured in the field because they are often associated with hydrogen and helium seepages.

Since CO₂, CH₄ and Hg are very sensitive for locating geological fault it could be possible to carry out a very large number of measurements in a working day (high productivity) using Li-Cor and Lumex instruments. Note that the Li-Cor gas detector is specifically designed to assess advective fluxes. It makes it possible to assess the importance of gas leaks in sectors deemed to be anomalous in He and H₂.

Figure 12. Portable 7810 Li-Cor detector coupled to a gas flow chamber.

Figure 13. Lumex gaseous mercury detector. Field measurements in British Columbia (Rukhlov et al., 2021).

4.1.2.2 Soil-Gas geochemistry in the soil (vadose zone)

Soil-Gas geochemistry is based on the sampling of gas present in the water[1]unsaturated zone of the soil (vadose zone). Using a probe specially designed for gas sampling in soils, gas samples are taken at a depth of about 1m in the ground. Such gas sampling is possible in relatively dry weather conditions (summer). Since H₂ is more concentrated in nature than helium, its detection can be done more quickly in the field using portable gas detectors (e.g., H₂ specific electrochemical detector). Since helium cannot be easily measured in real time, its precise analysis (with less than 1 ppm precision) must be deferred over time and requires spectrometric analysis in the laboratory. However, helium analyses, with a limit of 2 ppm, can be carried out in the field using the Agilent PHD 4 technology. PHD 4 analyzes are useful for locating advective leaks and anomalous regional areas but for diluted diffusive gas concentrations (near background level), the detection limit maybe too high. However, conclusive regional studies have been successfully carried out with this method, which could be advantageously used in the Témiscamingue area, especially in the second phase of the soil-gas surveys and more specifically to densify the data in the vicinity of anomalous sectors in He detected during the first phase of soil-gas survey.

In the field, other gases such as H₂S, SO₂, CS₂, O₂, and possibly radon should be analyzed in order to optimize the process of detecting sites favourable to the presence of helium and hydrogen (Fig. 14). The analysis of these gases also makes it possible to specify the characteristics of the source regions from which the gases come. Since these gases are measured with the same detector as for hydrogen, the analysis of H₂S, SO₂, CS₂, O₂, does not increase the analytical costs.

Figure 14. Gas anomaly related to the presence of a fault.

Soil-Gas sampling procedures is a relatively well-mastered technique in environment, soil sciences and natural resources exploration for the search for hydrocarbons, helium, hydrogen and sulphide mineralisations (Fig. 15 and 16).

Figure 15. Photographs showing different gas sampling procedures in soils.

Figure 16. Real-time gas sampling device in the vadose zone of a soil (Soil-Gas method).

To ensure quality control over the soil gas sampling process, it is important to accurately monitor the local meteorology, paying particular attention to monitoring precipitation and soil moisture. Thus, an autonomous weather station should be installed within the perimeter of the Soil-Gas surveys in the Témiscamingue area.

4.2. FIELD GEOPHYSICS

As for natural gas exploration, it is imperative to carry out geophysical surveys in order to validate the interpretations of gas geochemical surveys. Geophysical data are very important as they enable faults and lithological contacts to be located with precision. In addition, these data and inversion models make it possible to verify the vertical penetration of the faults and to visualize the presence of anticlinal folded structures, which are favourable to the storage of gases.

4.2.1 Compilation of geological and geophysical data

For QIMC exploration projects in Témiscamingue, a compilation of the geological and geophysical data available on the SIGEOM site of the MRNQ should be carried out. This data should be compiled on GIS so that it can be easily used for planning fieldwork and interpreting gas geochemistry.

4.2.2 Ground-based gamma radiometric surveys

In the subsurface, areas of high gas concentrations are often associated with oxygen-deficient environments and therefore with reducing redox potential of soils. These conditions allow the precipitation of natural uranium because this element is mobile in the context of oxygenated water and precipitates in a reducing medium. Over time, groundwater passing near the gas vent will precipitate uranium creating an anomaly characterized by uranium enrichment. Uranium enrichments near faults have often been reported in the scientific literature and during soil-gas surveys for natural gas exploration. These halos can be detected by ground-based mobile gamma spectrometers using ATVs or trucks. The latter are coupled with GPS in order to be able to map the terrain in real time (IAEA, 2003). For example, the gamma detectors used by INRS (RS[1]700 system) for ground surveys are similar to those used in helicopter-borne surveys (Radiation Solutions). Thus in real time, soils rich in U, K or Th can be detected and interpreted for prospecting hydrogen and helium and also to locate the different geological units such as between limestone, quartzite and arkose which are present in the Temiscamingue area.

For the radiometric surveys, we suggest using two gamma detectors coupled to a spectrometer and a Trimble DGPS allowing acquisition in continuous mode (one K-eU-eTh determination per second). Devices such as the RS-700 system of Radiation Solutions Inc. (Mississauga, Ontario) is very efficient for such purpose (Fig. 17).

The INRS RS-700 system comprises the following components:

 - Two 4 litres-256 cubic inches RSX-1 gamma detectors (NaI

 - sodium iodide crystal)

 - Trimble integrated GPS system

 - RS 701 spectrometer with a spectral resolution of 1024 channels

 - Panasonic Toughbook laptop

 - Mule Kawaski Diesel ATV

Figure 17. RS-700 mobile gamma spectrometric system (Radiation Solutions inc).

4.2.3 Audiomagnetotelluric survey (AMT)

The search for faults or geological contexts favourable to the presence of gas (e.g., reservoir rocks with impermeable sedimentary or volcanic cover) requires the use of geophysical imaging technologies with high vertical penetration. Frequency-based electromagnetic methods using natural sources such as the AMT method and seismic methods are particularly effective for probing the ground in depth. For the Temiscamingue project, we suggest using the AMT method because of its low cost of use, the safety during field operations (no explosives, no generators with strong electric currents on the ground). This method was successfully used for Falco Resources in the western part of the Noranda mining camp (Richer-LaFlèche et Pilote, 2018; FRQNT-MRN-Mines research grant). The INRS team successfully detected new faults along an 8,5 km long section of the Archean Blake River Group (Fig. 18). This demonstrates the performance of the AMT detection and imaging method.

Figure 18. Example of the AMT survey (INRS) of the Lac Flavrian road (Rouyn-Noranda) carried out under the FRQNT-MERN-Mines grant in collaboration with Falco Mining Resources. Note the location of the reverse fault (gold sector). Source: Richer-LaFlèche and Pilote (2018).

4.2.4 Gravity survey

The gravimetric method is very useful in gas exploration in order to delimit the presence of thick accumulations of sedimentary rocks. At the regional scale, the gravity troughs correspond to sedimentary accumulations (low density rocks) and the gravity highs often correspond to the rise of the Precambrian basement (dense rocks). For the search of H2 and He reservoirs in Témiscamingue, this method could be very useful for locating the maximum thicknesses of the sedimentary rocks of the Cobalt Group and those of the Ordovician rocks. Additionally, gravity data can be inverted in 2D and 3D to produce realistic geological models. Furthermore, gravimetry is highly sensitive to faults juxtaposing rocks of different natures. In addition, the worming modeling method, which calculates the position of faults and their geometry (dip and depth), is very effective when the spatial density of gravimetric measurements is sufficient in a region. Figure 19 shows the relationship between gravity troughs and natural gas accumulation in soils resting on the Devonian rocks of Témiscouata Formation (Appalachians of Quebec).

For gravimetric measurements, a CG5 gravimeter (Scintrex, Ontario) could be used to measure ground data. An RTK GPS system will then be used to determine the position and especially the elevation of the gravity stations with a vertical precision of less than 5 cm.

Figure 19. Gravity trough, thickening of a sedimentary basin and gas accumulation in the St-Eusèbe sector (Témiscouata): Source: Richer-LaFlèche (2008; 2011). Note that ethane is used, instead of methane, because it is only produce from thermogenic process.

4.3 LIDAR IMAGERY AND HIGH SPATIAL RESOLUTION TOPOGRAPHY

For the search for hydrogen and helium, as for natural gas, the detection of faults or other structural discontinuities (e.g., joint, diaclase) is important in order to locate potential sites of advection of gas (seepage). In a tectonically active region, such as the Timiskaming rift and graben system, recently reactivated faults can emit appreciable amounts of gas. The location of these faults is complicated by the presence of quaternary deposits (tills), of forest, agricultural and forest soils masking the bedrock and therefore the faults intersecting the rock. In such a context, drone Lidar surveys provide precise data of the surface elevation of soils and rocky outcrops with an accuracy of the order of a few centimeters and a point density of the order of 50 to 100 points of measure per m 2 . The Lidar imagery, presented in Figure 20, shows examples of Lidar data (low resolution) for the Pontiac (Kipawa and Angliers areas) and Charlevoix sectors (Malbaie area). The St-Bruno-de Guigues sector could be the subject of a high spatial resolution Lidar drone survey. However, given the presence of a forest that is often rich in deciduous trees, it would be preferable to carry out the survey after the snow melts and before the leaves come out (year 2 exploration program).

Figure 20. Lidar imagery of the Kipawa and Angliers sectors (Pontiac) and northern Malbaie (Charlevoix): Source: Forêt Québec.

Figure 21. Fault detection by SAR satellite imagery and drone Lidar.

5. DESCRIPTION OF WORK TO BE PERFORMED FOR H₂ AND He EXPLORATION IN THE ST-BRUNO-DE-GUIGUES AREA (TÉMISCAMINGUE PROJECT)

The exploration work schedule, suggested for the Témiscamingue property, is presented briefly in the form of a Gantt chart on figure 22.

Figure 22. Suggested planning for exploration work for hydrogen and helium on QIMC's Témiscamingue property.

5.1 GRAVITY SURVEY (survey time: 20 days or 771 stations)

The CG5 gravimetric survey (Fig. 23) should be done along the main secondary roads and access trails of the study area (Fig. 24). The spacing of the stations, along the roads and trails, should be around 100 m. The stations should be surveyed with a GPS RTK system with accuracy at the centimetre level. About 771 gravity stations could be measured in the St-Bruno-de-Guigues area. The gravimetric station of the Notre-Dame-du-Nord church should be used in order to establish a new reference station (QIMC station) in the municipality of St-Bruno[1]de-Guigues.

Figure 23. a) Scintex CG-5 gravimeter and b) RTK base station with Pacific Crest radio.

Figure 24. Proposed gravimetric survey lines in the St-Bruno-de Guigues area (QIMC’s Témiscamingue project).

5.2 SOIL-GAS SURVEYS

Soil-gas sampling (Fig. 25) will be carried out along many sections of the Témiscamingue property (Fig. 26). For this project, two sampling phases will be necessary. The first (phase 1) consists of a regional survey requiring very high precision measures (mass spectrometry) in order to be able to detect domains with diffusive anomalies of helium. The soil-gas samples will have to be shipped to the Geofrontiers laboratory (Texas) for the measurements of helium with analytical precision under the ppm level. Subsequently, when the anomaly sectors will be detected, high spatial resolution sampling (with spacing of 25 m) will be carried out with the PHD-4 portable helium detector (in situ measurements) (phase 2). Although the PHD-4 detector has a detection limit of 2 ppm, it was frequently used to specify the location of economically significant seepage of helium.

5.2.1 Soil-gas surveys

An average inter-sample distance of 100 m will be used as a linear sampling for the phase 1 surveys. In some cases, the spacing will be greater due to the presence of obstacles preventing sampling (e.g., watercourses, flood zone, residential sector). In this project, we have chosen the method of analyzing the free gas fraction present in the vadose zone (not saturated with water) of the soil to assess the helium potential of the Témiscamingue property.

Phase 1 high precision helium sampling (N= 250 samples): The gas samples for helium will be taken using steel probes from Geofrontiers (USA) specifically designed for the sampling of soil-gas. The probe will be implemented about 1m in the ground using a vertical axis striker fixed at the top of the probe. Following the insertion of the probe at the desired depth, a syringe will be inserted into an airtight septum located in the upper part of the probe. A first volume of gas equivalent to that of the internal tube of the probe will be taken and then eliminated in order to purge the probe from all traces of previous samples or atmospheric air accumulated during the transport of the probe. Once this step is completed, the operator will take a second sample of 20 cc and insert the latter in a gas chromatography bottle for analysis (Fig. 26). Laboratory trials have shown that gas bottles retained the prescribed vacuum and helium for a period of more than a month.

Phase 2 normal Helium survey (N= 250 samples): Following the obtaining of the analytical results from Geofrontiers (USA) and the implementation of the data on GIS, we will target the anomalous sectors to be sampled in high resolution mode. For this task, we will use the PHD-4 detector which can directly measure Helium concentrations in the field. 25 m measurements and if necessary 10 m measurements will be taken in order to locate the helium leaks responsible for the formation of the diffuse anomalies detected in phase 1 of the helium survey.

Sampling of hydrogen and other gases (N= 517 samples): Sampling specific to hydrogen and to other gases (CO2, SO2, H2S, N2, etc.), with measurements directly in the field, will be carried out during the first year of the exploration program. The sampling method resembles that for helium (soil-gas). However, the sampling procedure (pre-drilling, use of a conical auger) and the in situ gas analysis are significantly different. The number and position of field measurement stations will be similar to the helium survey.

Figure 25. Photographs showing different stages of the helium sampling process using the soil-gas method.

Figure 26. Soil-gas survey for helium (red lines) in the Témiscamingue QIMC property area (St-Bruno-de-Guigues).

5.3. GAMMA RADIOMETRIC SURVEY (7 DAYS SURVEY)

Mobile ground-based gamma spectrometry should be used because of its ability to cover, with a high density of points, significant linear distance. K%, eU ppm and eTh ppm concentrations could be acquired at a rate of one series of measurements per second. This data could be coupled in real time to a Trimble GPS. The acquisition could be carried out using a Kawasaki Diesel mule or other type of ATV. As mentioned in the text, the data could be used to 1) locate reducing halos associated with the presence of gas leaks in the soil and 2) improve local geological mapping by identifying units rich (e.g., shales) or poor in K and Th (e.g., limestone). As part of this project, the gamma radiometric system could be used for a period of 7 days.

5.4 AUDIOMAGNETOTELLURIC SURVEY (8 DAYS SURVEY)

The audiomagnetotellurics (AMT) survey is essential to: 1) understand the deep geology of the Temiscamingue graben, 2) to locate the regional faults, 3) to evaluate the importance of the faults (e.g., vertical penetration in the crust) and 4) to study the relationship between the position of the faults and that of the soil[1]gas anomalies. The AMT survey should be carried out in scalar mode and in continuous profiling with measuring stations at a 50 m spacing. Such high resolution way of measuring AMT data makes it possible to produce continuous geoelectrical imagery. The latter is essential in order to locate faults which are generally very narrow structures.

A Zonge GDP32-24bits receiver can be used with an ANT/4 magnetic antenna (Fig. 27) to do the AMT measurements in the field. For carrying out the AMT survey we suggest the following procedure:

The AMT setup will include two lines of 200 m (with 8 Ex), arranged on either side of the GDP32/II receiver. Four groups of electrodes distributed at regular intervals of 50 m will be linked together by each telluric line. The measurements will be performed in series using 8 groups of electrodes installed at a time and the magnetic receiver (Hy) will be located in the middle of the acquisition line (Fig. 28). The magnetic receiver will be oriented perpendicular to the survey line. Each sequence of measurements, or sampling stations, will thus be spread over 400 m in length. The positions of each electrode (and the receiver of each measuring station) will be located using a GPS device. Non-polarizable ceramic electrodes (with copper sulphates) will be used to accurately measure the electric field (Ex). Remember that the AMT method is based on the measurement of impedance (Z), i.e. the electric field/magnetic field ratio (or Z = E/H). Electric field values are obtained by measuring the potential difference between the ends of electrodes driven into the ground and dividing this value by the length of the dipole. The magnetic field is measured using a magnetic receiver, or antenna, made of a coil of mu-metal wire.

Figure 27. Zonge audiomagnetotelluric system with GDP32-24 bits receiver, porous ceramic electrodes and ANT/4 magnetic sensors.

Figure 28. Scalar audiomagnetotellurics (AMT) setup with 8 Ex stations at 50 m spacing that will be used for surveys in the Témiscamingue area.

5.5 LIDAR AND PHOTOGRAMMETRIC DRONE SURVEY (5 DAYS SURVEY)

This survey will be very useful to document the presence of faults or sub-circular depressions on the ground. However, the Lidar survey should be done in late fall (after leaf fall and before snowfall) or in early spring (after snowmelt). Given the immensity of the St-Bruno-de-Guigues property and Transport Canada's flight limitations of 500m (visual flight), the surveys will be carried out by carrying out measurements in corridors centred on the soil-gas survey lines. The measurements will therefore be carried out 250m on either side of the soil-gas survey lines. The airport area will not be able to be measured due to Transport Canada's drone flight bans. A Viewprotech M115 drone and an AlphaAir 450 Lidar will be used for the Lidar surveys.

5.6 MOBILE LASER DETECTOR GAS SURVEY (10 DAYS)

In the framework of this project, we will use a mobile platform coupled with a precision GPS in order to be able to detect areas of degassing of the rock and soil with gas measurements of the order of a second. This technique will use gases such as CO₂ and/or CH₄ because these molecules are very sensitive to detectors based on the use of lasers.

The objective of these surveys is to measure, using an ATV, a large number of forest or agricultural roads and trails in order to detect advective (higher flow) gas leaks. These leaks, which are often less than 10m in size (at the surface), are often associated with porous geological faults that promote the circulation of high-flow gases. Once detected, these areas will be prioritized and will be subject to a large number of Soil-Gas measurements (vadose zone) in order to check for the presence of H2 and He. The second objective of these mobile surveys is not to miss an advective area during the normal soil-gas survey because sampling interval is in the range of 100m during a regional survey.

A high-performance technology to relay this task is that of the Canadian company Boreal Laser. The latter is shown in figure 29.

Figure 29. CO₂ or CH₄ detection system based on the use of a laser source. Images taken from the Boreal website.

6. SUMMARY OF COSTS RELATED TO EXPLORATION WORK ON THE TEMISCAMINGUE PROJECT