For a successful completion of the survey campaign our professionals and technicians get prepared, trained and equipped with all necessary electronic instruments, ADC dataloggers and filed accessories for setting up the survey grids, testing the instrumentation and acquiring the required geophysical data. The field data acquisition follows the industry standards established for the practice of the geophysical profession at all times.
The equipment operators constantly adjust to the existing site conditions and project requirements in a safe and cautions matter while maintaining the accuracy of the measurements. Our management and professional staff encourage our field technicians and operators to adhere to the well stablished and approved mandates for all of our geoscientific projects. Common geophysical techniques used by Geophysics HM Ltd are Ground Penetrating Radar, Refraction Seismic, MASW, Induced Polarization, ERT.
Geophysics HM Ltd provide a wide variety of data acquisition for small-to-large scale geoscientific projects in Canada and internationally. The field data acquisition follows the industry standards established for the practice of the geophysical profession at all times.
Geophysical equipment are design and build for measuring the natural occurring physical fields and responses generated from the differences in the physical properties of the earth rock formations, subsurface conditions and manmade materials and phenomenon. The measured electric signal originated from the interface between two materials with different physical properties can be natural occurring, transmitted, induced, reflected and refracted. The geophysical techniques that measure the natural occurring physical fields (Magnetic, Magnetotelluric and Gravity) are named passive methods. The methodologies and instruments for measuring the subsurface responses generated or induced by man are called active techniques such electric, electromagnetic and seismic.
The equipment operators constantly adjust to the existing site conditions and project requirements in a safe and cautions matter while maintaining the accuracy of the measurements. Our management and professional staff encourage our field technicians and operators to adhere to the well stablished and approved mandates for all of our geoscientific projects.
Electronic instrumentation, accessories (spreads, sensors, sources of signal excitation) and measuring tools are designed for deployment over different ground surfaces (topographic or man-made material surfaces) and underground conditions, environments and dimensions (1D, 2D and 3D). Most of the geophysical methods are non-intrusive, fast, inexpensive, and possess a great deal of detail when compared to other conventional exploration techniques deployed in or between boreholes. Different instruments and field accessories are brought to the site for any geophysical survey, including data loggers, communication cables, multi-wire spreads, power generators, wooden and steel stakes, measuring wheels, flags, GPS systems and radio communication equipment.
At Geophysics HM Ltd the geophysical electronics and transducers are well maintained and treated with extreme care and according to manufacturer technical specifications and recommendations to avoid bad data collection, instrumentation errors, costly repairs and survey delays.The electronic instruments and sensors are the most important parts of the geophysical data acquisition systems. They are built with delicate analog to digital converters, sensing devices, electric boards and precision moving parts. The instruments are required to perform effectively over extreme weather, terrain and working conditions.
StructureScan Mini XT
The Structure Scan Mini XT is GSSI’s newest generation of our very popular all-in-one ground penetrating radar systems. The StructureScan Mini XT offers a 2.7 GHz antenna for superior target resolution and can reach depths up to 60 cm (24 in). This system is designed with the option for users to add accessories and tailor the unit to specific applications. With multiple modes of operation, the StructureScan Mini XT is ideal for locating rebar, conduits, post-tension cables, voids and real-time determination of concrete slab thickness.
Scan Pro GPR
With UtilityScan Pro, users can quickly identify and mark the position and depth of metallic and non-metallic objects; including utilities such as gas, communications and sewer lines as well as underground storage tanks and PVC pipes. Based on the SIR 4000 controller, the UtilityScan Pro provides the GPR professional with solutions to any underground locating situation .
GSSI - 200HS Antenna
GSSI GS Series, is a new generation of high-performance antennas targeting applications that require deeper penetration depths. The first antenna in the series is the 200 HS. This digital, wireless antenna features a 200 MHz center frequency and employs GSSI’s proprietary HyperStacking® technology. This technology improves signal to noise performance and increases depth penetration under all soil conditions. The GS Series is ideal for geophysical, geotechnical, and environmental applications that require high reliability under challenging survey conditions.
GSSI - 100MHz Antenna
The 100 MHz antenna is used for deep subsurface applications. The 100 MHz monostatic combines the transmit and receive electronics in a single antenna housing, while the 100 MHz bistatic antenna is a versatile antenna pair that can operate in three different configurations to optimize performance. Both antennas are compatible with the SIR 4000 and SIR 30 control units.
Road & Bridge Scaner
The RoadScan™ 30 system provides users with an effective tool for quickly determining pavement layers at high speeds. RoadScan is able to collect data densities not obtainable using other labor-intensive methods commonly used for pavement testing. BridgeScan™ is a complete, affordable GPR system that is an effective tool for quickly determining the condition of aging bridge decks, parking structures, balconies and other concrete structures. The system is also used to obtain accurate concrete cover depth on new structures.
The EM31-MK2 maps geologic variations, groundwater contaminants, or any subsurface feature associated with changes in ground conductivity. Using a patented electromagnetic inductive technique that allows measurements without electrodes or ground contact. With this inductive method, surveys can be carried out under most geologic conditions including those of high surface resistivity such as sand, gravel, and asphalt.
The EM61-MK2A is a high sensitivity, high resolution, time domain metal detector suitable for the detection of both ferrous and non-ferrous metal. Typical target response is a single, sharply defined peak, facilitating quick and accurate determination of location. Achievable depth of detection will depend on several target characteristics, with the surface area and orientation of the target of particular importance. A single 200 litre (55 gal.) drum can be detected at depths greater than three meters.
Geonics Borehole EM39
The EM39 provides measurement of the electrical conductivity of the soil water matrix surrounding a borehole or monitoring well using the inductive electromagnetic technique. The unit employs coaxial coil geometry with an intercoil spacing of 50 cm to provide a substantial radius of exploration into the formation while maintaining excellent vertical resolution. Measurement is unaffected by conductive borehole fluid or the presence of plastic casing. The instrument operates to a maximum depth of 500 metres.
The Geode Exploration Seismograph is the most popular seismograph in the world, used by both academics and geophysical professionals. The Geode is a versatile and flexible seismograph, small and lightweight enough to pack into your suitcase, yet easily expandable if needed for full-scale 2D and 3D surveys via our intelligently designed distributed architecture. Use the Geode for reflection, refraction, MASW/MAM, or tomography surveys, as well as for more niche use cases such as earthquake, quarry blasts, or heavy equipment monitoring.
ERT & IP SYSCAL Plus
The SYSCAL R1 Plus resistivity meter is specifically designed for medium-depth exploration. It combines a power source, transmitter up to a 200W or 800Vpp output voltage, and a 2 channels receiver in a single unit; its compactness makes it an effective tool for intensive resistivity surveys. The measurement is fully automatic, controlled by a microprocessor: automatic self-potential correction, automatic ranging, digital stacking for signal enhancement, error display in case of procedure troubles.
GEM’s Overhauser Magnetometer system is a revolutionary geophysical instrument developed by GEM to offer a rugged, low power, and sensitive alternative to Proton Precession and some other alkali vapour magnetometers. GEM’s GSM-19 (Overhauser) magnetometer is a primary standard in mineral exploration and magnetic observatories. As a standard for magnetic observatories, this system has proven itself – for its high sensitivity, absolute accuracy and long life. Overhauser magnetometers are also used in archaeology, pipeline mapping, UXO detection, and other geological, geotechnical and environmental applications.
GDD GRx8-32 IP Receiver
The highly sensitive GDD IP Receiver (models GRx8-32 and GRx2) is a compact unit designed for high productivity resistivity and time-domain induced polarization (IP) surveys in mineral exploration, groundwater exploration, geotechnical investigations and other related fields.
NUMIS NMRS System
The NUMIS Poly device is a Magnetic Resonance Sounding (MRS) system for the direct detection of shallow groundwater down to 150 m of depth. NUMISPoly is a modular multi channel MRS equipment designed with units weighting 25 kg or less, making it man portable. The transmitter unit produces pulses at the Larmor frequency. The receiver units (up to 4) measure the MRS signal and the noise, after filtering, amplification and analog to digital conversion. The PC computer receives raw data, then processes, displays and stores them (including time series) for further interpretation.
3D Distributed DCIP
The 3D Distributed DCIP system from IRIS Instruments France were specifically developed for precise full waveform time domain induced polarisation, Resistivity and self-potential measurements. Each system is fully independent; incorporating its own power source, GPS module and digital memory for up to 3 months continuous recording. The I-FullWaver can be used alongside the V-FullWaver or ELREC Induced polarization receivers.
Scintrex CG-5 Autograv
The CG-5 Autograv is a microgravity meter with a standard resolution of 1 microGal and a standard deviation that is < 5 microGals. It is the fastest, lightest, most cost efficient gravity meter on the market today. With minimal training a user can quickly collect and record reliable gravity data.
The vLoc3-9800 from Vivax-Metrotech is a fully-automatic gain control, precision left/right guidance utility locator. The vLoc3-9800 is built on a new Triaxial 3D antenna architecture with highly configurable features. The vLoc3-9800 offers two passive modes and all available frequencies between 16Hz up to 200kHz. Audio and mechanical vibration alerts can also be configured by users providing warnings for shallow depth, overload, overhead cables and excessive swinging. The vLoc3-9800 can be equipped with optional Bluetooth module for GPS mapping and MLA (marker locator adapter) add-on for locating buried EM markers and TX Link for communications between receiver and transmitter. A few applications ideal for low-frequency locating is long-haul fiber lines, metropolitan loop networks, and pipeline transmission lines.
At Geophysics HM Ltd the geophysical professionals and technicians routinely perform and request the manufacturer of the field survey equipment. Instrument calibration logs and time-lapse performance tests are included in the geophysical operating procedures and provided to clients upon request.
The collection of the geophysical data is carried in survey grids, profiles and stations previously established over the survey area. A variety of geophysical surveys require collecting data moving the instrument at equal intervals along straight lines above the surface (e.g. MAG, GPR). Other techniques use multi-wire lines with sensors attached at equal intervals spread in the surface along the survey path or boreholes (e.g. Seismic, ERT, Electromagnetics).
Local and geographic coordinates for the grids, profiles and stations are collected during the survey for later referencing and map creation. The grids are layout in the field using commercial measuring tapes, measuring wheels, theodolite and Global Positioning Systems.
For acquiring the geophysical data it is required to have profile lines with stations positioned over the surface with paint, flags or stakes. A survey grid is formed by a combination of base lines and profile lines arranged in parallel and perpendicular pattern if required. The geophysical grid size, the number of lines and the interval between the lines will be selected based on the expected limits of investigated target along the strike direction perpendicular to the survey profiles.
For a successful survey, a few survey lines should cover the background response beyond the target extent. The grid line interval is dictated by the geophysical methodology used. In most of the cases for achieving a good survey resolution at least 2-3 lines should crosscut over the investigated target. For a proper target extent interpretation, depth and dimension estimates the survey profiles need to be positioned perpendicular to the longest axis of the expected target.
In order to avoid aliasing during the data acquisition, the number of stations and the interval along the survey profiles should not be higher than the Nyquist sampling interval. Oversampling will not affect the quality of the data or the results of the investigation, although it is not recommended and should be avoided to reduce the cost of the acquisition.
In general, the geophysical reconnaissance surveys are intended to cover large areas very quickly, largely reducing the initial cost of the investigation. These surveys will produce a general picture of the underlying soil types, geological structures, fill and waste materials, environmental conditions and mineral assemblies.
The detailed geophysical surveys are oriented for investigating relatively moderate to small areas where small variations of the investigated physical properties are critical for successfully completing geological , geotechnical, environmental, archeological, mining and construction projects among other applications.
At Geophysics HM Ltd the quality of the geophysical data is the heart of our investigations. The control is done on all stages of the project execution, starting from the survey planning, data collection, processing, inversions and interpretation. Data quality is a top priority from the survey beginning until the end when thereport is completed.
Data is constantly monitored as a survey progresses to ensure that equipment is functional, the correct equipment and parameters are being used, and that the data is of sufficient quality to ensure meaningful processing and interpretation. Based on these preliminary observations, modifications can be made to the survey plan if the client wishes to focus on particular features that become apparent as data is collected. Quality assurance takes place before a survey begins. The geological and geophysical responses are considered and modelled prior to surveying if required. Based on the objective of the survey, the correct equipment and geophysical method will be selected to ensure optimal results are obtained.
At the end of each working day the acquired geophysical data is dumped to a field processing computer and reviewed for quality assessment. If the data is not of adequate quality for data inversion and interpretation a reacquisition or modification of the survey methodology is recommended.
Site documentation is done by the means of written notes, audio and video records, photographs or sketching. Photographs showing the geophysical instrument layout and site conditions at the time of the survey should be included in the digital archive. Annotations of the geophysical parameters and site conditions should be available in the filed notes supplied along with the geophysical report. Documents and sketches illustrating the terrain conditions, weather, obstructions, survey grid layout, reference positioning, sources of noise and machinery within the survey area at the time of the survey should be provided