equipment: Autograv CG-5 gravimeter by Scintrex
Gravimeter is a basis equipment to carried out to gravity surveys. It has a very high measurement accuracy, so it can be used to research of a variation of gravity method – microgravity.
1. Recreation of areas subjected human impact on the environment
As a result of mining activities, a network of excavations is created which in recent times have rarely been filled-up and pose a threat to the surface of the area. There are also changes in hydrological conditions and often there is a phenomenon of suffosion, which results in the appearance of secondary voids and unconsolidated in the rock mass. They constitute a potential threat to the terrain surface in the form of continuous deformations, but also more dangerous discontinuous deformations. Microgravity method allows for early detection of density changes in shallow parts of the rock mass, before any occurrence of symptoms of these changes on the surface of the terrain.
2. Gravity monitoring
Periodic gravity measurements carried out on permanently stabilized stations allow to track density changes occurring in the rock mass.
3. Landscape planning
The microgravity method can be used to better identify near-surface geological structure, as well as to determine geotechnical conditions in the area of planned investments. This is particularly helpful in areas where mining activities were carried out.
4. Design of roads and motorways
The microgravimetric method allows the recognition of near-surface distribution of the density of rock formations, which will enable better recognition of shallow geological structure and the detection of zones of possible loosening, dangerous for the use of roads. Knowledge in this area enables us to design ground reinforcements as well as flyover and bridges.
5. Research of the condition of mining shafts
The CG-5 gravimeter is so sensitive that it allows the location of voids and unconsolidated zones around the shaft, but also allows you to perform research inside the shaft and recognize the condition of the rock mass outside its walling.
6. Research of the condition of levee and dams
Gravimeter allows you to perform microgravity survey on levees and earth dams surrounding watercourses and water reservoirs and to detect any unconsolidated zones in them. This makes it possible to carry out safety work and to prevent levees and dams from breaking.
7. Determination of bulk density
The CG-5 gravimetric sensitivity allows to determine the average bulk density of materials stored in heaps eg coal in heat and power plants, mineral salts in chemical plants, etc.
8. Detection of voids
Detection of natural and anthropogenic voids in rock formations is widely known and used in the world. The Department of Geophysics has many years of experience in this field.
9. Detection of unconsolidated zones over anthropogenic voids
There is also the possibility of controlling the state of the rock mass over the anthropogenic voids. Knowing the geometrical parameters of the voids and the density of the surrounding rocks is the possibility of detecting the looseness in the rocks above it.
The gravity method is an auxiliary method for oil and gas exploration. It allows for better recognition of the geological setting of the examined area, especially in terms of the occurrence of porous reservoir rocks, stratigraphic traps, etc. This method is successfully used to contour deposits with different density than surrounding rocks e. g. lignite or hard coal, iron deposits etc.
- Tectonics recognition
The method allows for general recognition of tectonics of the examined area, with particular emphasis on dislocation zones.
- Geological setting recognition
Gravity and microgravity methods are also suitable for the recognition of near-surface and deeper geological structure. They do not have the same accuracy as seismic or electrical methods, but they are a very good complement to them.
- Temporal gravity changes in geodynamics research
Geophysical methods are also used to research geodynamic processes, and above all the gravity method . This method, on the basis of temporal gravity changes, allows you to track rock-movements, even though the movements are small.