GDD geophysical instruments for IP mining surveys
In the mining industry, IP stands for Induced Polarization and refers to a geophysical imaging technology. Induced Polarization instruments are used to measure the electrical chargeability of the subsurface during mining surveys. In order to read and analyse an IP survey accurately, a good knowledge of the local geology and mineral composition of the area is required. In this article, we’re going to take a brief look at how IP technology works and some of the different types of surveys that can be produced with the latest IP survey equipment.
How Induced Polarization Instruments Work
As mentioned above, IP instruments are able to measure the chargeability of the subsurface in specific areas, i.e. prospective mining sites. It is not the chargeability of a subsurface that really interests exploration companies of course; rather, it is the minerals and fluids that are influencing the chargeability that they are interested in.
The presence of minerals and fluids in a subsurface will lead to ionic charges, as atoms gain or lose electrons. It is these charges that begin to move when an electrical field is created in the area, by IP survey equipment. Two natural phenomena – membrane polarization and electrode polarization – reveal insights about the chargeability of rocks that can be used to determine the possible presence of certain minerals and fluids. Both these phenomena result in the accumulation of positive and negative charges, on opposite sides of pores in the rocks.
The formation of positive and negative ionic charges on opposite sides of pores is the polarization referred to in the name Induced Polarization. These formations are induced by the presence of an electrical field during the survey. With a careful reading, it is possible for experts to assess the potential of a prospective mining site from an IP survey. However, the data from such surveys is almost always used in conjunction with other geophysical survey data, to paint a fuller and more accurate picture of the site in question.
Different Types of IP Surveys
There are three main types of IP survey in use today, which we take a brief look at below. If you are planning to purchase new GDD geophysical instruments for IP mining surveys, the type of surveys you wish to conduct may affect your choice of instruments.
- 2D Surface Surveys – These are very common but conventional 2D surveys have a depth limitation that makes them less useful in certain circumstances. For depths greater than 250 metres, there is a deep 2D survey type that is suitable for depths of up to 600 metres.
- 3D Surface Surveys – Providing a high-resolution, 3D image of the area in question, 3D IP surface surveys are useful at sites with complex structural formations or where the geology is relatively unknown.
- Borehole Surveys – When conducted in a borehole, an IP survey can reveal useful information about the signature of the mineralization and the host rock.
In addition to providing valuable insights into local mineral deposits, you can also use an IP imaging system for groundwater detection.