Geotechnical Investigation includes surface exploration (geologic mapping, geophysical methods, and photogrammetry), and subsurface exploration (used to obtain information about soil conditions below the surface).

Surface investigations include preparation of topographic maps using the normal mapping techniques. All field surveys begin with preparation (or availability) of topographic maps showing elevation contours relative to some datum.

Geophysical surveys may help in the development of resources without the need for sampling. These surveys usually utilizes ground-based physical sensing techniques to produce detail image or map in a site. Thus, different methods can be used when conducting such surveys that fall under this category. With advancements in technology, geophysical surveys can also be carried out above the horizon.

Geological Maps and mappings are useful method to gather and present geological data in a specific site or area. It shows the distribution, location, and identification of rock types, soil types, and geological structures in relation to landforms and topography. These maps are helpful to predict and observe what lies below the Earth’s surface. Geological maps can be made out of aerial photographs, topographical bases, pace and compass, and chains.

Desktop surveys are considered to be the initial part of any site exploration and investigation program. This type of survey relies on investigation of existing records, texts, research,geological reports, maps, pollution reports, incidents, and any other relevant information regarding the area of interest. This initial survey is an important step to make a decision before proceeding to field-work and field based surveys.

Geochemical surveys are exploration techniques that is being applied in order to study the condition of the area based on geological samples present. Geological samples such as soil, rocks, sediments, and minerals are gathered and being sent to laboratories to study and provide relevant and vital information about different features such as rock types, rock and soil composition, and soil moisture which are vital to assess the capacity of an area to be a site for construction or to determine prospective mineralization zones.

The Seismoelectrical method is based on the generation of electromagnetic fields in soils and rocks by seismic waves. Although the method is not reported to detect groundwater flow, it does measure the hydraulic conductivity, which is related to permeability and therefore, to the potential to groundwater flow.

Ground Penetrating Radar (GPR) is a geophysical locating method that uses radio waves to capture images below the surface of the ground in a minimally invasive way. The huge advantage of GPR is that it allows crews to pinpoint the location of underground utilities without disturbing the ground. GPR uses energy waves in the microwave band, ranging in frequency between 1 to 1000 MHz. It requires two main pieces of equipment, a transmitter and receiving antenna. Ground Penetrating Radar works by emitting a pulse into the ground and recording the echoes that result from subsurface objects. GPR imaging devices also detect variation in the composition of the ground material.

Core Boring is a sampling technique used to research mineral resources in the subsoil by boring wells in order to analyze the ground, and for other digging activities for civil engineering purposes.

Core logging is the systematic recording and measuring of as such information as possible/ required to maintain the lithology (rock types), mineralogy, potential geologic history, structure, and alteration zones, through a tiny piece of cylindrical rock drilled and removed from a potential mineral deposit. Core logging is considered the primary method of determining grade, size , and mineability of a potential mineral deposit drill cores are relied on by exploration and mining companies around the world.