|
|
|
|
|
 |
Geo-Physical Survey: |
| Geophysical survey refers to the systematic collection of geophysical data for spatial studies. Geophysical surveys may use a great variety of sensing instruments, and data may be collected from above or below the Earth's surface or from aerial or marine platforms. Geophysical surveys have many applications in Earth science, archaeology, and engineering. Many disciplines have developed unique methods and terminology. |
|
|
|
 |
|
|
|
|
|
Water Well Drilling: |
| The water well drilling industry includes more than 8,000 establishments operating roughly 19,000 drilling rigs in the early 2000s. These establishments had total employment of 25,539 in 2002, according to the U.S. Bureau of Labor Statistics. Average hourly wages for water well drillers totaled $12.77 in 2002. |
|
| The nation's water supply comes from surface sources such as lakes, rivers, and streams, in addition to vast underground aquifers. Groundwater has often been preferred over surface water for use in homes and industry because it is relatively inexpensive to develop and treat, it contains no sediment, its chemical quality remains constant, and facilities to develop it can be situated on small plots of ground. Of the 408 trillion gallons of water consumed daily in the United States in the early 2000s, nearly 20 percent was ground water. |
|
|
|
|
|
|
|
|
|
Exploratory Drilling: |
| Search for an undiscovered reservoir of oil or gas-a very risky undertaking. Exploratory wells are called wildcat (in an unproven area); controlled wildcat (in an area outside the proven limits of an existing field); or deep test (within a proven field but to unproven depths). Exploratory drilling programs are usually syndicated, and units are sold to limited partners. |
|
|
|
|
|
|
|
|
|
De Watering: |
| Dewatering is the removal of water from solid material or soil by wet classification, centrifugation, filtration, or similar solid-liquid separation processes. Removing or draining water from a riverbed, construction site, caisson, or mine shaft, by pumping or evaporation. This is often done during the site development phase of a major construction project due to a high water table. Usually involves the use of "dewatering" pumps. Methods of dewatering include; Wellpoint, Deep Well and Eductor systems. |
|
| Under certain conditions, a wellpoint system often proves not only to be an effective means of dewatering, but also an economical one. Wellpoint systems are particularly effective in stratified soils or where draw down must be achieved close to bedrock. Features and advantages of wellpoint systems include: |
|
 |
Ground water control near ground surface to a depth of up to 20'. |
|
More effective dewatering when clay conditions are present at or near invert. |
|
The ability to install dewatering systems where access with drill rigs is impossible. |
|
|
|
|
|
|
|
|
|
Core Drilling: |
| A core drill is a drill specifically designed to remove a cylinder of material, much like a hole saw. The material left inside the drill bit is referred to as the core. |
|
| Core drills are used for many applications, either where the core needs to be preserved (the drilling apparatus used in obtaining a core sample is often referred to as a corer), or where drilling can be done more rapidly since much less material needs to be removed than with a standard bit. This is the reason that diamond-tipped core drills are commonly used in construction to create holes for pipes, manholes, and other large-diameter penetrations in concrete or stone. |
|
| Core drills are used frequently in mineral exploration where the coring may be several hundred to several thousand feet in length. The core samples are recovered and examined by geologists for mineral percentages and stratigraphic contact points. This gives exploration companies the information necessary to begin or abandon mining operations in a particular area. |
|
|
Air core drilling |
| |
Air core drilling and related methods use hardened steel or tungsten blades to bore a hole into unconsolidated ground. The drill bit has three blades arranged around the bit head, which cut the unconsolidated ground. The rods are hollow and contain an inner tube which sits inside the hollow outer rod barrel. The drill cuttings are removed by injection of compressed air into the hole via the annular area between the innertube and the drill rod. The cuttings are then blown back to surface up the inner tube where they pass through the sample separating system and are collected if needed. Drilling continues with the addition of rods to the top of the drill string. Air core drilling can occasionally produce small chunks of cored rock. |
|
| |
This method of drilling is used to drill the weathered regolith, as the drill rig and steel or tungsten blades cannot penetrate fresh rock. Where possible, air core drilling is preferred over RAB drilling as it provides a more representative sample. Air core drilling can achieve depths approaching 300 meters in good conditions. As the cuttings are removed inside the rods and are less prone to contamination compared to conventional drilling where the cuttings pass to the surface via outside return between the outside of the drill rob and the walls of the hole. This method is more costly and slower than RAB. |
|
|
Deep well dewatering |
| |
These systems are beneficial for dewatering to depths at which suction lift limitations prevent the use of wellpoint pumps. Deep wells also offer the ability to control large volumes of water. Other features and advantages of deep wells and the deep well system include: |
|
| |
|
Installation of 20' to 100' deep wells |
|
Installation of wells far enough from the excavation so as to not be obstructive. |
|
Ability to penetrate strata impervious to the jetting method of wellpoint systems. |
|
Under proper soil conditions, deep wells allow for drainage of large areas. |
|
| |
|
|
|
|
|
|
|
|
|
|
Complete Water System: |
| A good clean water supply and adequate sanitation system are considered to be the most important factors in ensuring good health in a community. Improved water supply and sanitation systems were major elements of the public health measures that drastically cut death rates and improved health levels in the industrialized countries. Though it is not generally appreciated, these measures have been considerably more important than curative medicine in contributing to good health, long life expectancy and low infant mortality. Infant diarrhea, the largest killer in developing countries, is closely related to poor water quality. |
|
|
|
|
|
Top |
|
|
|
|
|
|
|
