 |
|
|
|
 |
|
 |
 |
 |
 |
||||||
 |
 |
 |
 |
 |
|||||
|
|
|
|
|
|
|
|
|
|
Environmental - Drilling Services
DIRECT PUSH SOIL SAMPLING
Direct push sampling utilises a percussive top drive hammer to drive a dual tube sampling system into unconsolidated formations. The sample is undisturbed and recovered in 1.2m polyvinyl tubes. The tube can be opened on location for transfer to a secondary storage medium or retained in the tube for removal at a later stage.
Depending on the formation this method of sampling is effective at up to 15m depth. Advantages of such sampling methods include speed, maximum sample integrity, reduced cost of managing and removing drilling spoil and easy, accurate bore logging.
Small diameter “Pre-Packed” wells can additionally be installed through the direct push system in formations that are likely to collapse or when attempts are being made to reduce drilling waste.
Pre-packed wells have a maximum ID of have a 30mm though it ensures an effective gravel pack in conditions that would otherwise compromise a traditionally installation methods.
TopSOILD AUGER DRILLING
Solid augers are effective in drilling soft to medium formations such as clays and weathered sedimentary rocks. Solid augering often follows direct push sampling to increase bore diameter to allow the installation of monitoring wells. They are a fast and efficient method of drilling small diameter bores without introducing any drilling fluids into the bore. Solid augering is not effective in formations that are prone to collapse as there is no means of keeping the bore clean for well installation. Solid augers can be effective up to depths of 40m.
TopHOLLOW AUGER DRILLING
Hollow augers are used when formations are prone to collapse. The well is installed prior to removing the augers. This allows for the installation of an effective gravel pack around the screen which would not be possible with solids. The maximum ID well that can be installed with hollow augers is 100mm. Due to the large diameter of the hollow augers the drilling process is usually slower and the spoil created is more significant. Maximum depths drilled with hollow augers are around 25m depending on conditions and the size of the auger.
TopROTARY AIR HAMMER
A rotary down hole hammer is used in conjunction with a high volume, high pressure air compressor for drilling in rock. Down hole hammers can be used to drill bores from 80mm – 200mm in diameter. Dust suppression units can be supplied for use in sensitive areas. Down hole hammers are effective up to depths of 100m.
TopDIRECT INJECTION (REMEDIATION PRODUCTS)
The direct push technology used on our Geoprobe machines can be utilised as an injection medium for remediation products such as ORC. Using specialised mixing equipment and powerful pumps, large quantities of these materials can be injected at varying pressures and depths without creating any drilling spoil. “Spears” with specially designed pressure injection points are pushed or hammered in to the ground and the attached to pumping equipment.
TopCONCRETE CUTTING
For drilling operations of sites with cement slabs, concrete coring equipment is available to all crews. Coring the concrete slab allows for hand augering of the first 1- 2m ensuring safe clearance of services.
TopDECONTAMINATION
All rigs come equipped with high pressure washers for the decontamination of down-hole equipment between drilling locations and of the rig prior to leaving site. Water is carried on all support vehicles so there is no need to provide access to water on site.
TopMONITORING / EXTRACTION / INJECTION WELLS
Numac drilling supplies high quality well installation materials that meet all necessary requirements to comply with Australia’s “Minimum construction standards for bores”.
We supply:- 50mm PVC class 18 casing & Screen.
- 100mm PVC class 12 casing & Screen.
- Cast iron well heads.
- Monument (standing) well covers.
- Washed and graded gravel pack.
- Bentonite (chips & Granular).
- Builders cement (grout).
- Rapid set cement.
- Lockable well caps (with vapour extraction points if necessary). (J&H styles).
- Pre-packed wells up to 37mm Internal Diameter
Although we have a standardised installation model for 50mm and 100mm monitoring wells we can design wells to suit specific site requirements eg. Stainless steel screens in highly corrosive environments.
TopWELL DECOMISSIONING
Once a monitoring well has reached the end of its useful life it must be decommissioned. An application must be lodged to the relevant water authority to gain approval to decommission a well.
The process of decommissioning wells can vary depending on its installation. In most cases environmental monitoring wells are filled with a cement/bentonite mix. This grout slurry is pumped into the bottom of the well up to the surface. The density of the cement slurry displaces any water currently in the well and ensures the entire column is filled solely with the desired cement & Bentonite mix.
In some circumstances it may be necessary to “pressure grout” the well. In this instance the grout slurry is pumped under pressure into the well forcing a predetermined amount of the mix out through the screen and into the annular space. This is not required under in normal circumstances though can be completed as an extra safeguard where there is a considerable risk of cross contamination.
Top