April 11, 2016
Van Walt is proud to offer three mechanical systems for obtaining undisturbed soil samples down to 10m: the Van Walt Window Sampling System, the Lost Cone Drilling Set and the STITZ Coring set for soft sediments. All these systems make use of common components.
Recently our New Zealand office was on site with Environment Canterbury training a team in the use of the Lost Cone Drilling Set for the installation of monitoring wells. This system uses steel casing tubes which are driven down to the required depth. Once there, a standard 1-inch well is placed within the casing which is then extracted for re-use, leaving the well in place.
In a country where there are normally mountains and rivers between you and your neighbour a small drilling system like our Lost Cone Set comes into its own. The typical soil conditions in the area are quite variable but it is not uncommon to encounter glacial silts and gravel layers making manual drilling more tricky. The depth of the groundwater is typically 3 to 4 meters but higher levels of pollution caused by a huge expansion in dairy farming throughout the South Island which requires the intensive use of water, is putting increased pressure on environmental monitoring by the authorities who have a statutory responsibility under the Resource Management Act and the Local Government Act to protect water quality and quantity.
Environment Canterbury is the regional council working with the people of the City to manage the region’s air, water and land. They are committed to care for Canterbury’s resources and achieve a sustainable environment while promoting the region’s economic, social and cultural well-being. Working in partnership with communities they encourage the management of natural and physical resources by using innovative, cost-effective and technically excellent approaches to monitoring and research that ensures any decision making is based on high quality information and results.
Environment Canterbury has used drilling contractors to install wells but, with a need to install shallow monitoring wells on a more regular basis, the team were looking for a more flexible solution.
The Lost Cone Drilling Set will do just that. It is a fast and efficient way to install a monitoring well and it works particularly well in stonier soils and gravels. A specially designed cast iron cone (which is left in the ground) is mechanically hammered into the soil to produce a very straight bore hole. Many components of the Lost Cone Drilling set are common to our standard Window Sampling System which allows for the sample to be captured either in the open samplers or in a closed liner option.
When working in weak sediments, also below the water table and when there is a risk that the drilled hole collapses then we would recommend the STITZ corer option; a lined sampler which can be driven into the sediment in a closed position and only opened when the desired horizon is reached.
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A small selection of our environmental equipment