Geoterra- Sulpher Block Walkway
LOCATION: Cremona, AB TIMEFRAME: Spring 2009 PRODUCT: GEOTERRA, LP16 Non-Woven Geotextile, Smooth HDPE 60 mil PROJECT PARTNERS: Owner: Shell Canada Energy Installation: Layfield
Shell’s Shantz sulphur forming facility is located 42 km downstream from the Caroline Gas Processing Plant. Sulphur is a by-product of the natural gas processing plant and is transported to the Shantz sulphur facility via a buried and heated pipeline. When global demand for sulphur declines, oil and gas producers store sulphur in big sulphur blocks. When demand improves the sulphur is remelted and processed in.
The sulphur storage at the Shell Shantz facility is divided into the East and West blocks. The West block is then divided down the middle with a walkway and pouring towers between the two sections of the West Block. Sulphur blocks pose a liability to their owners. The cost of treating and neutralizing acidic water that runs off sulphur blocks is high; therefore it is very important to install a containment system in place that prevents runoff from contaminating the soil.
In the Spring of 2009, Shell approached Layfield to build an inspection walkway between the two sulphur blocks to provide access to the sulphur pouring towers. The scope of the work included the installation of approximately 6,600 square meters of geomembrane liner over the existing asphalt inspection walkway that had degraded.
The liner selected for the walkway, a smooth HDPE liner, was very slippery. Hence, Shell requested a solution that allowed personnel to walk over the liner safely. The walkway had to be designed to control runoff from the block but it was also to be used by personnel to access the sulphur pouring towers.
To build the 280m long by 3m wide walkway between the two sections of the West block, Shell was considering using wood to build the walkway. After evaluating different alternatives, Layfield recommended the installation of a 2-inch Geoterra structural mat system over the liner. The Geoterra system is an integrated, open structural mat made of a polyethylene-blend material that is UV-stabilized. Geoterra is economical and long lasting as it does not corrode nor degrade. The Geoterra system was also selected because it is light weight, easy to handle and less labor intensive than other alternatives.
Layfield supplied and installed 6,600 square meters of 60 mil geomembrane liner with an LP16 non-woven geotextile to provide cushion and prevent aggregate from pressing through the liner. Once the liner was in place, Layfield installed the 2-inch Geoterra structural mat system. Curb blocks were used to keep the liner down and provide drainage around the west side of the block. Bracket tabs were welded on the liner and placed on a 3 meter spacing to prevent the Geoterra from sliding over the liner.
Shell was satisfied with the performance of the Geoterra system as it provided its personnel with safe passage along the sulphur pouring towers. Layfield was able to provide a long lasting walkway at a significantly low price.
The project was completed on time and on budget. Layfield Environmental Systems Ltd is a full-service geosynthetics installation contractor specializing in geomembranes, floating covers, and soil reinforcement geosynthetics. Layfield operates across Canada, the Western US, and internationally providing over 31 years of geosynthetic solutions.