ESI, now part of Stantec, have been retained by Sirius Minerals to provide specialist groundwater modelling services since 2013. Initially employed to provide technical support to the Environmental Statement (ES) and planning application, we are now assisting with water-related construction and design matters.
The Woodsmith mine is located near Whitby. It will target the largest, highest grade resource of polyhalite to be found anywhere in the world. The results of over 16,000 m of drilling carried out since 2011 indicate that there is a Probable Mineral Reserve of 250 million tonnes of polyhalite within the resource area.
Challenging Hydrogeological Conditions
The site lies within the North York Moors National Park and is located next to a water sensitive Special Area of Conservation (SAC). Groundwater is found within a multiple aquifer system of relatively thin, alternating Jurassic sandstones and siltstones/ mudstones. Springs feed local watercourses, wet heath habitat and provide local water supply.
Assessing the impacts of development in such conditions can be challenging.
To support the planning application and inform the ES we prepared a multi-layer numerical groundwater model to simulate the effects of construction elements and dewatered excavations.
Following the successful granting of planning permission, we have developed the model further to assist construction planning including the design of an effective dewatering arrangement.
The model has been refined over time to allow for new data and grid refinement (using Modflow-USG) in areas of interest.