SRK has worked with Sirius Minerals (Sirius) on its polyhalite project in North Yorkshire, UK, since 2010. Sirius is currently constructing a deep shaft mine, around 1,500 m below ground level, to produce some 10 million tonnes of polyhalite per year in its first phase. We have been involved during the exploration, feasibility study, and now construction stages of the project.
We prepared and reported the first mineral resource estimate according to the JORC code in 2012. This reviewed the exploration work completed to date and assessed data quality, in particular the newly devised quality assurance and quality control system to ensure the polyhalite grades could be relied upon. We have developed the geological model to show a layered orebody comprising distinct high and low grade polyhalite horizons and gangue lithologies, which encompass all the major geological formations in the project area. Updates to the mineral resource estimates have been reported in 2016 and 2018.
In addition, we have undertaken geotechnical modelling work, ventilation engineering and production modelling, and mine design and schedules for the company’s feasibility study produced in 2016. From this, we reported ore reserves estimates in accordance with the JORC code. Mining is currently planned to be by room and pillar, excavated by continuous miners and with drill and blasting extracting rooms up to 40 m high. Our mining team has worked closely with equipment manufacturers and other specialists on the equipment design, layout, and costing for the project.
We prepared the Competent Person's report to support the company’s successful planning application and listing on the London Stock Exchange in 2017. In 2019, we prepared mineral resource and ore reserve estimates in accordance with the JORC code and a Competent Person's report to support the project’s second tranche of fundraising.
Our work preparing mineral resource and ore reserve estimates now forms the basis for the UK’s largest mining project currently under construction.
