1. Minerals are needed for the construction of transport and renewable energy infrastructure, housing and other buildings that are a vital part of the Scottish Government's infrastructure investment plans for the future. Scottish Planning Policy ( SPP) sets out planning policies that are intended to ensure that a steady supply of material is maintained to meet the needs of society and the economy in an acceptable and sustainable manner. The most important sources for aggregates in Scotland are crushed rock (from igneous rock, sandstone and limestone) and sand and gravel. The British Geological Survey ( BGS)'s Mineral Planning Factsheet: Construction Aggregates  provides further information on the supply and demand of aggregates in the UK.