The functionality of lock bolt systems is based on cold forming/ extrusion technology. A so-called collar gets cold formed during installation by an anvil (part of a special installation tool) into unique locking grooves of a pin. After the installation the fastener is mechanical locked due to this volume controlled swaging process.
National Gas receives funding to develop Gravitricity underground hydrogen storage system
One single rock salt mine - Winsford - has 23 <i>MILLION </i>cubic metres of void and even allowing for 10% of that void set aside for hazardous waste...