Tender rates are often quoted as between 20 and 25 m3/hr. With adequate supervision and sufficient loose spoil material supplied to the crane drop area, these rates can easily be increased. Grabs mounted on crawler cranes, rates depend on...

• Depth of the spoil to be removed
• Operative supervision - breaks etc
• Management and availibility of lorries
• Efficiency and utlisation of banksmen
• Transport of spoil to crane drop area
• Down time of machinery and staff

Clamshell Grab Mounted on a crawler crane... 2.0 m3 bucket (HK Cut & Cover Tunnels)

• 33 m3/hr
• 1.5 m3 per lift
• 2.9 mins per lift

2.5 m3 bucket (HK Station Box)

• 41 m3/hr
• 2.0 m3 per lift
• 3.1 mins per lift