Issue

Andvare were asked to complete an Engineering assessment and third party review of the suitability of four proposed equipment types to unload dredged material from barges onto large articulated trucks. The Client had a number of possible options that they believed warranted further investigation including:

• 90t long reach excavators
• Crawler cranes
• Fixed cargo cranes
• Specialised material handlers

However, with a lack of clearly defined and consistent information across the different types of equipment, the Client could not adequately and fairly compare between options to determine which equipment best suited their requirements both for this project and in the future.

Solution

Andvare developed a time-motion study to determine the ability of each type of machine to meet the desired throughput. This study identified critical operational parameters to ensure that each machine selected could adequately meet the client requirements including:

• Bucket size
• Filling factors
• Calculated cycle times
• Allowances for real work efficiency and availability
• Fuel/electricity consumption rate

Andvare then assessed each of the four machine types nominated by the Client for unloading bulk materials by developing a weighted comparison matrix for criteria nominated known to be of relevance to our client. These consisted of:

• Capital costs
• Calculated operational costs
• Net cost per tonne of material unloaded
• Maximum and average operational throughput
• Reliability

Finally, Andvare identified an opportunity for improvement on the proposed truck haulage plan. A full capital and operational cost estimate were completed for utilising different sized trucks along the proposed haulage routes to the reclamation area.  From this a cost per tonne was developed and a clear indicator provided to the client of the most efficient option.

Benefits

• The calculation of the net cost per tonne of material dredged allowed the client to eliminate the cost prohibitive unloading methods.
• By producing full weighted comparison matrix, the overall value of the equipment to the client could be easily compared against other options with similar overall costs, ensuring that the full equipment life cycle was taken into consideration.
• The matrix clearly eliminated two options, however, allowed client discretion when it came to the final choice between the remaining options.

The haulage optimisation study led to the identification of over $10 million in potential savings to the Client over the course of the dredging program.