excavation and retaining wall approximate costs

Hi,
I am after approximate excavation and retaining wall costs.
I am on the sunshine coast
approx. 360m3 of clay soil to be excavated.
4m high retaining wall, 13.5m wide
cheers
Anthony

My approximation would be shiploads of cash.

Yep, a shipload should cover it!

360m3 is heaps. Down here a "cheap" rate is $50/tonne for transport & dumping of soil, that's not including the excavation, you'd be looking at machine hire for that so maybe $500-$1000 per day.

The retaining wall is going to be a challenge. Not the length, the height. Normally you go down as far as you go up

A dozer will cost about $1,000/day plus transportation to and from the site.

Digging is the cheapest part.

These days off site disposal is expensive so if possible use cut and fill to eliminate off site disposal costs.
A 4m retaining wall will cause problems for you. It will need to be fully engineered, have water diversion drains and may need to be fenced (as fall protection).
I suggest that you consider terracing by having say 3 changes of level.

Alternatively, if you are excavating into rock or sandstone you may need to do nothing, Just batter back the excavation and eliminate the retaining wall.

Also have a soil test done including drilling some deep core holes to try and find out what surprises lie under the ground.

4m high retaining wall... you'll need a goldmine.
You better try to find out what's under your retaining wall first before getting to excited.

My retaining wall 22 metres across 2.1 metres high, then turns at both ends of block starting 2.1 metres high and ending one foot high 10 metres later for both sides of block, cost $20, 000 and obviously enginered.