See there are 2 ways to this issue

1. Contractor can revise the schedule back to planned finish date (baseline finish date) leaving out the 2 months but main contractor will make a document that will show to employer the cost of compressing the schedule by 2 months and this wil not involve EOT but employer will pay for this compression amount.

2. But if main contractor wants to have EoT, then they will make a new schdule with TIA method that will indicate that 2 months was delayed by employer on a particular activity. This will involve creation of new activity like " Delay - Excavation works activity ", original duration should be 2 months and actual duration should be 2 months. Then you can run the schedule and generate a new finish date. Take new finish date minus old finish date (from without any delay schedule) to give you actual number of days (that employer will pay as an extension of time) which may be less, equal or more than 2 months depending on the lag that exist on the schedule.

Prolongation cost will come here

TN: Employer can ask for revise schedule whether he caused the delay or not.

If employer causes the delay, then cost of compresing the schedule will be paid by employer. 

But if contractor causes the delay, and employer ask to revise back to original or earlier finish date, then contractor will pay for the cost to maintain the original date

as Rafael points out usually there is a clause in the contract about timely notice of delay. This can be argued by the employer but may not hold much water in a court of law especaily if there is other documentation such as meeting minutes that states that there was an on going delay. 

The purpose if of the immediate notification for the delay gives the employer the opportunity to try to limit any further delay and possibly to do something different to recover from the dealy. Uless someone tells him there is a delay thru proper notification then he thinks everything is going well. Maybe with proper notificaiton the 2 month delay could have been reduced to a 1 month delay.

Even if the contractor does not know the total extent on the delay he can put the employer on notice informing him that there is a delay and the the total delay time will be quantified at the end of the delay. This markes a place in the sand. 

In any event the supporting documentation to support the EOT must be submitted. An EOT can not just be granted without supporting evidence. The justification should be well documented to support the EOT. If the employer knows that this was his delay then there should not be any problems granting the EOT once the supporting evidence is submitted/reviewed and approved. 

Hi Prageeth

Yes - approval will mean acceptance of the EoT.

Lack of notice or detailed claim should not prevent the contractor from being granted an EoT.

If the employer caused the delay and does not award a reasonable EoT then he is in danger of setting time at large and losing all his rights to deduct LAD's.

It is your duty to protect the employer from that eventuality.

Best regards

Mike Testro