expired live tenements

whats the go with live tenements that have expired ie gone past there expire date
that are then showing up blue as a pending lease, but they also show up green as a live lease
most of the time its the same company/person that has the pending
are you allowed to go on the lease if it's past the end date

Short answer. No.

When a prospecting (P) lease nears its expiry it can under certain circumstances, be converted to a mining (M) lease. While the M is pending the underlying P is continued as an extension until a decision is made on the M. Approve the M and it becomes live or not approve the M and the land reverts to unallocated.
While the approval process is going on the area will be crosshatched with blue and green and it is not available for general public prospecting. The same applies when an SPL is pegged over part of another live lease. The underlyying lease is still live so no general public prospecting is allowed.
Have a look at P39/4550 which expired on 22 Oct 2016. M39/1108 was applied for on 17 Oct 2016 so while it is being assessed the DMP has added time to P39/4550. Look it up under the dealings tab on Emits. While it is being assessed it shows up on Tengraph as crosshatched green and blue.
I am sure the leasee won't mind me using that lease as an example as he actively patrols his leases anyway. There are numerous other examples around the Cardinia area where Kin Mining is converting P's to M's.
It seems confusing but once you get your head around it, it actually makes sense.

thanks for the replies fellas, guess that counts those blocks out