[Proj] Lease block definition

[Gerald I. Evenden]

A few weeks ago the item of oil lease blocks came up as an item to be plotted 
on extended range TM maps.  My encounter with lease blocks was only as a 
short spectator of someone digitizing the irregular shore boundaries of said 
lease blocks.

My understanding is that the lease block boundaries are established in terms 
of UTM grid coordinates?  If so, what are the typical side lengths in meters?

My recollection was that one of the reasons for selecting TM for large area 
mapping was because of "facilitating" the plotting of lease blocks.  True, 
false?

Any information related to what has been done or proposed for large region 
mapping with TM would be appreciated.
-- 
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist