SQL Server CTE average with conditions - sql

Question

I've been trying to visualise how to do this with a CTE as it appears on the surface to be the best way but just can't get it going. Maybe it needs a temp table as well. I am using SQL Server 2008 R2.
I need to create intercepts (a length along a line essentially) with the following parameters.
The average of the intercept must be greater than .7
The aim is to get the largest intercept possible
There can be up to 2 consecutive meters of values less than .7 (internal waste) but no more
There is no limit to the total internal waste within an intercept
There is no minimum intercept length (well there is but I'll take care of it later)
Note: there will be no gaps as I has taken care of that and the from and to can be decimal
An example is shown here:
enter image description here
In space seen here with the assay on the left and depth on right:
enter image description here
So for a little more clarity if needed, intervals 6 to 7 and 17 to 18 do not make part of the larger intercept as the internal waste (7-9 and/or 15-17) would bring the average below 0.7 - not because of the amount of internal waste.
However the result for 21-22 is not included because there are 3 meters of internal waste between it and the result for 17-18.
Note that there are multiple sites and areas which make part of the original tables primary key so I imagine that a partition of area and site would be used in any ROW_NUMBER OVER statements
Edit: the original code had errors in the from and to (multiple 14 to 15) which would have been confusing sorry. There will be no overlapping from-to's which hopefully simplifies things.
Example values to use:
create table #temp_inter (
area nvarchar(10),
site_ID nvarchar(10),
d_from decimal (18,3),
d_to decimal (18,3),
assay decimal (18,3))
insert into #temp_inter
values ('area_1','abc','0','5','0'),
('area_1','abc','5','6','0.165'),
('area_1','abc','6','7','0.761'),
('area_1','abc','7','8','0.321'),
('area_1','abc','8','9','0.292'),
('area_1','abc','9','10','1.135'),
('area_1','abc','10','11','0.225'),
('area_1','abc','11','12','0.983'),
('area_1','abc','12','13','0.118'),
('area_1','abc','13','14','0.438'),
('area_1','abc','14','15','0.71'),
('area_1','abc','15','16','0.65'),
('area_1','abc','16','17','2'),
('area_1','abc','17','18','0.367'),
('area_1','abc','18','19','0.047'),
('area_1','abc','19','20','0.71'),
('area_1','abc','20','21','0'),
('area_1','abc','21','22','0'),
('area_1','abc','22','23','0'),
('area_1','abc','23','24','2'),
('area_1','abc','24','25','0'),
('area_1','abc','25','26','0'),
('area_1','abc','26','30','0'),
('area_2','zzz','0','5','0'),
('area_2','zzz','5','6','1.165'),
('area_2','zzz','6','7','0.396'),
('area_2','zzz','7','8','0.46'),
('area_2','zzz','8','9','0.111'),
('area_2','zzz','9','10','0.053'),
('area_2','zzz','10','11','0.057'),
('area_2','zzz','11','12','0.055'),
('area_2','zzz','12','13','0.03'),
('area_2','zzz','13','14','0.026'),
('area_2','zzz','14','15','0.194'),
('area_2','zzz','15','16','0.367'),
('area_2','zzz','16','17','0.431'),
('area_2','zzz','17','18','0.341'),
('area_2','zzz','18','19','0.071'),
('area_2','zzz','19','20','0.26'),
('area_2','zzz','20','21','0.659'),
('area_2','zzz','21','22','0.602'),
('area_2','zzz','22','23','2.436'),
('area_2','zzz','23','24','0.874'),
('area_2','zzz','24','25','3.173'),
('area_2','zzz','25','26','0.179'),
('area_2','zzz','26','27','0.065'),
('area_2','zzz','27','28','0.024'),
('area_2','zzz','28','29','0')