[alma-site]Re: [alma-config]distance to pipeline

[John Conway]

Hi Bryan et al,

Right I think its good to pose the question
of close WE want to go the pipeline.
I think that 100m - 140m  to the pipeline sounds like 
like  a reasonable number from the point of view of 
both practically and configuration coverage. Having 
the limit less than this really doesn't help the resolution 
or uv covergae that much.

The fact that present designs press 
right up against the limit we have assumed doesn't imply 
that the limit is too loose, - these designs 
were all made assuming you have 
have a limited area and then optimised for maximum
resolution - this will always tend to force the pads
up against the limit - whatever it is (If we have 
a Y+ design instead then the bunching is 
not so severe. because  then your not effectifely
optimising in a limited 5km diameter  area).

I intend to have a design for all the pads
out to 5km diameter by early July so it would be 
good  to have a final spec for the pipeline 
guardband to work to. 

Gas Atacama seem to be fairly relaxed 
about this issue - but we need  to
clear this up with them. Could we get them to 
confirm that that they will agree to a
100m limit that we have been assuming up to now? 
And make written agreement
with them so its legally binding?  A limit
of 140m which they have implicitly accepted 
for APEX would also be OK from a configuration point of
view - what is more important than whether its
100m or 140m is to know which one it is so 
reasonably final pad positions can be produced
as soon as  possibe.

So in conlusion can we propose to them to confirm a  
100m limit and see what they say - if they are
not happy we can then suggest instead 140m using the 
test case of APEX.?
 

 John



On Tue, 14 May 2002, Bryan Butler wrote:

> 
> thanks for looking into this, eduardo.
> 
> this is good information, but begs the question:
> how close do _we_ want to get to the pipeline?
> 
> i would guess not closer than 50 meters, because we may need at
> least that much for foundation + access around the antennas (including
> the 7.5 meters protection band on each side).  100 meters is safer
> still.  but, we want to get as close as we dare to, because having
> that extra slop in the configuration design can really help (recall
> that all the designs push up against the pipeline boundary)...
> 
> who will make this decision?
> 
> 
> 	-bryan
> 
> 
> On 2002.05.13 13:44 Eduardo Hardy wrote:
> > The written agreement between NRAO and GasAtacama does not specify per
> > se a buffer zone but is designed so that we could have a 400 to 500 m
> > buffer, at our request. It simply specifies how much we and them have to
> > move away from the original positions in order not to interfere with
> > each other. The notion of a buffer appears in the minutes of the
> > negotiations conducted in Santiago in February 1998.
> > 
> > In principle (but see below), and since we were the ones requesting for
> > the buffer, I foresee no problem in getting closer to the pipeline, but
> > respecting of course the Chilean legal protection band 15 m wide
> > centered on the pipeline. I don't expect GasAtacama to object to this,
> > but we need to inform them in advance which I would do as soon as we
> > have a concrete proposal for the configuration. 
> > 
> > Please be aware that we might require a certain minimum distance to
> > assure cathodic protection. 
> > 
> > I have requested our lawyers to take a second look at our agreement and
> > advise me. I'm also requesting ESO (APEX) and the ASTE project to keep
> > us informed of any exchanges with GasAtacama.
> > 
> > Eduardo
> > 
> > Simon Radford wrote:
> > > 
> > > Today I interviewed Peter Napier and Jeff Kingsley, who were both involved in the negotiations with GasAtacama. Both recall a buffer zone of something like 400 m, although neither recall if thats +- 200 m or +- 400 m. I am attempting to track down the
> > > written agreement but had no luck today.
> > > 
> > > Simon
> > 
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