Homestake Telecon, 11/14/2013

Attending: Eric, Riccardo, Vuk, Tanner, Gwynne, Victor, Gary

0) Homestake wiki ready to use, everyone should check that they have read/write access to it.

https://zzz.physics.umn.edu/groups/homestake/home

1) Status at Homestake (Vuk, Victor, Tanner) Discussed the possible locations, described in

https://zzz.physics.umn.edu/_media/groups/homestake/array/locations_preferences_v2.pdf

Upshot: several locations of interest at 4850, will try to go for all of them, although some of them are near active places, such as the Davis campus. At 4100, one location is simple (Bill's station), but close to an existing station. Possibly another station could be pursued if costs allow. At 2000 there is a good location NW from the existing ones, but close to a stope that may impact the waves at higher frequencies. At 1700 there are several locations of interest, some giving a large extension of the array towards NW. Need to get better cost estimates before we can decide which of them we could pursue. Two locations have been found at 800, but they are expensive because of the lack of power on that level.

Vuk to send coordinates to Gary, so that he can look at the possible surface locations.

Vuk: would it be possible to operate the stations off of batteries? What are the costs, livetimes, duty cycles? If so, this could be a substantial cost saver, compared to running power cables over long distances.

Gary/Riccardo: Yes. Deep charge batteries are commonly used for this type of purpose, an $80 battery could last at least 4-6 weeks. Could use several of them to last for ~6 months. Could recharge them with a diesel generator (~$1000-2000 cost), or could simply replace the batteries and recharge on the surface or somewhere near the shaft. Carrying them around may be difficult, but if rail is available it should not be a big time and manpower requirement (especially if we only need to replace batteries twice a year).

Vuk/Victor: could consider buying ~100 batteries for ~$10k, which should allow us to operate all our underground stations for 6 months before recharging…

Vuk: will check with SURF whether there are any restrictions regarding the use of batteries underground, use of diesel generators etc. ALso will try to estimate what fraction of the projected stations costs are due to power cables.

Vuk: need to deal with the GPS/timing issue, which will likely also require additional equipment and a power source.

We did not have time to address the remaining items on the agenda.

2) PASSCAL communications (Vuk, Gary)

  a) availability of instruments
  b) timing/synchronization

3) UMN test setup (Tanner)

4) Analysis of existing data

  a) Frames/miniSEED files (Shivaraj, Tanner, Michael)
  b) Wiener filtering (Michael, Jan)
  c) Estimation algorithms (Shivaraj)