Choose correct network for underground device

Hello,
I am developing a network system for mine(depth of 2km and the tunnel’s length is about 200m). The system includes:

  • Data takers(estimated 200 units) to send signal data every 5 seconds (Data are 22 float variable/taker).
  • A MCU to receive data from data takers, do some calculation and send to ground.

Requirements:

  • Power supply will be battery and device should be able to operate for +2 years
  • Data takers and MCU connection must be wireless

The question is: Which module and network should I use ?

Current situation:
XBee S1 802.15.4
I am planning to use stand alone Xbees as data takers to send data to a (XBee + Arduino) and then from Arduinos send data to a Raspberry(connected with Xbee) for calculation. The Arduinos are there as I think it’s not possible to use only XBee and Raspberry (The range of XBee for indoor is 30m while my tunnel is 150-200m long).

Trung Van,

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Digi Support

Hello,
I email the sale support but after 1 email replied, I have been waiting for a week until now. Can anyone help me out?