Renison Goldfields Consolidated Limited, Pine Creek Project. Groundwater Investigation Stage 2, Establishment of Borefield and Management Studies. Report H114/3-AA.
Coffey & Partners Pty Ltd
E-Publications; E-Books; PublicationNT; Report no. 87/1984
1983-11-01
Date:1983-11
English
Northern Territory Government
Darwin
Report no. 87/1984
application/pdf
Attribution International 4.0 (CC BY 4.0)
Northern Territory Government
https://creativecommons.org/licenses/by/4.0/
https://hdl.handle.net/10070/228435
https://hdl.handle.net/10070/674167
Technical Report WRD84087 Viewed at 14:07:14 on 29/07/2010 Page 74 of 167. I , I I I I I I I I I I I I : I I ~ , I I H1l4/1-MRS Nov 26, 1983 44. - --~ ~-~ .---~-~~---------~_i 7.3.5 Groundwater Recharge 7.4 Two mechanisms contribute to recharge of the groilllcwater hystem in the im.-nediate mine-to .... n area. (a ) groundwat~r throughflow derived from continual movement of wate~ through the system (b) vertical infiltration of rainfall during the wet season Both mechanisms r in some Hay sup-port sustai11ed pumping from the town borefield to meet domestic requirements, although it would appear that the throughflow component is f ai rl y small. Previous monitoring oy the i)TW has shown the groundwater system to L, extremely responsive to recharge eftects as illustrated in Figure 17. Based on data recorded during 1982-1983, the recharge response can show lug times of 2 to 3 months following rains, ioiith LI ,> main response occuring during Februa~ and Ma~ch. The extent of the seasonal fluctuation, as shown on Fig. 17 suggests tth1t during the dry season, groundw~tcr is drilwn tno1J.nly by derlctinq storaq0, rather than by capture of throughflow. Due to both limited aquifer sto:r-age and groundwat?r depIction due to natura] and artificial discharge., periodic aC!uifcr recharge is essential to sustain pumping. Town Barefield Present water supplies for the townsite are pu.'1lped ft"om 4 or 5 bores located as shown on Fig. 19. Nhi Ie most of these bores have been rated to supply 0.75 - 1 l/sec each, actua.l yicld~ are oftc:1 as slow as 0.3 l/sec r (field records). [t. nillr"j-.)er of the b()res are also p::"one '.::.0 1 falking! 1 particulal.ly t.owards the end of the dry season. Fig. 19 illustrates the pattern of groundwater rnOVf>fTlf!nt toward~ the existing bores, and delineates the zone of influence of the town borefield on the ~ater table due to pumping. The shape of this zone of influence, and the general form {~)r the contours suggests a significant proportion of the fluw sustaining Dumping is derived from a::"eas north and south of the present borcfield4 Due to stronq aquifer anisotrr'py it is tho'lqht that weak hydraulic gradients frow the NH and SE t(,'nd to be masked due to the permeability co~trasts and stee;:> hydraulic gradient d8veloped across strike.