Nabarlek Pit decommissioning migration of sulphate, nitrate and radium ions in groundwater - preliminary modelling
E-Publications; E-Books; PublicationNT; Report ; 41/1984
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Dept. of Transport and Works
Report ; 41/1984
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Technical Report WRD84041 Viewed at 14:07:09 on 29/07/2010 Page 5 of 34. I I I I I I I I I I I I I I I I I I I I I 3. LONG TERN NODEL FOR RADIUN 3.1 Development o~ an Analytical Solution Groundwater movement near the pit at Nabarlek takes place within discrete fractures in schistose rocks. These fractures can be envisaged as consisting of an indeterminate number of tubes which connect a source of pollution (the pit) to a discharge point (Cooper Creek) . Water enters these tubes containing high concentrations cf radium, and radium is progressively lost by rock adsorption and radioactive decay with distance along each tube. The question is, '''hat will the radium concentration in groundwater be as a function of time and distance from the pit, and will significant levels of radium be discharged into Cooper Creek? To simplify the solution to this problem, all water leaving the pit will be considered to pass through a slngle tube. Consider a single tube: p Q G -> dV y y+dy A given concentration flow rate, G, of radium enters the groundwater flow tube from the pit. At point P, fraction y of radium has been lost from solution by adsorption and radioactive decay. After a small volume increment, dV, fraction y+dy of radium has been lost from solution. If r is the rate at which radium ions are lost from solution per unit volume increment, then SA2/11:TJ