The company has consents from the Otago Regional Council, and a mining permit and access agreement from Land Information New Zealand, but has applied to the Central Otago District Council (CODC) for further consents.
District council planning and environment manager Louise van der Voort said the need for the consent was brought to the council's attention by person living beside the river who inquired about noise levels.
On checking the district plan, council staff discovered the need for a regional council consent for the dredge triggered a rule in the plan.
Under the plan, commercially operated vessels over 6m long need consent except for suction dredges, which are permitted under the regional water plan. But because regional council consent is needed, that exemption does not apply.
The application says the district council was consulted during the regional council consent application process.
The 24m suction dredge was launched just below the Roxburgh Dam in February 2012 but experienced teething problems.
It was taken off the water near Ettrick in October last year, with six staff made redundant, and relaunched in August.
Under Maritime New Zealand rules, the vessel must be ''slipped'' for survey, any repairs and/or alterations, the application says.
The company (CGCL) has been granted land use consent by the Otago Regional Council to form an access track to the river and erect a temporary slipway.
''It is CGCL understanding that this may also require CODC consent,'' the application says.
It also says noise testing is being undertaken and an additional report will follow.
Regional council consented operating hours are 7am to 10pm seven days a week with extra restrictions over Christmas-New Year and Easter holiday. The application states the nature of the activity has an environmental impact - riverbed gravel is sucked up, sorted and returned to the river about 20m downstream, disturbing the natural riverbed.
Conditions imposed in regional council consents attempt to mitigate, minimise or avoid those and other impacts.
The company has consents to operate the length of the Clutha River from just below Roxburgh township to Tuapeka Mouth.
The application states the current operating area is between Dumbarton and Millers Flat ''but this application is for the entire permitted area''.
The district council's patch finishes at Raes Junction.
Clutha District Council planning and environment manager Murray Brass said as far as he knew, the council had not been approached by Cold Gold Clutha.
His council did not have a rule in its district plan like the Central Otago council and ''generally speaking'' the dredge's operation on the waterway would not need a consent from his council. It was, however, possible the company would need consent to create any slipways needed.
A copy of the company's consent application to the regional council to create the temporary slipway near Ettrick, which is included in the application to the Central Otago council, says the company needs to be able to launch and remove the dredge from the river regularly.
The application to the Central Otago District Council is open for public submission until November 15.
