The survey is being conducted with Digital Global Positioning System (DGPS), an instrument that gives an accurate data about the encroachments, said Director of Mines Prasanna Acharya.
The M B Shah panel in its report on illegal mining in Goa had pointed out that there are as many as 100 mining leases that have encroached outside the demarcated areas.
However, the miners contested the Google maps saying the Shah Commission has "wrongly" mapped these areas.
Goa Mineral Ore Exporters Association (GMOEA), an association representing exporters and miners, had said that some adjacent leases were shown as encroachment by the Commission in its report.
Acharya said the DGPS survey of first five leases, all of them owned by Sesa Goa Limited, would be completed by October 13. "Once we get the first report on five leases, we will continue with rest 95 leases," he added.
According to Shah panel, the mine owners by encroaching outside their areas had extracted ore worth Rs 35,000 crore, which needs to be recovered from them.
Goa Mines and Geology Department earlier this week had issued show-cause notices to all the 100 mining leases asking them why action should not be initiated against them.
The lease-holders are given time till October 22 to respond to the notices.
