Ministry of Environment and Forests guidelines stipulate that mining in quarries with lease area of 5-25 hectares should be done only manually.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/sand-mining-regulations-offer-ray-hope
[2] http://admin.indiaenvironmentportal.org.in/category/author/s-ganesan-0
[3] http://admin.indiaenvironmentportal.org.in/category/newspaper/hindu-chennai
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/ministry-environment-and-forests-moef
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/mining
[6] http://admin.indiaenvironmentportal.org.in/thesaurus/sand-mining
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/tamil-nadu
[8] http://admin.indiaenvironmentportal.org.in/thesaurus/environment-clearance-ec
[9] http://admin.indiaenvironmentportal.org.in/thesaurus/state-environment-impact-assessment-authority-seiaa
[10] http://admin.indiaenvironmentportal.org.in/category/thesaurus/tiruchirapalli-d
[11] http://admin.indiaenvironmentportal.org.in/category/thesaurus/karur-d