Two firms allegedly involved in illegal mining have taken out of the country, over the years, minerals worth over N100 billion.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/two-illegal-mining-firms-defraud-government-n100-billion
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/guardian-nigeria
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/mining
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/illegal-trade
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/nigeria
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/africa