The regional Commercial Audit Office at Calcutta was formed late in 1955 for auditing 8 Central Government and 17 State Government commercial concerns in West Bengal, Bihar, Orissa and Assam. With effect from 01.04.1969, the Commercial Audit Office, was upgraded as the Office of the Member, Audit Board & Ex–officio Director of Commercial Audit – I, Kolkata. Subsequently, the Office was re-designated as Office of the Principal Director of Commercial Audit & Ex–officio Member, Audit Board – I, Kolkata with effect from 28 th February 1990.On joining of Smt Suparna Deb , Director General ,on 23rd october2017 this office was again re-designed as O/o Director General of Commercial Audit ,Ex –Officio Member Audit Board -I, Kolkata and Director General of Audit (Mines), Kolkata.
Director General of Audit (Mines), Kolkata is responsible for audit of 57 Public Sector Enterprises and one Statutory Corporations, out of which 46 are audited as principal auditor and 11 as sub-auditor. Total 16 Autonomous Bodies under the jurisdiction of this office, 4 are audited as Principal Auditor and 12 are as sub-auditor.25 grants in Aid audit and 18 field offices of Govt of India This Office audits a mix of companies covering the fields of Mining, Heavy Engineering, Power, Dredging etc. Some of the major companies for which DGA (MINES), Kolkata is the Principal Auditor are ‘National Aluminium Corporation Ltd. (NALCO), ‘Balmer Lawrie & Co. Ltd.’ and ‘Hindustan Copper Ltd.’ (HCL). The important Autonomous Bodies (ABs) includes ‘Paradip Port Trust (PPT), Kolkata Port Trust (KPT), National Jute Board, Calcutta Dock Labour Board etc.
This office conducts the audit under section 13 & 15 and autonomous bodies under section 14 & 19, 19(2)/20 of CAG's (DPC) Act 1971. Besides, this office is also responsible for Finance audit, autonomous bodies, externally aided projects and expenditure audit of 18 field offices of various ministries.
• Branch office
This office has one branch office at Damoder valley corporation , Kolkata. Branch office, DVC (Hqrs.), conducts audit of accounts of Damodar Valley Corporation (Corporation). It is the sole auditor of the Corporation. Financial audit in respect of the Corporation is conducted by this office and observations on the financial statements, if any along-with reply of the auditee included in Audit Report of the Corporation in its Annual Report.
There are two Resident Audit Offices (RAO) at Durgapur Thermal Power Station, Durgapur and Chandrapura Thermal Power Stations, Chandrapura.