The paper showed the economic cost of a year of chaos in the world’s top bauxite exporter that began with a December 2008 coup and ended in a failed assassination bid on its leader.

The document revealed similar falls in output of other resources such as alumina, which together with bauxite form the backbone of the West African state’s economy and public finances.

Data for the first nine months of 2009, compared to the same period of 2008, show a fall of 22.9% in the total production of bauxite to 10.4Mt, stated the finance ministry paper.

Output in the third quarter was hit “among other things by institutional instability and a review of mining project contracts”, it said of moves by the junta to re-examine deals signed under late president Lansana Conte.

Income from projects run by mining majors including Alcoa, Rio Tinto and Rusal account for 80% of Guinea’s foreign currency reserves. Such revenues amounted to $149M in 2007.

The Alcoa-Rio venture CBG (Compagnie des Bauxites de Guinée), recorded bauxite output of 8.2Mt in the first nine months of 2009, said the report, a figure that compares with the record 13.7Mt it produced for the whole of 2008.

Output of alumina fell 25.3% in the first nine months of the year to 361kt.

The document did not detail why output of key resources had fallen. Mining firms have repatriated some non-essential staff but have said operations are proceeding as normal.