The presence or extent of proven oil reserves in Somalia is uncertain. There are costs in maintaining large currency reserves. Kuwait has about of recoverable oil reserves. Kazakhstan holds about of proven recoverable oil reserves and of gas. The estimated total reserves of lignite coal that month was . This amount represented of total U.S. gold reserves, which were at that time. India has abundant domestic reserves of coal. Restrictions apply for nature reserves and other protected areas. Texas has of proven crude oil reserves. There are formal estimates of the possible reserves of oil discovered. Amazonas has most of its land occupied by forest reserves and water. The deposit is equivalent to 25 percent of known world reserves. Marius found Rome's traditional manpower reserves depleted. Sichuan accounts for almost half of the known natural gas reserves and production. There is some disagreement on which country has the largest proven gas reserves.