Just going to put this here after doing a search:

There have been several instances in the past where governments have overstated the value or extent of their natural resources.

Here are a few notable examples:

Venezuela's Orinoco Belt: In 2011, Venezuela claimed to have the world's largest oil reserves due to the heavy oil deposits in the Orinoco Belt. However, extraction has proven to be more challenging and expensive than initially stated.

Brazil's Pre-Salt Oil Fields:

In 2007, Brazil announced the discovery of massive offshore oil fields known as the "pre-salt" reserves. While significant, the reserves were not as vast as initially reported, and extraction has faced technical and economic challenges.

Russia's Arctic Oil and Gas: Russia has often touted the vast oil and gas reserves in its Arctic territories. However, the actual viability and accessibility of these resources have been called into question due to the harsh environment and technological limitations.

Afghanistan's Mineral Wealth:

In 2010, the U.S. Geological Survey, in collaboration with the Afghan government, announced that Afghanistan was sitting on nearly $1 trillion worth of mineral deposits. However, the country's instability and lack of infrastructure have hindered the development of these resources.

These examples demonstrate that initial reports of vast natural resource wealth do not always align with reality, and caution is often warranted when evaluating such claims.