Venezuela has some of the largest gold deposits in South America along it’s river beds.  For this reason the gold and diamonds don’t require mining equiptment that is industrial.  Small scale mining operations are common but you have to be caitions when mining or Placer mining in Venezuela.  For those of you who are unfamiliar with Placer mining you could take a look at wiki which would tell you the following:
According to Wikipedia Placer mining is “the mining of stream bed deposits for minerals. This may be done by open-pit (also called open-cast mining) or by various surface excavating equipment or tunnelling equipment. Placer mining is frequently used for precious metal deposits (particularly gold) and gemstones, both of which are often found in alluvial deposits—deposits of sand and gravel in modern or ancient stream beds, or occasionally glacial deposits. The metal or gemstones, having been movstream flow from an original source such as a vein, are typically only a minuscule portion of the total deposit.
Since gems and heavy metals like gold are considerably more dense than sand, they tend to accumulate at the base of placer deposits.  It is important to note that placer deposits can be as young as a few years old, such as the Canadian Queen Charlotte beach gold placer deposits, or billions of years old like the Elliott Lake uranium paleoplacer within the Huronian Supergroup in Canada.
The containing material in an alluvial placer mine may be too loose to safely mine by tunnelling, though it is possible where the ground is permanently frozen. Where water under pressure is available, it may be used to mine, move, and separate the precious material from the deposit, a method known as hydraulic mining, hydraulic sluicing or hydraulicking”.
So if you are going to mine gold and diamonds in Venezuela using the method described here you are almost guaranteed to achieve favorable results.

Major gold discoveries occurred in the Guiana Highlands during the mid-1800s, and a very rough estimate of 30 million ounces of gold was recovered from this region, although records are certainly spotty.

This is hardly a safe place for a man to try and find his fortune. The town of El Callao is full of mining activity, but most of the miners are operating illegally to recover gold in the streams and rivers here, and it is a dangerous place to operate.

Gold is not the only treasure that can be found here. Apart from gold, Venezuela also produces other minerals, like bauxite, coal, manganese, aluminum, iron ore, diamonds, oil, etc.

Diamond mining is also very active in the same regions of southeastern Venezuela, and rich diamond placers can be mined concurrently with some of the gold placers.

The largest diamond discovery was made in Icabaru River and weighed 154 carats. The Paragua River and Quebrada Grande River are known to be major diamond-bearing rivers.

The Caroni River is perhaps the best-known river for diamond mining in Venezuela. Diamonds of both gem and commercial grade are found in the river channel itself, and in elevated floodplains of the river.