It began before Maduro. Under Hugo Chavez then President of Venezuela confiscated Junior gold explorerer Krystallex Gold asset. Google it. In 2011 it was ready to start production.

Also Chavez ordered country gold 200 tons stored in NY to be delivered to them.

When investing in mining company country matters.

How a country goes corrupt : “it took time for them to have their people in place,” Sound familiar like in US now.

Miami Herald article: Pillaging El Dorado: Here is how Maduro and his cronies siphon out Venezuela’s gold

“When they first arrived, they found that the oil industry was totally mechanized, controlled by rules and accountability instruments that they would have to evade. That created hurdles for stealing the wealth and it took time for them to have their people in place, and it was after a long process that they could start pillaging,” the officer who spoke under condition of anonymity said.

“But with gold the situation is different, because with gold there is no supervision. If the complex processes one thousand kilograms of gold, nobody is there to audit it. And they distribute the loot among themselves,” he added.”

https://www.miamiherald.com/news/nation-world/world/americas/venezuela/article236664243.html