When the US Congress got together on Thursday (20) to discuss the environmental impact of cryptocurrencies, highlighted a growing problem for bitcoin (BTC) miners : the perception, whether fair or not, that they are a threat to the planet. One company that followed the meeting closely is Foundry , a subsidiary of the Digital Currency Group (or DCG ), whose network of bitcoin mining machines has become one of the two largest in the world, alongside China’s Antpool. The volume varies weekly. Foundry is a US success story as it helps its clients make thousands in bitcoins and helps repatriate…