We approached Carlos Lara, Manager of the Mineral Processing Department of Grupo Peñoles’ Center of Investigation and Technological Research. Grupo Peñoles is the world’s biggest refined silver producer and Latin America’s leader in refined gold and lead production, so we considered this meeting of the utmost importance. We wanted to see if our project’s design was actually suited for the metal recovery from e-waste. In addition, we wanted to know if we could use our technology to improve the current methods where metals are recovered from mines and make them less damaging to the environment.

Carlos Lara agreed to share his experience with us, which he has plenty of thanks to his 45-year career at Grupo Peñoles. He gave us valuable insights on the mining industry and metal recovery in Mexico, which helped us immensely and inspired us to modify our initial project.

Mr. Lara explained that there was an attempt here in Mexico to implement bioleaching as a way to recover metals from mines, based on previous experiences reported in mines in Chile. However, this project failed because they didn’t take into account the difference in composition of the Chilean and Mexican ores. Chilean ores are mainly composed of copper, which is perfectly suited for the metal recovery using our initial microorganism: A. ferrooxidans, but when they tried to implement this same process, they realized that it wasn’t profitable here in Mexico because Mexican ores have much higher concentrations of silver.

This real-life experience and the fact that after collecting all the disposed electronic devices you can recover a considerable amount of gold and silver made us reconsider our project and add a new bioprocessing step with another microorganism capable of recovering silver and gold: C. violaceum. Even though during our previous research for project ideas we found that C. violaceum could be used to recover precious metals from e-waste, at first we weren't considering to include it in our process. However, after our interview with Mr. Lara it was clear that we had to integrate C. violaceum into our process. This way we would not only be reducing pollution by recycling precious metals from an already used source, but we would also be able to propose our process as a suitable, profitable and more environmentally friendly way to recover metals from natural ores in Mexico.