In 2023, the M23 rebel group (which has been accused of receiving support from Rwanda, including weapons and logistical aid) in the eastern Democratic Republic of the Congo took control of the Rubaya coltan mine – one of the most important sources of tantalum globally – and began extracting and taxing the mineral to fund their operations. According to The Wall Street Journal, the group earns as much as US$300,000 a month by extorting money from miners and transporters. The coltan is then smuggled across the border into Rwanda, where it is laundered into the legal supply chain by falsely certifying it as Rwandan origin and “conflict-free.” This practice of coltan smuggling is well documented – for example, in one incident in March 2021, a truck crossing the border from the Democratic Republic of the Congo to Rwanda was found to be carrying 24 sacks of smuggled coltan.