Yes, the Congo was an important flashpoint during the Cold War because of it's deposits of minerals & industrial diamonds. Both the US and the Soviet Union had an interest in maintaining access to these resources. Obviously, these interests were potentially threatened by Congolese independence.
Belgium was undeniably an oppressive taskmaster during most of her stewardship over the Congo. But by the time of independence that had changed. First of all, Belgium had decided to grant independence, but wanted to move slowly because, and this was clearly Belgium's own fault, there were so few natives with professional training. But, contrary to Kingsolver's assertion, Congo had one of the highest literacy rates in Africa, over 40%. In addition, industrial production was growing rapidly and the country has vast natural resources. The underlying conditions seemed to be favorable for a gradual transition to a successful independent nation.
Instead, the Congolese demanded immediate independence and Belgium acquiesced. Patrice Lumumba, who even those sympathetic to his cause concede was unbalanced, became the fledgling nation's first Prime Minister on June 30, 1960, and within five days native troops mutinied and began raping and slaughtering whites and natives alike. Belgium sent her own troops back in to try to restore order and Katanga province, under the Christian and pro-Western leader Moise Tshombe, declared its independence from the Congo. Lumumba immediately aligned himself with the Soviet Union.
The UN, under the notoriously anti-Western Dag Hammarskjold, intervened and sent in troops to prop up Lumumba & quell the uprising in Katanga. This intervention was the bloodiest episode in UN history as UN planes actually ran bombing missions in Katanga. The UN troops used in this exercise specifically excluded Western Bloc nations like America. Hammarskjold viewed the UN as a sort of third side in the Cold War; a secular, liberal, non-aligned alternative to East and West.
In the months that followed, President Joseph Kasavubu demanded that Lumumba step down but he refused. Troops under Joseph Mobutu staged a coup and shipped a badly beaten Lumumba to Katanga where he was murdered. (There is some evidence that the CIA wanted Lumumba assassinated, but internal Congolese politics beat them to the punch.) Tshombe eventually abandoned Katanga's drive for secession and became Prime Minister of the entire Congo before Mobutu drove him into exile.