The great bulk of the uranium used in both the American and German atomic bomb programs during World War II came from the Shinkolobwe mine in the Belgian Congo, which had been closed down by the start of the war. Germany had access to the uranium inventory in Belgium after invading that country in 1940, and the U.S. made arrangements with Belgian Congo officials to purchase the ore and tailings remaining at the mine and subsequently made arrangements to have the mine reopened to provide uranium for the Cold War atomic weapons program.
During and immediately after World War II there were only a few known uranium deposits (western U.S., Canada, Czeckoslovakia), and the concentration of U3O8 in the ore was very low, significantly less than 1%. At Shinkolobwe, on the other hand, the concentration in the ore was as high as 70%, and even the concentration in the tailings was 20%. For this reason, it was important for the U.S. to obtain its output and to prevent Germany from doing so. Acquiring the output required negotiations with Union Minière officials in the Belgian Congo, which officially had sided with the Allies, but preventing the smuggling of uranium to Germany required the use of spies from the Office of Strategic Services (OSS), the forerunner to the Central Intelligence Agency (CIA). The focus of this book is the activities of these spies.
The challenges the OSS agents faced were daunting. While the governor general of the Belgian Congo had sided with the allies, there were many officials who, feeling that Germany was likely to win the war, were in favor of neutrality such that they could trade with both the Axis and the Allies, thereby profiting no matter what happened. To the north of the Congo was French Central Africa. Like Belgium, France was occupied by the Germans. This French colony had chosen to be loyal to the government in exile under Charles de Gaulle but was still a hotbed of spy activity and smuggling. To the southwest was the Portuguese colony of Angola. Portugal was officially neutral but was under the control of a fascist dictatorship sympathetic to Germany. Hence, Angola was an ideal route for smuggling uranium and other resources such as industrial diamonds out of the Belgian Congo. There were also enemy agents playing for keeps. After a contact accidentally blew his cover, one OSS agent survived three attempts on his life before returning to the U.S. Aside from these issues, the OSS agents frequently suffered from tropical diseases and had to deal with language barriers given the numerous languages spoken in the Belgian Congo and the surrounding territories.
One aspect of the book that I really appreciated was Dr. Williams commitment to readability. At the front of the book is a list of the key individuals with their roles as well as code names if they were OSS. Next to it was a list of acronyms. Furthermore, she would use organization names and their acronyms interchangeably in the following manner. She would first use the proper name and then use the acronym. If there was a gap of a chapter or more before needing to use the acronym again, she would re-introduce the proper name before reverting to the acronym. With the alphabet soup of acronyms and the numerous individuals involved, these features made the book easier to read.
I have one technical criticism. In the book, Dr. Williams states that the higher uranium concentration in the Shinkolobwe ore reduced or eliminated the need to enrich the uranium. In this, she was mistaken. Of the naturally occurring isotopes of uranium, one, U-235 is capable of fission, and it comprises approximately 0.7% of natural uranium, regardless of the concentration of the uranium in the ore. The uranium in the atomic bomb dropped on Hiroshima required a U-235 content of greater than 90% for the bomb to work. The process of raising the U-235 concentration is known as enrichment, and that took place at the gaseous diffusion plant at K-25 and the calutrons at Y-12, with both facilities located at Oak Ridge, TN.
In spite of occasionally having to discuss the availability of some source material or admit uncertainty about what happened or how something happened, Dr. Williams managed to keep the book reading like a thriller. As a result, I enjoyed the book and had trouble putting it down.