I just finished the book China Safari. It's a little dated (2006), but it was still a good read. Basically, China is investing in Africa for the long haul.

Things I thought were interesting from the book:

There are sizable Chinese communities in Africa with the largest being in South Africa (~300,000). The Chinese don't intermarry or socialize much with the Africans because "The don't like them".

“What do you call it again, that thing of yours where everyone decides and nothing works?” “Um . . . you mean democracy?” “Yeah, that’s it. We don’t need it in China, and we don’t need it in Africa.” —Conversation with businessman Roy Zhang.

"A whole family in China will save for years to send one member to Africa, where the demand for services and goods is great and competition weak."

“I’m going to be honest with you. China is using Africa to get where the United States is now, and to surpass it. It is willing to do anything to achieve that, even build a Nigerian railroad that has no hope of making money [an $8.3-billion contract signed in November 2006] or launch a Nigerian satellite into orbit”—mission accomplished May 14, 2007.

“The Congolese often tell us it would have been better had China colonized the country, rather than France. The French have done nothing for this country—no roads, no factories, nothing. If the Chinese had come here earlier, the beach would be covered by skyscrapers.”

"The Chinese feel they have been sent on a mission. For them, doing business here is some form of conquest; their mission is to become the most powerful nation on earth, as they were a thousand years ago."

"They see Africa as a virgin space, abandoned by the West, and in need of a new conqueror.”

"China has military agreements with forty-three African countries, and between 2001 and 2006, leaders of the Chinese army went to Africa thirty times."

"Gulf of Guinea. Those in the know consider this to be one of the most promising areas of exploration in the world, one that could replace the Persian Gulf and that might one day account for a quarter of all American imports."

“The fact that we [US] favor humanitarian aid over economic opportunity is seen by Africans as a sign that we still don’t take them seriously. We continue to act arrogantly, using aid as a way of controlling Africa. This is a strategy that no longer works now that we’re not the only ones active there."

"Looking to the future, if nothing checks China’s momentum, its infrastructure work alone will help unify the continent. There will be a coast-to-coast railroad, electricity and water networks, oil pipelines running across national borders, and even freedom to travel between nations for the Africans."

Looking for more recent stats I found thisI found this:

Once a largely neglected region of the world, sub-Saharan Africa has quietly become the center of a struggle for influence between what are arguably the world’s chief powers: China and the United States.

There is no overstating the stakes, given the abundant natural resources Africa has to sustain the needs of growing economies throughout the world, including metals like bauxite, used for its aluminum; platinum, used in catalytic converters, lab equipment and dentistry tools; and nickel, used in batteries, magnets and stainless steel.
....

To his credit, President Barack Obama has taken some steps to rectify this imbalance. On the eve of the U.S.-Africa Leaders Summit in Washington last August, for example, Obama announced that U.S. companies had committed to invest $14 billion in Africa. But that is a mere pittance when compared to an estimated $75 billion in investments China has made in Africa from 2000 to 2011.