The Virginia-based mining company reported that net income fell to $10.8 million, or 9 cents per share, in the last three months of 2010 from $18 million, or 15 cents per share, in the year-ago period.
Excluding expenses related to its Foundation acquisition and other items, Alpha said it earned 27 cents per share. Analysts surveyed by FactSet expected earnings of 55 cents a share.
Quarterly revenue increased 11 percent to $993 million. Analysts expected $1.01 billion.
Last month, Alpha announced another deal, agreeing to buy Massey Energy for $7.1 billion.
For the full year, Alpha said its net income rose to $95.6 million, or 79 cents per share, compared with $58 million, or 63 cents per share, in 2009. Annual revenue increased 57 percent to $3.9 billion.
Alpha said it expects to ship between 13 and 14.5 million tons of metallurgical coal this year, a company record. Metallurgical coal is used in steelmaking.
"In light of the devastating flooding recently experienced in Australia, spot prices for coking coal have risen," said Kevin Crutchfield, Alpha's chief executive officer. "Tight overseas market conditions are expected to persist throughout the year."
Shares fell 64 cents, or 1.2 percent, to $53.45 in pre-market trading.