The trucking and oilfield services company said it earned $27.4 million or 30 cents per share on $310.3 million in revenue for the quarter ended June 30.
That compared with a profit of $7.4 million or nine cents per share on $320.1 million in revenue a year ago.
Excluding the impact of foreign exchange and change in the fair value of investments, Mullen said it earned an adjusted profit of $20.9 million or 23 cents per share, up from $18.5 million or 23 cents per share a year ago.
The company attributed the drop in revenue in large part to an $8-million hit due to the completion of a thin fine tailings barge system project for an oilsands customer last year.
Excluding the barge project, Mullen Group said revenue from its core business slipped just $1.8 million from a year ago.
"In terms of revenue from our core business, we were down marginally due to the decrease in demand for our services tied to drilling activity that experienced a slow down in Western Canada, which in part was the result of unfavourable weather conditions," president and co-chief executive Stephen Lockwood said in a statement.
"Also of note is the improvement of our earnings per share in the second quarter that was positively impacted by gains made in our strategic investments."
Mullen Group provides trucking and other services to the oil and natural gas industry in Western Canada.