Nighthawk Energy slipped back Friday after the US-focused oil group said it has conditionally raised £22.4m from a placing at 35p a share.It will use the money to undertake a 12 month development programme, including drilling 20 wells and building production facilities at the Jolly Ranch prospect in Colorado.There'll also be enough to spend on over 200 wells and the building of production facilities at the Revere project and cover corporate overheads.Earlier this week, AIM-listed Nighthawk said an independent valuation estimated oil in place at its Jolly and Craig Ranch fields to be 1.462 billion barrels gross. Nighthawk has a 50% stake in the fields, part of the Jolly Ranch project in Lincoln County. It bagged $10.9m last month from the sale of a 10% working interest in Jolly Ranch to Swiss finance group San Severina. Partner Running Foxes also sold a 10% stake.Nighthawk gets a further $29m if San Severina exercises options to increase its interest by another 20%, half from each of Jolly Ranches owners.It will get another $5m from the sale of a 50% interest in the Centurion project to Osceola Hydrocarbons.