Tau..

If they drill a series of holes 50 meters apart over a certain area that would be "Defining" the deposit..

If they get better readings in one area they would want better definition of the deposit so they would start drilling ,say 25 meters apart from the existing holes,but inside the original pattern..

That is called "Infill" drilling..

Step out holes would be if they found great globes of AU in one section of the original drill holes,they would then "Step out" ,drill outside of the original pattern in the direction of the Gloopy great gobs of AU..to find out how big the deposit..and they would keep stepping out in the same direction until they quit hitting the goodies..that way they can tell how big the deposit is and what direction the good stuff is,how deep,and all the rest including grades..

They would then go back and infill drill between the step out holes..

The infill drilling would be required to define the deposit grade for the 43-101 report.

Portee