Method and apparatus for controlling the operation of cluster drill of down-the-hole hammers

An apparatus for drilling hole, comprising:

• a cluster drill of down-the-hole (DTH) percussion hammers, the cluster drill of DTH percussion hammers comprising two or more DTH percussion hammers each equipped with a drill bit;
• a special distributor for distributing compressed air or pressurized fluid from two or more independent supply sources to the cluster drill of DTH percussion hammers, the special distributor being connected to the cluster drill of DTH percussion hammers;
• and
• a rotary head for providing rotational turning speed and output torque for the apparatus, the rotary head being connected to the special distributor;
• wherein each of the DTH percussion hammers is supplied with the compressed air or pressurized fluid from one of the two or more independent supply sources;
• wherein not all of the DTH percussion hammers are supplied with the compressed air or pressurized fluid from the same independent supply source;
• and
• wherein the apparatus being further characterized in that the cluster drill of DTH percussion hammers is adapted to drill in both homogenous and mixed ground formations, such that when one or more of the DTH percussion hammers are impacting soft ground and causing direct exhaustion of the compressed air or pressurized fluid supplying the particular one or more of the DTH percussion hammers, the rest of the DTH percussion hammers continue being pressurized and hammering.