Apollo Micro Systems Ltd (AMSL) shares surged over 4 percent, reaching an upper circuit of 5 percent, following an announcement that its subsidiary, IDL Explosives Ltd, secured a significant running contract. The contract, valued at approximately Rs 421 crore, is for supplying bulk explosives to Coal India Ltd subsidiaries. Additionally, the subsidiary received an export order for cartridge explosives, bringing the total order value to around Rs 420.9 crore.