Highly improved drilling machines and mucking machines have been used for the underground construction. To have rapid construction, particularly, it is important to shorten the cycle time of blasting operation. At the most tunneling in the present, cartridged emulsion explosives have mostly been used for tunnel blasting in Japan. At the present day, a blasting system of ANFO using a loading machine has been introduced recently for a tunnel blasting. However, ANFO has some problems, such as a useless explosive in wet boreholes, bad blasting fume and producing the ammonia gas due to the decomposition of ammonium nitrate in contact with the sprayed concrete in tunnel.
A blasting system using bulk emulsion explosives with loading machine has been used practically in the world. However, it is difficult to introduce this system to Japanese tunneling because of the Japanese Explosives Control Law. Also, bulk emulsion explosives need complicated loading machine for chemical gassing. Therefore, we, Nippon Kayaku Co., Ltd has developed granular emulsion explosives with the development concept, which has explosive properties of emulsion explosives and handling property similar to ANFO. And the field blasting tests were carried out to confirm actual operations and blasting effects in some tunnels. As a result of the field tests, the loading time of explosives can be reduced. The cycle time of blasting operation is less than that of cartridged explosive products, and blasting fume are much better than that of ANFO.
トンネル掘進発破や砕石場のベンチ発破においては，爆薬装填作業の機械化の要望がある。この課題に対して，世界的には流動性をもつエマルション爆薬をモーノポンプ等で装薬するバルクエマルション爆薬が普及している。しかし，良好な爆轟性能，耐水性，後ガス等の長所を持つ反面，高粘性の物性であるために周囲への付着等のハンドリング面，また正確な火薬の数量管理が難しいといった短所がある。また，ANFO爆薬は簡便なエアーローダーでの装填は可能であるが，耐水性がなく様々な作業環境に対応できないといった問題がある。そこで，｢含水爆薬並みの威力，耐水性，後ガス，及びANFO爆薬並みの機械装填性，ハンドリング性を併せ持つ爆薬｣を開発コンセプトに，粒状エマルション爆薬を開発した。さらに，粒状エマルション爆薬の現場での実用評価試験を実施した結果，含水爆薬と比較し，孔数の削減及び装薬時間の短縮，また，ANFO爆薬と比較し，薬量の削減及び後ガスの良好性が確認できた。
Granular emulsion explosives, Loading machine, ANFO