A method to improve the quality of rock preparation for extraction with emulsion explosives in open-pit mines with high benches

Increasing the production capacity of open-pit and strip mines while ensuring the efficiency of the mining enterprise can be achieved through enhancing the quality of rock preparation prior to excavation. The use of emulsion explosives and the transition to the high-bench technology can reduce the cost of mining operations by optimizing the drilling and blasting parameters. The article reviews methods to improve the efficiency of rock preparation for extraction based on the applicable scientific and methodological principles and it proposes a method to regulate the density of emulsion explosives. Schemes are presented for calculation of drilling and blasting parameters when implementing technical measures aimed at improving the blasting quality through rock preparation for extraction in conditions of overburden and mining operations with bench height of 15 m and higher. Parameters of drilling and blasting operations on high benches are justified with differentiation of the charge density along the length of the blast hole by controlling the delivery of the gas-generating additive. A simulation has been performed and the results of pilot tests of the emulsion explosive charge density control at the Ural deposits are presented.

Low density optimization of emulsion explosive to improve blasting quality (MNK Max70)

PT Multi Nitrotama Kimia is a mining service company engaged in providing blasting services and the largest sales of explosives in Indonesia. PT Pamapersada Nusantara jobsite Kideco Jaya Agung is one of the customers of PT Multi Nitrotama Kimia in the blasting service business unit. On a far more optimal side, the development of commodity price conditions and operational needs is a common concern. From these conditions, one of the best target cost controls for blasting and fragmentation is to make adjustments and improvement to the quality and quantity of the use of bulk products. The high use of bulk products at the Kideco Jaya Agung Jobsite is a particular concern, especially for rocks that require a high powder factor value, thereby increasing blasting operation costs. From this condition, PT Multi Nitrotama Kimia strives to optimize the bottom value of density product emulsion MNK Max70 using chemical improvement from the previous 1.15 gr/cc to 1.05 gr/cc. This improvement has brought good results, where optimization in terms of using bulks product and blasting quality such as fragmentation and Velocity of Detonation (VOD) values are still in accordance with product standards.

Damage Characteristics of Polymer Plates under the Impact of the Near-Field and Contact Underwater Explosion

In order to study the damage characteristics of polymer plates under the impact of the underwater explosion, the underwater contact and near-field explosion tests of polymer plates were conducted using different explosive quantities. In this paper, eight polymer plates with the size of 500 mm × 500 mm × 60 mm were made, and eight groups of explosion tests were carried out by using the rock emulsion explosive and nonconductive detonators. The damage modes and spatial distribution characteristics of the polymer plate generated by the underwater contact and near-field explosion impact with different explosive quantities are compared and analyzed. In addition, the characteristics of the shock wave propagation in the plates are investigated. It can be observed that the main damage mode of polymer plate is overall damage under the contact underwater explosion. For the near-field explosion, the main damage mode changes to overall failure, and the damage of contact explosion to polymer plate is greater than that of underwater near-field explosion. The polymer plate can reduce and delay the shock wave effectively, but the effect decreases with the increase of explosive quantity in the underwater contact explosion.

Tests of Samples of Emulsion Explosive Senatel Magnum before and after Introduction of the Marking Composition for Explosive Properties and Safety Criteria

The article is devoted to testing samples of the emulsion explosive Senatel Magnum before and after the introduction of the marking composition for explosive properties and safety criteria. It was established that the mixture of marking substances, which was introduced into the composition of the emulsion explosive Senatel Magnum, does not affect its explosive properties, as well as its safety in use during operation and conduct of blasting operations, since no inconsistencies were detected during tests by the specialists of explosive materials testing laboratory of the Expert Certification Center of Explosive Materials LLP. Various dyes were selected as marking agents. This choice is due to the fact that the dyes have a relatively low price, are very common on sale, when mixed with other substances, in particular industrial explosives, are determined visually. The technology was tested related to the introduction of marking additives into the compositions of multicomponent explosives without disrupting the technological process of their manufacture. Laboratory and field studies were carried out concerning safety criteria for explosives containing a marking composition. Thus, the urgent task is to ensure the possibility of marking (tagging) industrial explosives at the stage of their production with hidden marking additives, which will allow the product itself to be identified with the help of technical means — as an explosive, and to establish the brand of the detected explosive, manufacturer, and other required information.

INFLUENCE OF THE TYPE OF DONOR CHARGES ON THE DETONATION RATE OF LOW-SENSITIVITY EXPLOSIVES

The article discusses the creation, testing and implementation of new donor charges designed to initiate low-sensitivity explosives. The cast booster donor charges are made entirely of explosives obtained from the disposal of unnecessary ammunition – TNT, RDX and TEN. The donor charges differ from the mass-produced ones, and have a mass of 150 to 900 g. They also have high explosive characteristics: velocity of detonation from 7200 to 7500 m/s, density of 1.6 g/cm3, excellent water resistance and strength. Their initiating ability on low-sensitivity explosives is significantly better than the one of TNT presses. The velocity of detonation of the main charge of a low-sensitivity emulsion explosive initiated with a cast booster is up to 700 m/s higher than when initiated with a TNT presses. It is especially important when building objects in the constrained conditions, at development of mountain territories for decrease in action of shock air waves and elimination of possibility of mountain collapses and landslides In article advantage of use of cast intermediate detonators on safety of explosive works is proved at development of mountain territories. The new design allows an increase in the security of initiating the charges in the boreholes, which allows them to be initiated with two detonators simultaneously.

Full-scale tests and application of NPGM emulsion explosive at ALROSA

ALROSA performs blasting operations mainly using explosives manufactured on the spot. Considering modern trends of using local manufacture explosives, Company’s experience of application of emulsion explosives, as well as prompt introduction of technological innovations, novel process solutions are utilized in manufacture and use of emulsion explosives. To this effect, Udachny Mining and Processing Plant constructed and commissioned a plant to manufacture non-explosive components for emulsion explosives within the Plant’s infrastructure area. Emulsion explosives enable blasting in open pit and underground mines which are assumed hazardous in terms of oil and gas shows. Within the framework of technical upgrading at MMLT-500-PR Plant, the investment project on construction and commissioning of a modular production line to manufacture packaged emulsion explosives has been implemented. The field trials of NPGM grade emulsion explosive has proved the economic and production efficiency of blasting using this explosive in open pit and underground mining. This article presents the results of testing and application of NPGM emulsion explosive during blasting in open pit and underground mines of ALROSA. The outcomes of pilot explosions using this type explosive as the main borehole and chain charges, as well as intermediate detonators in full-scale conditions of an underground mine and in an open pit are described. The proposed technology features higher operational efficiency and is applicable in various geotechnical conditions of mineral mining.

Substantiation of parameters of mine working drivage with blasting technique and cleaning charges in advance cutting holes

Drilling and blasting operations (D&B) are the most difficult and laborious operations in the process of mineral extraction, requiring permanent development and upgrading of methods and equipment. The aim of the study is to substantiate the parameters of drilling and blasting drivage of horizontal and inclined (up to 12o) mine workings on the basis of high-performance self-propelled equipment and new designs of box cuts with cleaning explosive charges (0.2 kg of 6ZhV ammonite), placed in advance holes of 65 to 105 mm in diameter. The paper presents the results of the analysis of practical experience and scientific achievements in the field of drilling-andblasting rupture of solid media and continuum mechanics. The need for new designs of box cuts, reliability of which in the formation of high-quality (clean) cut cavity reaches 0.95-1.00, was substantiated. New design options of box cuts have been developed, the peculiarity of which consists in provision of sufficient compensation (peripheral) volume with the use of blast hole cut charges for blasting rupture of trapezoidal partitions, with the compensation volume factor of 2.50 to 1.34. Promising areas of research were shown using the example of complicated structure ore deposits and large faults in the Kirovograd ore district and crystalline rocks of the Ukrainian shield at the following mines of Ukraine: PJSC KZhRK, CJSC Sukhaya Balka (Kryvyi Rih), Vostok-Ruda LLC, SE VostGOK (Zheltye Vody), CJSC ZZhRK, etc. Promising areas of research were proposed using the example of complicated structure ore deposits typically formed at the junction of large faults; besides, the use of environmentally friendly emulsion explosives and self-propelled emulsion explosive chargers was recommended.