RMZ – MATERIALI IN GEOOKOLJE

у 3 b400 D = f eShemetov, P. A., Bibik, I. P.К3fKecharge relative to locking charge withplacing the latter in the main blastholewas maintained by various length ofshock-wave tubes (SWT) for lowerand upper boosters with their concurrentinitiating by dentonator of surfacenetwork and was about 7 ms at 2000m/s detonation speed in SWT. In orderto delay the primary charge relative tolocking charge in aditional blasthole acombination of retardants rating (25,42 and 67) ms in surface network wasused. As a result, an interval betweenexplosion of the primary charge andlocking charge was between 17–25ms. It has been established that applicationof locking charge in additionalblasthole has increased extent of rocksolid breaking by 8–10 % and reducedspecific BE consumption by 3 %.Application of emulsion explosiveformulations (EEF) with controlledvolume concentration of explosionenergy applicable for charging dryand watered blastholes, together withcombined structure of charges makes itpossible to meet in practice any technologicalchallenges of DBO owing toavailable park of drilling rigs. This circumstancepromotes increasing heightof benches that allows of reducingquantity and length of transport horizons,increasing open pit wall slope,enhancing intensity of mining in deepopen pits. Moreover, engineering andeconomical performance of open pitmining is increasing.D =K f=HуCtgα+ CbHКCtgαK+ C55,A procedure of high bench blasting has4been developed, 55K which main point consistin 4the 0.1 following. σ Rocks are brokenf=0.1σcom ,comby Q a pair of divergent blasthole charges.VSpecifically, = one blasthole in each pairis KBEQVdrilled 0 = K perpendicularly to bench toe,BEand QV0 the second one – towards benchslope ∆with incline to the toe. Verticalaand K∆= inclined blastholes are arrangedain K parallel =∆r∆vertical planes spaced apartby distance ∆r equal to 1–2 diameters ofblasthole Qequivalent in terms of chargeenergyad =to total, mQ charge in a pair of divergentad =qHblastholes.у , m Blasthole angle andlimit benchqHу height are determined bythe following formulas:1.13Hqβ = arctg ,deg ree;1.13 d H qβ = arctgeγ,deg ree;deγ(11)π ⋅γ2de− 2cπq⋅γН = 2de− 2c, m2 ⋅ ctg q αН =, mwhere α,2β⋅–ctganglesαof bench slope andinclination of bast blastholes bastσin cluster; Нtσt– D дbench = D0 height; 2 bast d e−– 2diameter bast + of 1chargehrequivalent = 2in terms throf 2 charge tD energy 1 toдDσt0−σt +hrhrtotal charge in σt a cluster σof t blastholes;q – specificnBE consumption; γ – densityof ∑ncharging lопi BE in a blasthole; c –i=1lsafety ∑berm.lд= оп − ( 1.5...5. 0) diadholeдi=1lд=n− ( 1.5...5. 0) dadholeдEffectiveness n of the developed procedureof high bench blasting hasbeen tested experimentally during reactivationof western wall of Muruntauopen pit mine. An area of the pitRMZ-M&G 2012, 59