Original title: Estimation of output and unit cost of down-the-hole drill! Hengwang Group 1． Main factors for selection of down-the-hole drill -Production capacity ─ Total unit cost Total cost = total machine price + operating cost Cost per hour = cost of ownership per hour (depreciation + interest) + operating cost per hour Cost of ownership per hour + cost of operation per hour Total cost/m3 = Output per hour (m3) The main purpose of reducing the total unit cost -- Lower cost of ownership (buy a lower-priced DTH rig) -- Can reduce operating costs (buy reliable and simple to maintain and small and fuel-efficient down-the-hole drills) -Can increase production (buy high efficiency automatic large down-the-hole drill) 2． Main factors for calculating the production capacity of down-the-hole drill ─ Diameter of down-the-hole drill -hole depth (or working face height) ─ ─ Unit drug consumption (P. Ｅ．） Total weight of explosive in borehole W Expand the full text = ────────────── = ────── Step height × hole spacing × row spacing H × S × B ─ ─ Type of explosive (specific gravity of explosive) ─ ─ Average production rate of penetration The rate of penetration varies depending on the rock, the down-the-hole drill,Borehole Drill Bits, the air pressure and the flow rate, and the average rate of penetration is usually between 0.4 and 0.5 of the net rate of penetration of the down-the-hole drill,dth hammer bit, depending on the efficiency of the operator, the efficiency and speed of pulling out, mining dth bit ,dhd drill bit, changing the rod and shifting the down-the- hole drill. ─ ─ Hole pitch and row pitch The hole spacing and row spacing can be calculated according to the factors such as hole diameter, step height, overdrilling, plugging, unit explosive consumption and specific gravity of explosive, and then confirmed on site. 3． Estimation of total unit cost of down-the-hole drill Dth cost estimates fall into three broad categories １. Operating costs ─ ─ Wages of chief and assistant operators ─ Fuel consumption cost ─ ─ Lubricating oil cost of drilling tool ─ Maintenance cost ─ ─ Parts cost ２. Drilling tool consumption cost -Drill bit (base price and life) -Drill pipe (also depends on base price and life) ３. Cost of ownership -Total price of down-the-hole drill ─ ─ Working time of down-the-hole drill per year (hours) ─ ─ Depreciation period -- Interest -The remaining price of the old machine after a few years. ※ The cost of ownership per hour can be calculated by the following equation ＰV－［ＲＶ×（１＋i）-N ］ ＰＭＴ＝──────────────── １－（１＋i）-N ［──────────］ ｉ Where PMT = cost of ownership per hour PV = total price of down-the-hole drill N = Hours worked per year I = Interest RV = residual price of used machine ※ Available as a rough estimate Cost of ownership per hour = depreciation cost per hour + interest cost per hour Machine price Hourly depreciation cost = Year × working hours per year Machine price × annual interest/2 Interest cost per hour = Hours worked per year 4． Simplicity: The output of the down-the-hole drill mainly depends on the diameter of the drill hole and the production drilling speed. Ownership cost is only 15% to 20% of the total unit cost, and operating cost is the main cost. ─ ─ The efficiency, production capacity and operational rate of the down-the-hole drill directly affect the total unit cost, which are the main factors to be considered when selecting the down-the-hole drill. Reprinted from the network,dth button bits, the copyright belongs to the original author, if there is infringement, please contact to delete! Read this article with. Return to Sohu to see more Responsible Editor:. wt-dthtools.com
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