Sys­tem So­lu­tions for Min­ing and Tun­nelling in Small Sized Tun­nels

NBM&CW - - EQUIPMENT & MACHINERY -

Mine op­er­a­tors are now in­creas­ingly call­ing for machines that are mo­bile, highly ma­noeu­vrable, and ca­pa­ble of un­der­tak­ing a wide range of road­way and tun­nel dri­vage and re­con­struc­tion works.

When choos­ing a par­tic­u­lar ma­chine type, its de­gree of mech­a­ni­sa­tion has to be weighed up against the mul­ti­pur­pose na­ture of the de­ploy­ment, which will then de­pend on the type of ap­pli­ca­tion and op­er­at­ing en­vi­ron­ment. While a “sim­ple” all-hy­draulic con­trol sys­tem will not fea­ture all the avail­able sen­sor technology, and will have cer­tain lim­i­ta­tions when it comes to the au­to­ma­tion of in­di­vid­ual pro­ce­dures, when com­pared to an all-au­to­matic ma­chine, it will be more ro­bust un­der cer­tain op­er­at­ing con­di­tions, will re­quire less main­te­nance ef­fort, and will en­tail lower pro­cure­ment costs.

Many man­u­fac­tur­ers in India can sup­ply crawler-mounted base ve­hi­cles in a num­ber of weight cat­e­gories, which can be equipped with dif­fer­ent drive units, and can be sup­plied with or with­out quick- re­lease at­tach­ments. The range of an­cil­lary equip­ment avail­able in­cludes work­ing plat­forms, drill feed, side-tip­ping shov­els, and ac­ti­vated dint­ing shov­els and spe­cial so­lu­tions such as cut­ting heads with air­wa­ter ex­ter­nal spray sys­tems and spe­cial shov­els for lay­ing curb stones.

Con­ven­tional equip­ment pro­file tun­nelling for small-

Ex­ca­vat­ing small road­way and tun­nel pro­files us­ing drilling and blast­ing meth­ods, tra­di­tion­ally re­quired ma­noeu­vring hitches to be pro­vided in the side-walls for ma­te­ri­als trans­port, and to al­low the dif­fer­ent ve­hi­cles and items of equip­ment to pass each other, or be parked-ready for op­er­a­tion, as each process in the road head­ing cy­cle gen­er­ally calls for a dif­fer­ent ma­chine with its own run­ning gear. This means pro­vid­ing a large fleet of ve­hi­cles, re­sult­ing in high pro­cure­ment and op­er­at­ing costs. Ma­noeu­vring the in­di­vid­ual machines into place takes time and fur­ther de­lays the se­quence of op­er­a­tions.

Mul­ti­func­tion machines like the HBL 800 drill-loader (Fig1) have the po­ten­tial to in­crease the rate of ad­vance in that the main op­er­a­tions in the road head­ing cy­cle, namely drilling and load­ing, are com­bined in one car­rier ve­hi­cle. This mul­ti­pur­pose ma­chine is de­signed to op­er­ate on its own at the head­ing face. A drill feed at­tach­ment is fit­ted for shot hole drilling and roof bolt­ing work (Fig 1), this be­ing re­placed by a side­tip­ping shovel (Fig­ure 2) for the load­ing cy­cle. There is also the op­tion of con­nect­ing a shot-crete ma­nip­u­la­tor. The in­stal­la­tion is de­signed to op­er­ate in arch-pro­file tun­nels with cross sec­tions of 10 m2 and over. A twoto-one turnout and a pre­assem­bled sec­tion of track are also in­te­grated into the sys­tem to serve as a floor-rail trans­port route. Other avail­able at­tach­ments in­clude tele­scopic drill feeds, a range of dint­ing shov­els, hy­draulic ham­mer drills, and var­i­ous spe­cialised tools for car­ry­ing out tun­nel sta­bil­i­sa­tion work.

The HBL 800 drill-loader is equipped with elec­tro-hy­draulic drive and is op­er­ated from a driver’s cab with an over­head canopy to pro­tect against fall­ing stone. Us­ing the ma­chine as a stand-alone mul­ti­func­tion sys­tem for road head op­er­a­tions places higher stresses on the base ve­hi­cle when it comes to han­dling and ser­vic­ing. How­ever, pro­cure­ment and op­er­at­ing costs are lower than for con­ven­tional ma­chine sys­tems, which com­prise a drill jumbo and loader, as only the ba­sic ma­chine has to be pur­chased and ser­viced. Any main­te­nance work needed can be car­ried out dur­ing non-

Fig­ure 1: HBL in po­si­tion ready for drilling

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