Design a $($from $1$st principles$)$ drilling, charging and timing round for a rectangular tunnel with the following dimensions: Height $3\mathrm{.}3$m$,$ width $3\mathrm{.}7$m in a friable quartzite. Do not make use of a computer model. The proposed hole diameter is $48$mm$.$ Final drill hole length is $3\mathrm{.}3$m on a mechanised drill. Select:

$1.$ an ANFO explosives type in your first proposed design and

$2.$ bulk emulsion type explosives for the second design.

You may select your own initiation system$/$s for the $2$ different designs. Compare the drilling and blasting cost per m$3$ between the ANFO design and the bulk emulsion design.

Assume a drilling cost of R$44\mathrm{.}50$ per metre. ANFO $=>$ R$13\mathrm{.}00/$kg$,$ Emulsion $=>$ R$14\mathrm{.}75/$kg$,$ In$-$hole detonator $=>$ R$42\mathrm{.}50/$unit and tamping cartridges $=>$ R $2\mathrm{.}30/$unit$.$

The average advance per blast is $3\mathrm{.}1$m for the ANFO blast and $3\mathrm{.}2$m for the emulsion blast.

Do you agree with the advances? Clearly show all the assumptions you are making.

Complete the table below and discuss the costs. $($Plan design is to the full drill depth and the actual is to the full drill depth minus the socket remaining after the bl Question $1$: $,(50$ marks$)$

Design a $($from $1^{st}$ principles$)$ drilling, charging and timing round for a rectangular tunnel with the

following dimensions: Height $-3\mathrm{.}3$ m $,$ width $-3\mathrm{.}7$ m in a friable quartzite. Do not make use of a

computer model.

The proposed hole diameter is $48$ mm $.$ Final drill hole length is $3\mathrm{.}3$ m on a mechanised drill. Select:

an ANFO explosives type in your first proposed design and

bulk emulsion type explosives for the second design.

You may select your own initiation system$/$s for the $2$ different designs. Compare the drilling and

blasting cost per $m^3$ between the ANFO design and the bulk emulsion design.

Assume a drilling cost of R$44\mathrm{.}50$ per metre. ANFO $=>$ R$13\mathrm{.}00/$kg$,$ Emulsion $=>$ R$14\mathrm{.}75/$kg$,$ In$-$hole

detonator $=>>$ R$42\mathrm{.}50/$unit and tamping cartridges $=>$ R $2\mathrm{.}30/$unit$.$

The average advance per blast is $3\mathrm{.}1$ m for the ANFO blast and $3\mathrm{.}2$ m for the emulsion blast.

Do you agree with the advances? Clearly show all the assumptions you are making.

Complete the table below and discuss the costs. $($Plan design is to the full drill depth and the actual is

to the full drill depth minus the socket remaining after the blast$)$

Costs per metre $=$ costs per metre advance. Complete the table below and discuss the costs. $($Plan design is to the full drill depth and the actual is to the full drill depth minus the socket remaining after the blast$)$

Costs per metre $=$ costs per metre advance.

$\backslash$table$[[,$ANFO Design,Emulsion Design$],[,$Plan,Actual,Plan,Actual$],[,,,,],[$Drilling cost $/$ metre,,,,$],[$Initiation cost $/$ metre,,,,$],[$Explosive cost $/$ metre,,,,$],[$Total cost $/$ metre,,,,$],[$Drilling cost $/$ m$3,,,,],[$Initiation cost per m$3,,,,],[$Explosive cost $/$ m$3,,,,],[$Total cost $/$ m$3,,,,]]$