+========================+=======+=======+=======+======+=======+======|
| | FEET OF HOLE | POUNDS OF POWDER |
| |DRILLED PER CUBIC YARD | USED PER CUBIC YARD |
| | OF EXCAVATION. | OF EXCAVATION. |
| +-------+-------+-------+------+-------+------|
|Portion of excavation. |15-ft. |19-ft. |24-ft. | | | |
| | 4-in. | 6-in. | 6-in. |15-ft.|19-ft. |24-ft.|
| |span-- |span-- |span-- |4-in. | 6-in. | 6-in.|
| | twin | twin | twin | | | |
| |tunnel.|tunnel.|tunnel.| | | |
|------------------------+-------+-------+-------+------+-------+------+
|Wall-plate heading[C] | 13.0 | 10.97 | 10.97 |3.77 | 2.85 | 2.85 |
| | | | | | | |
|Total heading[C] | 7.87 | 8.17 | 7.81 |2.31 | 2.02 | 1.78 |
| | | | | | | |
|Bench and raker bench[C]| 5.97 | 6.15 | 7.56 |0.94 | 0.93 | 1.13 |
| | | | | | | |
|Trench[C] | 9.82 | 15.96 | 18.10 |1.84 | 2.49 | 2.73 |
|------------------------+-------+-------+-------+------+-------+------+
|Average for section[C] | 6.69 | 7.43 | 8.95 |1.28 | 1.30 | 1.45 |
|------------------------+-------+-------+-------+------+-------+------|
|Actual amount[D] | 6.82 | 7.27 | 8.95 |1.22 | 1.24 | 1.27 |
+========================+=======+=======+=======+======+=======+======+
[C] Figures taken from typical cross-sections.
[D] This gives the actual amount of drilling done and powder used per
cubic yard for the whole period of 5 months of observation, but as this
length included 280 ft. of heading and only 220 ft. of bench, the
average figures (for powder especially) are too low.
Table 6 gives the rate and cost of drilling, and the cost of powder. It
will be seen that the average rate of drilling was 2.71 ft. per hour per
drill or 27.1 ft. per drill per shift.
Table 7 shows the result of observation as to the time taken in various
subdivisions of the drilling operations. These observations were not
carried on for a long enough period to give correct results, but the
percentages of time spent on each division of the operation are believed
to be about right. The headings of this table are self-explanatory. The
necessary delays include all time spent in changing bits, making
air-line connections, etc. The unnecessary delays are stoppages caused
by lack of supplies or insufficient air pressure.
By Table 6 it will be noticed that the cost of labor for drilling and
sharpening steels was about $0.29 per lin. ft. of hole drilled. The
total cost, including repairs, supply of air, etc., came to about $0.38,
as will be seen from Table 8.
_Timbering._--On the New York side nearly the whole length of the
excavation needed timbering, to a greater or less extent, and for the
most part required timbering of quite a heavy type.
TABLE 6.--ROCK TUNNEL EXCAVATION UNDER 32D STREET, EAST OF CUT-AND-COVER
SECTION. DRILLING AND BLASTING.--DETAILED COST OF LABOR IN DRILLING,
ALSO QUANTITY AND COST OF POWDER USED.
+=====================================================================+
| DRILLING AND BLASTING. |
|-----+-----+------+------+------+-----+-----+------+-----+-----+-----|
|Type.|Date.|Total feet drilled. | No. drill shifts| Feet drilled |
| | | | | | of (10-hour.) |per man per hour.|
| +-----+------+------+------+-----+-----+------+-----+-----+-----+
| |1907 |Head- |Bench |Total |Head-|Bench|Total |Head-|Bench|Total|
| | | ing | | | ing | | | ing | | |
|-----+-----+------+------+------+-----+-----+------+-----+-----+-----+
|_Ke._|May | 2,971| 5,578| 8,549| 98 | 204 | 302 |3.031|2.734|2.831|
| |June | 2,093| 6,194| 8,287| 85 | 223 | 308 |2.462|2.777|2.691|
| |July | | 7,627| 7,627| | 268 | 268 | |2.845|2.845|
| |Aug. | | 2,552| 2,552| | 95 | 95 | |2.688|2.688|
| |Sept.| | 2,133| 2,133| | 79 | 79 | |2.700|2.700|
| +-----+------+------+------+-----+-----+------+-----+-----+-----+
| |Total| 5,064|24,084|29,148| 183 | 869 |1,052 |2.767|2.77 |2.77 |
|-----+-----+------+------+------+-----+-----+------+-----+-----+-----+
|_Ki._|May | 6,976| | 6,976| 216 | | 216 |3.229| |3.229|
| |June | 4,089| | 4,089| 135 | | 135 |3.029| |3.029|
| |July | | 3,733| 3,733| | 140 | 140 | |2.666|2.666|
| |Aug. | | 6,715| 6,715| | 249 | 249 | |2.769|2.769|
| |Estim| |14,742|14,742| | 46 | 546 | |2.700|2.700|
| +-----+------+------+------+-----+-----+------+-----+-----+-----+
| |Total|11,065|25,190|36,255| 351 | 935|1,286 |3.152|2.694|2.819|
|-----+-----+------+------+------+-----+-----+------+-----+-----+-----+
|_Ko._|May | | 1,617| 1,617| | 55| 55 | |2.921|2.921|
| |June | | 2,948| 2,948| | 107| 107 | |2.755|2.755|
| |July | | 3,734| 3,734| | 131| 131 | |2.850|2.850|
| |Aug. | | 8,260| 8,260| | 290| 290 | |2.848|2.848|
| |Estim| | 4,787| 4,787| | 285| 285 | |1.180|1.680|
| +-----+------+------+------+-----+-----+------+-----+-----+-----+
| |Total| |21,346|21,346| | 868| 868 | |2.460|2.460|
|-----+-----+------+------+------+-----+-----+------+-----+-----+-----+
|Grand|Total|16,129|70,620|86,749| 534 |2,672|3,206 |3.020|2.710|2.710|
+=====+=====+======+======+======+=====+=====+======+=====+=====+=====+
+==================================================+=====================+
| DRILLING AND BLASTING | POWDER USED. |
|-----+----------+------+--------------------------+--------+-------+----+
| | | | Cost of labor only. | | | |
| | | | Drilling and sharpening. | | | |
| | | +------+------+-------+----+ | | |
| | | | | | Per | | | Cost | |
| | | | | | cubic | | | per | |
| | | | | | yard. | | | cubic | |
| | | | | | | | |yard at| |
| | | | | | | | | 11 | |
| | | | | | | | | cents | |
| | | | | | | | | per | |
| | | | | | | | |pound. | |
| +----------+------+------+------+-------+----+--------+-------+----+
|Type.| Quantity | |Total.| Per |Actual.|Paid| Total |Actual.|Paid|
| | of | | |linear| |for |Quantity| |for.|
| |excavation| | |feet. | | | | | |
| | in cubic | | | | | | | | |
| | yards. | | | | | | | | |
| +----------+------+------+------+-------+----+--------+-------+----+
| | Actual. | Paid | $ | $ | $ | |Pounds. | $ | $ |
| | [E] | for | | | | | | | |
| | | [F] | | | | | | | |
|-----+----------+------+------+------+-------+----+--------+-------+----+
|_Ke._| 1,736 | 1,664| 2,331| 0.27 | 1.34 |1.40| 1,595 | 0.10 |0.10|
| | 809 | 698| 2,440| 0.29 | 3.01 |3.49| 1,960 | 0.27 |0.31|
| | 1,022 | 960| 2,031| 0.26 | 1.98 |2.11| 966 | 0.10 |0.11|
| | 743 | 716| 640| 0.25 | 0.86 |0.89| 430 | 0.06 |0.07|
| | 238 | 238| 533| 0.25 | 2.24 |2.24| 280 | 0.13 |0.13|
| |----------+------+------+------+-------+----+--------+-------+----+
| | 4,548 | 4,276| 7,975| 0.27 | 1.75 |1.87| 5,231 | 0.13 |0.13|
|-----+----------+------+------+------+-------+----+--------+-------+----+
|_Ki._| 614 | 527| 1,604| 0.23 | 2.61 |3.04| 1,230 | 0.22 |0.26|
| | 357 | 259| 1,234| 0.30 | 3.45 |4.76| 1,036 | 0.32 |0.44|
| | 530 | 404| 1,084| 0.29 | 2.04 |2.68| 550 | 0.11 |0.15|
| | 925 | 890| 1,901| 0.28 | 2.05 |2.13| 905 | 0.10 |0.11|
| | 3,254 | 2,908| 4,570| 0.31 | 1.40 |1.57| 2,470 | 0.08 |0.09|
| |----------+------+------+------+-------+----+--------+-------+----+
| | 5,680 | 4,988|10,393| 0.29 | 1.83 |2.08| 6,191 | 0.12 |0.14|
|-----+----------+------+------+------+-------+----+--------+-------+----+
|_Ko._| 250 | 188| 471| 0.29 | 1.88 |2.50| 376 | 0.17 |0.22|
| | 496 | 347| 883| 0.29 | 1.78 |2.54| 357 | 0.08 |0.11|
| | 626 | 606| 1,003| 0.27 | 1.60 |1.65| 609 | 0.11 |0.11|
| | 718 | 709| 2,161| 0.26 | 3.00 |3.04| 918 | 0.14 |0.14|
| | 605 | 535| 2,397| 0.50 | 3.96 |4.48| 762 | 0.14 |0.16|
| |----------+------+------+------+-------+----+--------+-------+----+
| | 2,695 | 2,385| 6,915| 0.32 | 2.57 |2.90| 3,022 | 0.12 |0.14|
| |---------+-------+------+------+-------+----+--------+-------+----+
| |12,923 |11,649|25,283| 0.29 | 1.96 |2.17|14,444 | 0.12 |0.14|
+=====+==========+======+======+======+=======+====+========+=======+====+
The work done during the 5 months when these analyzed cost figures were
kept includes 280 ft. of bench and 220 ft. of heading. This excess of
bench over heading causes the general average amounts per cubic yard to
be too low.
[E] Actual amount of excavation.
[F] Amount of excavation paid for.
[Illustration: 24' 6" SPAN TWIN TUNNELS DETAILS OF METHOD OF DRILLING
AND BLASTING IN A TYPICAL (NOT EXACT AVERAGE) SECTION]
+---------+--------+--------+-----+-----+------+------+-------+
| Drilling and Firing Data for |
| Each Sub-division of Section |
|---------+--------+--------+-----+-----+------+------+-------|
| Sub | Volume | No. of | No. | No. |Total |Linear| Total |
|divisions|of each |sets of | of | of | lbs. | feet |length |
| | sub- | holes |holes|times| of | of |drilled|
| |division| | in |fired|powder|tunnel| |
| |paid for| | set | | per |broken| |
| | | | | | hole | | |
| | | | | |fired | | |
|---------+--------+--------+-----+-----+------+------+-------|
| _a_ | _b_ | _c_ | _d_ | _e_ | _f_ | _g_ | _h_ |
|---------+--------+--------+-----+-----+------+------+-------|
| _A_ | 17.775 | {[G] 1 | 6 | 3 | 4.50 | | |
| | | {[H] 1 | 9 | 1 | 1.50 | | |
| | | {[I] 1 | 6 | 1 | 1.00 | | |
| | | {[J] 1 | 6 | 1 | 0.75 | 6.0 | 195 |
| | | | | | | | |
|---------+--------+--------+-----+-----+------+------+-------|
| _A'_ | 1.00 | 2 | 3-4 | 1 | 0.25 | 5.0 | 21 |
|---------+--------+--------+-----+-----+------+------+-------|
| _B_ | 5.925 | {[G] 2 | 3-4 | 1 | 1.00 | 4.0 | 35 |
|---------+--------+--------+-----+-----+------+------+-------|
| _C_ | | {[K] 1 | 3 | 2 | 1.125| | |
| | 33.33 | 4 | 7 | 1 | 1.125| 5.0 | 186 |
|---------+--------+--------+-----+-----+------+------+-------|
| _D_ | 6.665 | 2 | 5-6 | 1 | 0.75 | 3.0 | 33 |
|---------+--------+--------+-----+-----+------+------+-------|
| | | |
| | | |
|=========+========+========+=====+=====+======+======+=======|
| _E_ | 50.00 | | 5 | 1 | 1.50 | 5.0 | 405 |
|---------+--------+--------+-----+-----+------+------+-------|
| _F_ | 88.88 |{ 10.5| 4 | 2 | 1.50 | | |
| | |{[L] 5.0| 4 | 1 | 1.50 | 4.0 | 682 |
|---------+--------+--------+-----+-----+------+------+-------|
| _G_ | 22.22 | 5.5| 4 | 2 | 1.00 | 5.0 | 132 |
|---------+--------+--------+-----+-----+------+------+-------|
| | | |
| | | |
|=========+========+========+=====+=====+======+======+=======|
| _H_ | 9.77 |{ 5 | 3 | 1 | 0.50 | | |
| | |{ 4 | 6 | 1 | 0.50 | 6.0 | 156 |
|---------+--------+--------+-----+-----+------+------+-------|
| _I_ | 26.66 | 8 | 5 | 1 | 1.00 | 6.0 | 252 |
|---------+--------+--------+-----+-----+------+------+-------|
| | | |
| | | |
| | |========+=====+=====+======+======+=======|
| | | |
| | | |
| | | |
| | |========+=====+=====+======+======+=======|
| | | |
+---------+--------+--------+-----+-----+------+------+-------+
+---------+------+-------+------+------+---------+-------+------+
| Drilling and Firing Data for |
| Total Sections |
|---------+------+-------+------+------+---------+-------+------|
| Sub |Total |Length | Cu. | Cu. | Total | Total | Total|
|divisions|length|drilled| yds. | yds. | lbs. of |lbs. of| lbs. |
| | of | per | per | per | powder | powder| of |
| |simi- |linear |linear|linear| per | per |powder|
| |lar |foot of| foot | foot | linear | foot | per |
| |head- |tunnel | of | of | foot of |drilled|cubic |
| |ings | |tunnel|tunnel| tunnel | | yard |
|---------+------+-------+------+------+---------+-------+------|
| _a_ | _i_ | _j_ | _k_ | _l_ | _m_ | _n_ | _o_ |
|---------+------+-------+------+------+---------+-------+------|
| _A_ | |Sigma | | | | | |
| | | c + d |b + i | j |c + d + f| m | m |
| | | ----- |------| --- | ----- | --- | --- |
| | | g | g | k | g | j | k |
| | 2 | 65.00 | 5.925|10.97 | 17.00 | 0.261 |2.848 |
|---------+------+-------+------+------+---------+-------+------|
| _A'_ | 2 | 8.40 | 0.400|21.00 | 0.70 | 0.166 |1.750 |
|---------+------+-------+------+------+---------+-------+------|
| _B_ | 2 | 17.50 | 2.962| 5.90 | 3.50 | 0.200 |1.181 |
|---------+------+-------+------+------+---------+-------+------|
| _C_ | | | | | | | |
| | 1 | 37.20 | 6.666| 5.58 | 6.975 | 0.187 |1.046 |
|---------+------+-------+------+------+---------+-------+------|
| _D_ | 2 | 22.00 | 4.444| 4.95 | 5.500 | 0.250 |1.237 |
|---------+------+-------+------+------+---------+-------+------|
|Total for| |150.10 |20.397| 7.81 | 33.675 | 0.227 |1.778 |
| Heading | | | | | | | |
|=========+======+=======+======+======+=========+=======+======|
| _E_ | 1 | 81.00 |10.000| 8.10 | 13.500 | 0.167 |1.350 |
|---------+------+-------+------+------+---------+-------+------|
| _F_ | | | | | | | |
| | 1 |170.50 |22.222| 7.67 | 23.230 | 0.136 |1.046 |
|---------+------+-------+------+------+---------+-------+------|
| _G_ | 1 | 26.40 | 4.444| 5.94 | 4.400 | 0.166 |0.990 |
|---------+------+-------+------+------+---------+-------+------|
|Total for| |277.90 |36.666| 7.56 | 41.150 | 0.150 |1.133 |
| Bench | | | | | | | |
|=========+======+=======+======+======+=========+=======+======|
| _H_ | | | | | | | |
| | 1 | 26.00 | 1.628|15.96 | 3.250 | 0.125 |1.995 |
|---------+------+-------+------+------+---------+-------+------|
| _I_ | 2 | 84.00 | 4.444|18.90 | 13.333 | 0.158 |3.000 |
|---------+------+-------+------+------+---------+-------+------|
|Total of | |110.00 | 6.072|18.10 | 16.583 | 0.151 |2.731 |
| Trench | | | | | | | |
|=========+======+=======+======+======+=========+=======+======|
|Total for| |548.00 |63.135| 8.95 | 91.408 | 0.172 |1.446 |
| Whole | | | | | | | |
|Section | | | | | | | |
|=========+======+=======+======+======+=========+=======+======|
|Powder taken at 0.5 lb. per stick |
+---------+------+-------+------+------+---------+-------+------+
[G] 6 Cut Holes-8 feet (Black circle)
[H] 9 First Side Rd. and Bottom-7 feet (Circle with dot in it)
[I] 6 Back Round-7 feet (Circle with line in it)
[J] 6 Top Back Round-7 feet (Circle with x in it)
[K] A' 7 Holes-3 feet (Open circle)
[L] line holes (Plus sign)
TABLE 7.--Analysis of Drilling Time on Section Gy-East.
+========+======+========+=====+=====+=======+========+========+=======+
| | | | AVERAGE TIME TAKEN: |
|Position|Nature| No. of |-----+-----+-------+--------+--------+-------|
| in | of | Drill | | | | | | |
|Section.|Rock. | Shifts |Set- |Dril-|Neces- |Unneces-| Taking |Loading|
| | |observed|ting |ling.| sary | sary | down | and |
| | | for | up. | |delays.|delays. |machine.|firing.|
| | |average.| | | | | | |
|--------+------+--------+-----+-----+-------+--------+--------+-------|
| | | |h. m.|h. m.| h. m. | h. m. | h. m. | h. m. |
| | | |-----+-----+-------+--------+--------+-------|
|Heading |Quartz| 8 |0:38 |4:52 | 1:40 | | 0:05 | 0:04 |
| | | | | | | | | |
|Heading | Hard | 1 |0:15 |8:00 | 1:45 | | | |
| | mica | | | | | | | |
| |schist| | | | | | | |
| | | | | | | | | |
| Bench |Quartz| 23 |1:23 |5:57 | 2:23 | 0:05 | 0:05 | 0:07 |
| | | | | | | | | |
| Bench |Medium| 16 |1:10 |6:08 | 1:50 | 0:12 | 0:07 | 0:07 |
| | mica | | | | | | | |
| |schist| | | | | | | |
| | | | | | | | | |
| Center |Medium| 10 |0:58 |5:53 | 1:33 | 0:06 | 0:12 | 0:30 |
| trench | mica | | | | | | | |
| |schist| | | | | | | |
| | | | | | | | | |
| Center | Soft | 9 |1:10 |6:40 | 1:17 | 0:10 | 0:20 | 0:23 |
| trench | mica | | | | | | | |
| |schist| | | | | | | |
|--------+------+--------+-----+-----+-------+--------+--------+-------|
|General | | 67 |1:08 |5:58 | 1:53 | 0:07 | 0:09 | 0:12 |
|average | | | | | | | | |
|--------+------+--------+-----+-----+-------+--------+--------+-------|
| Per- | | |11.3%|59.7%| 18.9% | 1.1% | 1.5% | 2% |
|centage | | | | | | | | |
+========+======+========+=====+=====+=======+========+========+=======+
+========+======+=========+========+======+======+========+
| | | AVERAGE TIME TAKEN: | FEET DRILLED. |
|Position|Nature|---------+--------+------+------+--------|
| in | of | | | | | |
|Section.|Rock. | Total |Mucking.|Total.| Per | Per |
| | |drilling.| | |shift.|working |
| | | | | | | hour. |
| | | | | | | |
|--------+------+---------+--------+------+------+--------|
| | | h. m. | h. m. |h. m. | | |
| | |---------+--------+------+------+--------|
|Heading |Quartz| 7:19 | 2:41 |10:00 | 22.0 | 2.86 |
| | | | | | | |
|Heading | Hard | 10:00 | |10:00 | 42.0 | 4.20 |
| | mica | | | | | |
| |schist| | | | | |
| | | | | | | |
| Bench |Quartz| 10:00 | |10:00 | 25.9 | 2.59 |
| | | | | | | |
| Bench |Medium| 9:34 | 0:26 |10:00 | 22.22| 2.32 |
| | mica | | | | | |
| |schist| | | | | |
| | | | | | | |
| Center |Medium| 9:12 | 0:48 |10:00 | 22.0 | 2.39 |
| trench | mica | | | | | |
| |schist| | | | | |
| | | | | | | |
| Center | Soft | 10:00 | |10:00 | 26.44| 2.64 |
| trench | mica | | | | | |
| |schist| | | | | |
|--------+------+---------+--------+------+------+--------|
|General | | 9:27 | 0:33 |10:00 | 24.1 | 2.54 |
|average | | | | | | |
|--------+------+---------+--------+------+------+--------|
| Per- | | 94.5% | 5.5% | 100% | | |
|centage | | | | | | |
+========+======+=========+========+======+======+========+