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A shaft may be described as a vertical or inclined tunnel from surface for conveyance of men, materials, ventilation, pumping water, in addition to hoisting ore and waste rock. During the life of the Cost Book there were six shafts being sunk from time to time at Wheal Agar. The two important ones were New Engine and Windstraw Shafts. The others were Boundary and Dobree's shafts, and three unnamed exploration or ventilation shafts. New Engine Shaft At the time of the commencement of the Cost Book in October 1855 the shaft bottom was just below the 24 fathom level. A pare of James Pope & Co. consisting of 9 men, were sinking at a rate of 4.5 metres per month at a price of £18 per fathom. We do not know the dimensions of this shaft but it was probably no larger than 2.4 metres by 2.0 metres. The number of men in the pare would perhaps indicate that they worked on 3 shifts with intervals for fume clearance after blasting. By the end of December 1855 James Pope & Co. had reached the 36 fathom level and their price had been increased to £22 per fathom. They met some water problems in November and were awarded with an additional £0.58 for baling the water up to the adit level. At this point it should be noted that the Company had bought a second hand Cornish Engine from Penhale Mine, and during October James Nicholls and another man had started dismantling it at a cost of £6.50. This engine had been selected for the New Engine Shaft. The details and costs of dismantling, carriage to Wheal Agar and installation are all recorded in the Cost Book. This will be summarised under the section named 'Building Engine Houses'. 36 fathom to 48 fathom Meanwhile in January 1856 James Pope & Co were cutting a plat of 7 metres at the 36 fathom level for which they were paid £34.50 for the month with an additional £6 for planking and dividing the shaft. Sinking did not start again until March because the pare were engaged in 'cutting ground at the adit level and taking up water', and earned another £3. This work was probably to make room for a whim for drawing water from the shaft bottom during sinking and which they erected in February. In the same month the pare also advanced a drive for 5 and 3 metres north and south respectively, but perhaps more correctly they were cross-cuts to intersect the north and south lodes. Sinking the shaft started again in March 1856 but not before they had erected a penthouse and hanging tackle. Penthouse is the Cornish name for pentice which is a timber protection installed across the shaft for the safety of the shaft sinkers underneath. The penthouse would have had a trap door through which the shaft sinkers and kibbles could pass. Three more men were added to the pare in March and in July the 48 fathom level had been reached with a record sinking speed in May of 5.95 metres, the contract price during the last three months being £26 per fathom. 48 fathom to 60 fathom In August 1856 the same routine was carried out as in February with cutting a plat, removing the old penthouse and putting in a new one under the 48 fathom level, and also driving a short distance north from the plat. However a different pare under the name of William Wearne & Co took over the work and in September they obtained a much higher price of £44 per fathom. Sinking continued for the next few months until February 1857 when they holed through to a crosscut on the 60 fathom level driven from an older shaft. For this they received a bonus of £1.80 and it increased their take home pay for the month to £46.98 between the twelve men. 60 fathom to 70 fathom Having reached the 60 fathom level they needed to sink a little further to make room for a penthouse underneath. The 60 fathom plat was not completed until May 1857 and this permitted drives to be started in both east and west directions along the north lode. While the shaft was being sunk it was also being widened from surface down to the 36 fathom level to make room for a 'skip road'. The traditional method of hoisting rock was by horse whim and kibbles. With the purchase of the new Cornish engine the decision had been made to use the engine both for pumping water and also hoisting skips, the latter replacing the kibbles. A skip is a container for hoisting rock, usually running on rails. (Please refer to the Glossary page for clarification of mining terms). In May 1857 William Wearne and his pare of twelve men continued sinking the shaft down to the 70 fathom level which they reached in January 1858. With the increased depth the value of the contract varied between £40 and £46 per fathom. Before the pare could continue the sinking many jobs had to be done, such as cutting bearer holes for a cistern in the shaft at the 70 fathom level, cutting a plat, putting in a new penthouse and removing the old one above. They also did some stoping which would indicate that the shaft had either intersected the ore, or was following it. 70 fathom to 81 fathom The sinking commenced again in April of 1858 with William Wearne & Co and an additional six boys for 'drawing water'. By December of the same year the pare had sunk another 11 metres after which sinking was then halted, and did not resume during the life of the Cost Book. Summary of Sinking in New Engine Shaft 1st October 1856 to
31st December 1858. (39 months)
Windstraw Shaft This shaft was first mentioned in the Cost Book in February 1856, in an entry concerning a winze being sunk under the 33 fathom level on Wheal Fortune Lode east of Windstraw Shaft. The spelling of this name in some other records has been shown as Windstow, but I will keep the spelling as given in the Cost Book. This shaft was at the Eastern end of the Wheal Agar sett and the photograph below shows what I think is the location of the burrow to the east of Chariot Road:-
Carn Brea is in the background with the monument to Lord Francis Basset clearly seen in the centre. In March 1856 a pare with the name of Richard Luke & Co. (6 men), began sinking the shaft under the 33 fathom level. The price per fathom was set at £6 per fathom which was considerably less than New Engine Shaft, and probably it was a smaller cross section. In April the price was set at £9 and it increased again in May to £13 per fathom. It would appear also that the shaft may have been sunk in the lode as an entry in the Cost Book says 'copper ore bought of them' (sic) and for which they were paid £1.15. In June 1856 a different pare of 6 men under the name of John Goldsworthy & Co. took over the sinking, and were followed in July by another pare of 6 men under the name of Jos/h Gribble & Co. Whether Jos/h stands for Josiah, Joseph or Joshua I do not know as it is always abbreviated as shown. This pare completed the sinking to the 40 fathom level, after which they did some widening of the shaft, cut a plat and commenced driving west with 4 men until July 1857. They reached a point 63 metres west of the shaft and one wonders what the air must have been like at this dead end with smoke from tallow candles and gunpowder fumes. There is no confirmation that connections were made to any winzes from the level above or older workings, nor any mention of air sollars being installed. 40 fathom to 50 fathom During the previous five months of work to reach the 40 fathom level the average monthly sinking rate was 4 metres. While the east and west drives were being driven from the 40 fathom level the sinking operation was suspended until May 1857 when a pare of 4 men in the name of Josiah Angove & Co. put in a penthouse and made a start on the next sinking cycle. He added two more men to his pare and they reached the 50 fathom level in October 1857 averaging 4 metres per month. Here the sinking was again suspended for seven months while drives were driven east and west to a distance of 36 metres, and at the same time winzes were being sunk from the 40 fathom level above. In April and May 1858 some stoping was carried out in the bottom of the shaft at a rate of 15 shillings per fathom, and presumably this should have read 'per square fathom'. When this was completed the entry in the Cost Book for June reads 'Clearing shaft, taking up water, putting in Penthouse, hanging tackle etc' (sic). 50 fathom to 56 fathom In June 1858 Josiah Angove & Co. and his pare of 6 men began sinking again at a rate of £15 per fathom and this was increased to £16 in July. Then in August another 6 men joined the pare with the rate increased to £17 per fathom and by the end of the month they had sunk 10.5 metres since June. 50 fathom to 56 fathom In June 1858 Josiah Angove & Co. and his pare of 6 men began sinking again at a rate of £15 per fathom and this was increased to £16 in July. Then in August another 6 men joined the pare with the rate increased to £17 per fathom and by the end of the month they had sunk 10.5 metres since June. At this point sinking was stopped and a decision was made to install an engine for both pumping and winding. This necessitated widening of the shaft to make room for a skip road, and in November work started from surface described as 'Cutting down and securing Windstraw Shaft'. By the end of April 1859 the engine had been installed and commenced working, with a new name given to the shaft as Eastern Engine Shaft. 56 fathom to 60 fathom In May sinking started again with a pare of 9 men under the name of William Hosking & Co. and during the month they sank 4.65 metres at a rate of £20 per fathom. They obviously came across some good ore and spent the month of June in stoping at a rate of £1.30 per square fathom, as well as putting in more of the skip road. Sinking began again in July by the same pare and reached the 60 fathom level after 3.05 metres. During August the pare began driving east and west, as well as 'putting in sollar and footway for bargain', and also 'watching engine'. the pare being assisted by 3 boys. 60 fathom and under In September 1859 the same pare sank another 4.27 metres as well as 'casing down shaft', 'hanging tackle' and 'watching engine'. Lastly in October and November with 9 men and 3 boys they made 8.53 metres and continued 'casing down shaft' as well as putting in a penthouse under the 60 fathom level. What happened after this we will need to find in the new cost book if it is still in existance. Summary of sinking in Windstraw (Eastern Engine Shaft) March 1856 to November 1859 (45 months)
Sinking other shafts Boundary Shaft. This shaft was located at the east of the sett on the boundary with Wheal Tehidy. It had reached the 40 fathom level by the start of the Cost Book in October 1855, and was sunk intermittently from then on. Summary of sinking in Boundary Shaft
Other Shafts Dobree's Shaft. A small amount of sinking was carried out in July, September and October 1857 to take the shaft below the 40 fathom level. The average advance per month was 4.31 metres at a cost of £3.78 per metre. Miscellaneous Shafts There were two exploration or ventilation shafts sunk under adit level, the first entries being in November and December 1857, and the second in May and June 1858. A total of 16.31 metres were sunk with an average advance of 4.08 metres per month, and at a low cost of £1.08 per metre. There was another exploration or ventilation shaft sunk from surface for 8.23 metres during February 1858, after which the same pare of two men drove north for 13.72 metres in the same month. It must have been relatively soft ground, the rate per fathom for the shaft being £0.63 and for the drive £1.00.
Observations It is difficult to make comparisons between the costs per metre for shaft sinking without knowing the cross sectional area of the shaft, rock conditions, ground water, depth of shaft, type of hoisting and other factors. However it would seem that with hand boring an average rate of 3 to 4 metres per month would be an acceptable estimate for the larger shafts to a depth of 70 fathoms, with an extra two months of time at each level for excavation of the plat and installation of a penthouse, hanging tackle and ladder way. |
