Work in the bottini proceeded quite slowly because only one person at a time could in the tunnel. The workers dug using rudimentary equipment, such as shovels, tufa picks (which had only one point), or rock picks (with two points), spades, various types of drills, stone masons' mallets, chisels, and other implements for chipping away the calcite deposits from the water channel. Another device used was the archipendolo, a surveying instrument shaped like an "A" from which hangs a plumb line, used to establish the gradient, often an imperceptible incline of as little as 1:1000, thus the water, as it slowly flowed, could deposit any impurities. If the initial gradient was too steep they would build a set of serpentine switch backs which would slow the course of the water and decrease the incline so as to maintain a constant gradient. To illuminate the darkness the city furnished tallow candles and sometimes lanterns.

After a tunnel had been roughly hewn, the workers arranged to enlarge it and at the same time to reinforce it with arches, transepts, and often brick piers to avoid cave-ins and settling. Thus, behind the miners work carpenters and many other persons, like the haulers, the caterers (because the city realized that it would save time if it provided meals underground instead of having the workers go outside for their lunch break). These workers had different terms of employment: the laborers were hired by the day and were paid right away (often weekly), but their jobs were not at all secure. The master craftsmen, experts in their fields, had long-term contracts and were paid double the laborers' wages, who in turn, earned twice as much as the female laborers. The pay always included a meal: bread, wine, melon, and sometimes meat.

There were also specialists recruited from among the miners of the Colline Metallifere the metal-bearing hills near Siena (Massa Marittima, Gerfalco, Montieri, Boccheggiano), who had secure, long-term contracts. These miners were called "Guerchi", a word with a German derivation meaning "blind" (the most popular explanation being that they were called so because after working for months underground, when they first re-emerged into the sunlight, they were blinded by the brightness. Life underground, besides being dangerous and unhealthy, also fostered widespread fears, caused above all by the darkness and ignorance: workers reported seeing mythological animals, like the Fuggisole, or Shadowlurker, capable of injecting its prey with venom, or evil demons who could poison the workers with their breath (the explanation of which could lie in the frequently occurring pockets of natural gas). They also imagined the presence of dwarves, called "homicciuoli", who resembled little old men; instead of bothering the workers they gladdened them (the workers drank a lot of wine, lavished upon them in the belief that it gave them strength, and in order to put fear and nightmares out of their minds, so it could have been the alcohol itself that caused the symptoms).

In sum, despite the often inhumane conditions of the workers and the dangers of cave-ins and accidents, the records show very few injuries, and even fewer deaths occurred on the job, even though thousands of persons worked in the bottini over a period of many centuries.