De la Pirotechnia

...dedicate it (as is customary) to the Most Holy Trinity, or to our Lady, or to the name of some other Saint for whom you have devotion, invoking their protection; and thus you will spiritedly begin to dig, with the intent of continuing and not ceasing until your means can no longer support the expense, or until you have surpassed the limits marked by the signs mentioned above.

A woodcut illustration depicts a mining and processing site under a timber-framed shed with a tiled roof. On the left, a man stands beside a large wooden vat, using a heavy pestle or mallet to crush materials. In the center, a man works at a raised hearth or furnace where a fire is burning. To the right, a third man pushes a small, rectangular cart or trolley, likely laden with ore, toward the dark entrance of a mine or kiln. The surrounding landscape shows hilly terrain under a clear sky.

Always taking care to begin the opening of the excavation at the bottom, and as near as you can to the base and root of the mountain, in such a way that the excavation, traveling in a straight line, crosses the vein original: "filone" of the mine by the shortest and safest path shown to you. This path (although often well-begun by the diggers) is not well-followed, either because they do not know how to maintain the excavation (about which one must take great care), or because they are drawn by the hope of certain mineral branches original: "rametti minerali"—these are small offshoots of ore that can lead a miner away from the primary, more profitable vein. that are sometimes found while digging, and they often deviate from the straight path. However (although such branches should be followed), one must not leave the order of the designed path, but continue forward. And beyond these other precepts, keep it in your memory to ensure that while digging, you avoid as much as you can cutting through shattered and soft stones, for they are dangerous due to the risk of collapse, and it is rare that minerals are found within them.

BUT FINDING THEM and it appearing to you that they cannot be avoided, I encourage you—where such fear shows itself—to use every possible diligence to well-fortify the excavation for the safety of your investment and to save the lives of the workers. Do this with masonry arches original: "archi di muro" and cross-timbers in the manner of reinforced beams, or with thick and powerful vertical props original: "pentelli" made of good and strong oak wood or other trees. And this is the way in which one must proceed in the digging of mines, so that you may safely enjoy the fruit of your labors. AND BECAUSE (as is seen by the old excavations they left behind) the ancients used another method in this work: instead of beginning from the bottom at the roots of the mountains (as the moderns do), they began the excavation in the upper part, where the vein appeared to them on the surface by daylight. And...