The above is the mule-train.
Now let's focus on the borax works.
This is what the "factory" looked like during it's hey day. Below is what it looks like now.
The storage barn that was out front is gone, but this part is pretty much intact. (Look beyond the structure! Look at that valley! and the mountains and sky! I simply cannot get over how pretty "Death" Valley is!)
Anyway, back to borax...
As you can see, the gathering of the borax "cottonballs" was done by Coolies. The influx of "Chinamen" began because importing African slaves was becoming unacceptable and/or illegal. So in the late 1840's Europeans and Americans began hiring men from the Far East at rock-bottom wages. The term "Coolie" is from Hindi - kuli means "wages."
Most coolies came of their own free will through contractual agreements - much like the indentured servants of the 1700's - but never put it past mankind to shanghai a few. Free will or not, these men weren't treated much better than the African slaves that came before them other than the fact that they did receive wages. The Chinese government had a ban on emigration (immigration means coming into a country; emigration means going out of a country), but it was just on paper. They didn't seem to care if people were leaving their country. Suffice it to say, therefore, that the Chinese government didn't do much to improve the treatment of emigrants.
The wages were $1.30 a day - not bad for the 1800's! - but then the owners deducted housing and company store expenses.
By the late 1800's free immigration was replacing the coolie trade. People who came from China, Japan, and Hindustan would continue to be known as coolies, but they were no longer bound by contracts. Technically they were free immigrants.
So, the coolies would gather the borax. Because transportation costs (meaning not just money, but the wear and tear on men and animals and equipment, too.) Transportation cost was so high that they processed the "cottonballs" on site and only transported pure borax. Not so pretty, eh.
They would boil the raw material in water. Adding carbonated soda caused the borax to separate from the lime and mud which settled to the bottom of the tank. They drew off the borax into cooling tanks. It would crystallize onto hanging metal rods. The coolies chipped it off the rods and reprocessed it to get the most concentrated form of borax possible. The coolies then bagged the borax and stored it in the barn until shipment out of the valley.
The good news is that borax will not crystallize in temperatures above 120 F, so processing ceased during the hottest part of the year. I suspect, though, that that's when the owners would have the coolies do maintenance on the facility.
Then the concentrated borax would be loaded into the wagons - as much as 36 tons (72,000 pounds!) - including 12,000 gallons of drinking water. The rear wheels on those wagons were seven feet high! That's taller than Granpa!! But those large wheels were better able to manage uneven surfaces. There was no modern road grading equipment for sure.
This map also shows the location of the four borax companies operating in Death Valley in the late 1800's.