You will find only a handful of expats in either of those towns. Yes, I would consider them safe places if you follow usual practices.
You should be able to find a decent rental in either place. La Pintada is a bit cooler, touristy and upscale than Penonome. Understand that both areas are unsophisticated; internet advertising will be limited. You may have to go there to actually find a rental.
Not knowing you, the biggest problem with living there might be the presence of very little English and also cultural boredom.
Is the mine near Santa Fe which is north of Santiago? I know a retired Canadian couple who live in San Carlos north of the Pan Am hwy, names Mannell, forgot where in Canada they are from but an interesting story, I helped a Canadian couple who lived in Pedasi & were returning to live in Vancouver find a home for their dogs by advertising on another PTY blog & it turned out the dogs new home was with the Mannell's, the dog didn't even have to learn a new language Ja ja. LoL Lots of Canadians in the city, I attended a Canadian Thanksgiving party at the Union Club where the ambassador attended. Also if you get to Playa Farallon see if Woody's is still open on the beach west of Decameron, Woody has passed away but last I heard his wife was still running "Woody's", Woody was a CanForce C-130 Flight Engineer, R.I.P PL
I am a bit surprised the mine doesn't provide relocation assistance.
Nevertheless, if you are looking for rentals your two new best friends are Encuentra24 and OLX
Houses for rent in Penonome can be found here. https://www.encuentra24.com/panama-en/real-estate-for-rent-houses#regionslug=prov-cocle-penonome&page=1
and here https://penonome.olx.com.pa/apartamentos-casas-alquiler-cat-363
There are no rentals listed online for La Pintada, but as is usual with Panama the bulk of the rentals are not online, you need to be on the ground and beat the bushes to find them.
My preference would be La Pintada, mainly for the cooler climate and more peaceful surroundings as it is up higher in the mountains. But it is a tiny little place where the dogs and chickens out number the people that live there and there will be no real services to speak off other than a few little mini supers and a restaurant. You will ultimately have to go to Penonome for shopping on a regular basis.
Penonome is down in the flats and hot and noisy and always traffic jams, but it is the provincial capital and that is where you will find all the services.
There are some but not a lot of expats in either area, most are farther along the coast in San Carlos, Coronado area, too far for you to reasonably commute.