I visited this WHS in August 2020. Due to the works being carried out till 2021 to upgrade the Krzemionki tourist route underground experience and make it more accessible, I couldn't 'enjoy' the full experience, but based on photos, videos and other reviews, the only value added I missed when compared to the Spiennes WHS, was the pictogram/rock art, used as the museum's logo.

Thanks to Martina and Ivan's previous visit and help, and to avoid a forecast thunderstorm in the Zamosc area, I decided to go ahead and try to have a look at what's on offer at all 4 locations. The GPS coordinates on the official UNESCO website are precise although you'll have to zoom in and out of your GPS to make sure you avoid unpaved roads, pathways or non-existant roads. I started with the Krzemionki Museum and Archaeological Reserve which is a well-developed gateway to just one of the 4000 prehistoric mines of striped flint near Ostrowiec Swiezokrzyski. The WHS is unique mostly due to the well-preserved mining waste piles and shaft depressions, which despite thousands of years remained almost unchanged, even though most is covered by fast growing overgrowth, so much so that near the museum is a nature reserve with boardwalks.

In Krzemionki, all the techniques of obtaining flint can be observed, from the simplest cavities to large sophisticated mines, i.e. sophisticated  for Neolithic and Early Bronze Age times. This complex of mines was only discovered in 1922 by a geologist and contains some 4000 mines, the largest of which have a depth of nine metres. Of all these mines, only the 500 metres underground tourist route is accessible.

After a long drive, I reached the huge parking lot, and headed towards the public toilets area, where on the wall I saw the unique striped flint for the first time. The nature reserve seems quite small but in actual fact is some 378 hectares and a local guide is recommended to avoid getting lost if you venture away from the boardwalks. Opposite the museum, to the left of the parking lot, I walked down a one-way road. The gate was open when I visited and so I could enter to explore the area above ground which is usually covered with a guide as part of the tourist route. There's a reconstruction of a Neolithic settlement (how researchers imagine the Gawroniec Settlement looked like), a miners camp flint workshop and a sheltered shaft. Judging by the current state of this area, the lack of construction vehicles or any sign of restoration works above ground, it seems that there's no rush to start, continue or finish the upgrading works and re-open this museum before the COVID-19 crisis is over. 

The term mining fields used by UNESCO to describe Krzemionki, Borownia and Korycizna is very appropriate as what you'll see at the moment is an overgrown field with mining remnant hills which in reality are waste piles or slag heaps. The UNESCO site map coordinates are precise and a metal sign has supposedly been placed at each location with a white and blue "Zabytek" (monument) logo and some information. I wrote supposedly because overgrowth seems to have literally swallowed everything, including the metal signs. Out of the 4 locations I visited, I only just managed to find the one in Borownia, which in a couple of months at most will be also covered by overgrowth. For the time being, there isn't any UNESCO sign, not even on the brown signs on the main roads.

I'm still glad I explored the area, and since Krzemionki is only around 2.5hrs-3hrs away from Warsaw or the border with Slovakia, I wouldn't mind revisiting when the the tourist route reopens. Until then, I'm very happy with the polished striped flint souvenir I bought as I always thought that all types of flint were black. Overall, especially since I only explored the area above ground, I think its inscription is justified and I agree with previous reviewers that it is not a duplicate of Spiennes but is a much more 'complete' prehistoric mining WHS.