At the Morteros, hike further.
As you see a small rock canyon on the left, hike uphill on the left side of the wash.
Stay away from the boulders and hike diagonally left up the hill.
The terrain is sandy with some boulders.
Over the ridge are a couple of old mines.
"Mine 1" looks open, "Mine 2" is blocked by a boulder.
It will be difficult to find the mines this way without a GPS.
At "Mine 2" there is a faint road visible, marked by rock cairns.
Look for the road below, where it meets 2 washes, that's where you want to end up.
Follow the road below, that's clear at first, but gets fainter and fainter.
At the dirt road below, turn left and hike on the road or take the wash.
Further on the California Riding and Hiking trail turns left, hike it back to the car.
Alternative without a GPS:
At the parking hike downhill, in the wash left of the road.
This is the California Riding and Hiking Trail.
As the trail crosses the asphalt follow it.
The trail is faint, but marked by orange markers.
At the dirt road, turn right and follow it.
At the Y crossing Oriflamme - Rodriguez canyon, take the right fork, named Rodriguez canyon.
Once past the fork, you should be able to see the old mine road running along the hill to the right.
About 400 yard, beyond the crossing, you find a faint road to the right.
There are no markers, but there may be some rock cairns.
If you can't find the start, just hike toward the road, that is visible along the hill on the right (north).
Follow the road uphill, the road is sometimes very very faint and hard to find, look for rock cairns.
Just before the end of the road, that is clearly visible at this point, look for the rubble that came out of the mine. The mine itself is not visible, but the debris is.
Try to find the road, that is even less obvious at this point.
Shorter alternative.
Drive the dirt road to the Oriflamme canyon, that is clearly marked.
The road follows the wash north/west at the fork, read the text above.
The dirt road follows the wash, so it's sandy, an AWD may be needed. So don't blame me if you get stuck in the sand with a regular car.