This page explains how to find the Kayra Mah shrine and solve the "Greedy Hill" puzzle.
How to Find the Shrine
Talk to Bladon in Goron City to start the shrine quest "A Brother's Roast". Look for Gorko Lake on the map, and look west of it to see a slope leading up to that area from the main road. Exit Goron City via the west exit, and take the road south until you reach that slope. Go toward Gorko Lake until you see a sign pointing to Gorko Tunnel. Go there and talk to Gonguron.
After the cutscene, leave Gorko Tunnel and go southwest down the slope, toward Gortram Cliff. You will encounter Moblins and Fire Chuchus, as well as falling boulders, so proceed with caution.
At the bottom of the slope, just beyond the pool of lava, there is a ledge with Rock Roasts on it. Pick one up and start to carry it up the slope. You will find that more Moblins have appeared. Make your way back up the slope, setting down the Rock Roast as needed to fight enemies. Watch out for falling boulders. As you get close to the top of the slope, a huge boulder will fall, so go off to the side to avoid it.
Then go back into Gorko Tunnel and approach Bladon. A cutscene will occur, and the shrine will be revealed.
How to Solve the Shrine
Go up the stairs and up the slope. As you go up, large metal spheres and small spiked spheres will roll downward. Dodge through the gaps in the thin walls separating the three lanes. Sometimes, rupees will fall as well, but they are usually followed by more spiked spheres. The rupees that fall down the middle can be retrieved later, but the ones on the sides will fall down into the bottomless pits near the shrine elevator.
On the right side of the slope as you go up, there is a treasure chest in a niche on the right. It contains a Ruby.
Near the top of the slope, several red rupees will fall. If you gather any, run to the next lane afterward, to avoid the spiked spheres that follow them.
At the top of the slope, jump and use the paraglider to reach the treasure chest on the ledge. It contains five Bomb Arrows.
After this, you can go back down to the bottom of the slope and use Magnesis to move the spheres out of the way to check for rupees that didn't fall into the bottomless pits.
Then go back up and talk to Kayra Mah to get the Shrine Orb.